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Pottel H, Nyman U, Björk J, Berg U, Bökenkamp A, Dubourg LD, Lemoine S, Goffin K, Grubb A, Hansson M, Larsson A, Littmann K, Åsling-Monemi K, Adeli K, Cavalier E, Delanaye P. Extending the cystatin C based EKFC-equation to children - validation results from Europe. Pediatr Nephrol 2024; 39:1177-1183. [PMID: 37875730 DOI: 10.1007/s00467-023-06192-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/27/2023] [Accepted: 09/29/2023] [Indexed: 10/26/2023]
Abstract
BACKGROUND A new cystatin C based European Kidney Function Consortium (EKFCCysC) equation was recently developed for adults, using the same mathematical form as the previously published full age spectrum creatinine based EKFC-equation (EKFCCrea). In the present study the cystatin C based EKFC-equation is extended to children, by defining the appropriate cystatin C rescaling factor QCysC. METHODS Rescaling factor QCysC for cystatin C was defined as: a) 0.83 mg/L, exactly as it was defined for young adults in the adult equation, and b) a more complex QCysC-age relationship based on 4th degree cystatin C-age polynomials after evaluation of data from Uppsala, Stockholm and Canada and aggregated data from Germany. The EKFCCysC equation was then validated in an independent dataset in European children (n = 2,293) with measured GFR, creatinine, cystatin C, age, height and sex available. RESULTS The EKFCCysC with the simple QCysC-value of 0.83 had a bias of -7.6 [95%CI -8.4;-6.5] mL/min/1.73 m2 and a P30-value of 85.8% [95%CI 84.4;87.3] equal to the EKFCCysC with the more complex 4th degree QCysC-value. The arithmetic mean of the EKFCCrea and EKFCCysC with the simple QCysC of 0.83 had a bias of -4.0 [95%CI -4.5;-3.1] mL/min/1.73 m2 and P30 of 90.4% [95%CI 89.2;91.6] similar to using the more complex 4th degree QCysC-polynomial. CONCLUSION Using exactly the same QCysC of 0.83 mg/L, the adult EKFCCysC can easily be extended to children, with some bias but acceptable P30-values. The arithmetic mean of EKFCCrea and EKFCCysC results in bias closer to zero and P30 slightly over 90%.
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Affiliation(s)
- Hans Pottel
- Department of Public Health and Primary Care, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium.
| | - Ulf Nyman
- Department of Translational Medicine, Division of Medical Radiology, Lund University, Malmö, Sweden
| | - Jonas Björk
- Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden
- Clinical Studies Sweden, Forum South, Skåne University Hospital, Lund, Sweden
| | - Ulla Berg
- Department of Clinical Science, Intervention and Technology, Division of Paediatrics, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Arend Bökenkamp
- Emma Children's Hospital, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Laurence Derain Dubourg
- Néphrologie, Dialyse, Hypertension et Exploration Fonctionnelle Rénale, Groupement Hospitalier Edouard Herriot, Hospices Civils de Lyon, Université Claude Bernard Lyon 1, and Laboratory of Tissue Biology and Therapeutic Engineering, UMR 5305 CNRS, Université Claude Bernard Lyon 1, Lyon, France
| | - Sandrine Lemoine
- Néphrologie, Dialyse, Hypertension et Exploration Fonctionnelle Rénale, Groupement Hospitalier Edouard Herriot, Hospices Civils de Lyon, Université Claude Bernard Lyon 1, and Laboratory of Tissue Biology and Therapeutic Engineering, UMR 5305 CNRS, Université Claude Bernard Lyon 1, Lyon, France
| | - Karolien Goffin
- Department of Nuclear Medicine, Division of Nuclear Medicine and Molecular Imaging, University Hospital Leuven, KU Leuven, Louvain, Belgium
| | - Anders Grubb
- Department of Clinical Chemistry, Skåne University Hospital, Lund University, Lund, Sweden
| | - Magnus Hansson
- Function Area Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital Huddinge and Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Anders Larsson
- Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden
| | - Karin Littmann
- Department of Medicine Huddinge, and Medical Unit of Endocrinology, Theme Inflammation and Ageing, Karolinska Institutet, Stockholm, Sweden, Karolinska University Hospital, Stockholm, Sweden
| | - Kajsa Åsling-Monemi
- Department of Clinical Science, Intervention and Technology, Division of Paediatrics, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Khosrow Adeli
- Clinical Biochemistry, Paediatric Laboratory Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Etienne Cavalier
- Department of Clinical Chemistry, University of Liège, CHU Sart Tilman, Liège, Belgium
| | - Pierre Delanaye
- Department of Nephrology-Dialysis-Transplantation, University of Liège (ULg CHU), CHU Sart Tilman, Liège, Belgium
- Department of Nephrology-Dialysis-Apheresis, Hopital Universitaire Caremeau, Nîmes, France
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2
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Ntaios G, Brederecke J, Ojeda FM, Zeller T, Blankenberg S, Schnabel RB. New race-free creatinine- and cystatin C-based equations for the estimation of glomerular filtration rate and association with cardiovascular mortality in the AtheroGene study. Intern Emerg Med 2024; 19:697-703. [PMID: 38351263 PMCID: PMC11039520 DOI: 10.1007/s11739-023-03529-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 12/30/2023] [Indexed: 04/24/2024]
Abstract
Renal function is associated with cardiovascular outcomes and mortality. Among equations used to eGFR, CKD-EPI equations show more accurate association with cardiovascular risk and mortality than MDRD. Recently, new CKD-EPI equations were proposed which do not include race and would be considered sufficiently accurate to estimate eGFR in clinical practice. It is unknown if these new race-free equations are comparably well associated with cardiovascular outcomes in high-risk individuals. The analysis was performed in the AtheroGene Study cohort including patients at high cardiovascular risk. eGFR was determined using the established as well as the recently developed formulas which are calculated without the otherwise existing coefficient for black race. The outcome was cardiovascular death. Analyses included Cox-proportional hazard regression and area-under-the-curve calculation. The analysis included 2089 patients followed up for a median of 3.8 years with a maximum of 6.9 years, corresponding to an overall period of 7701 patient-years. Cardiovascular death occurred in 93 (4.45%), corresponding to an annualized rate of 1.2/100 person-years. In all Cox regression analyses, the estimated adjusted GFR was an independent predictor of cardiovascular death. The equations which included cystatin C showed higher C-index compared to those which did not include cystatin C (0.75-0.76 vs. 0.71, respectively). The equations for the estimation of eGFR which include cystatin C are better associated with cardiovascular death compared to the race-free equations which include only creatinine. This finding adds on the related literature which supports the elimination of race in GFR-estimating equations, and promotion of the use of cystatin C.
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Affiliation(s)
- George Ntaios
- Department of Internal Medicine, School of Health Sciences, University of Thessaly, 41110, Larissa, Greece.
| | - Jan Brederecke
- Department of Cardiology, University Center of Cardiovascular Science, University Heart and Vascular Center Hamburg-Eppendorf, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Francisco M Ojeda
- Department of Cardiology, University Center of Cardiovascular Science, University Heart and Vascular Center Hamburg-Eppendorf, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tanja Zeller
- Department of Cardiology, University Center of Cardiovascular Science, University Heart and Vascular Center Hamburg-Eppendorf, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site, Hamburg, Germany
| | - Stefan Blankenberg
- Department of Cardiology, University Center of Cardiovascular Science, University Heart and Vascular Center Hamburg-Eppendorf, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site, Hamburg, Germany
| | - Renate B Schnabel
- Department of Cardiology, University Center of Cardiovascular Science, University Heart and Vascular Center Hamburg-Eppendorf, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site, Hamburg, Germany
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Gutiérrez OM, Sang Y, Grams ME, Ballew SH, Surapaneni A, Matsushita K, Go AS, Shlipak MG, Inker LA, Eneanya ND, Crews DC, Powe NR, Levey AS, Coresh J. Association of Estimated GFR Calculated Using Race-Free Equations With Kidney Failure and Mortality by Black vs Non-Black Race. JAMA 2022; 327:2306-2316. [PMID: 35667006 PMCID: PMC9171658 DOI: 10.1001/jama.2022.8801] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 05/11/2022] [Indexed: 12/14/2022]
Abstract
Importance At a given estimated glomerular filtration rate (eGFR), individuals who are Black have higher rates of mortality and kidney failure with replacement therapy (KFRT) compared with those who are non-Black. Whether the recently adopted eGFR equations without race preserve racial differences in risk of mortality and KFRT at a given eGFR is unknown. Objective To assess whether eGFR equations with and without race and cystatin C document racial differences in risk of KFRT and mortality in populations including Black and non-Black participants. Design, Setting, and Participants Retrospective individual-level data analysis of 62 011 participants from 5 general population and 3 chronic kidney disease (CKD) US-based cohorts with serum creatinine, cystatin C, and follow-up for KFRT and mortality from 1988 to 2018. Exposures Chronic Kidney Disease Epidemiology Collaboration equation with serum creatinine (eGFRcr with and without race), cystatin C (eGFRcys without race), or both markers (eGFRcr-cys without race). Main Outcomes and Measures The prevalence of decreased eGFR at baseline and hazard ratios of KFRT and mortality in Black vs non-Black participants were calculated, adjusted for age and sex. Analyses were performed within each cohort and with random-effect meta-analyses of the models. Results Among 62 011 participants (20 773 Black and 41 238 non-Black; mean age, 63 years; 53% women), the prevalence ratio (95% CI; percent prevalences) of eGFR less than 60 mL/min/1.73 m2 comparing Black with non-Black participants was 0.98 (95% CI, 0.93-1.03; 11% vs 12%) for eGFRcr with race, 0.95 (95% CI, 0.91-0.98; 17% vs 18%) for eGFRcys, and 1.2 (95% CI, 1.2-1.3; 13% vs 11%) for eGFRcr-cys but was 1.8 (95% CI, 1.7-1.8; 15% vs 9%) for eGFRcr without race. During a mean follow-up of 13 years, 8% and 4% of Black and non-Black participants experienced KFRT and 34% and 39% died, respectively. Decreased eGFR was associated with significantly greater risk of both outcomes for all equations. At an eGFR of 60 mL/min/1.73 m2, the hazard ratios for KFRT comparing Black with non-Black participants were 2.8 (95% CI, 1.6-4.9) for eGFRcr with race, 3.0 (95% CI, 1.5-5.8) for eGFRcys, and 2.8 (95% CI, 1.4-5.4) for eGFRcr-cys vs 1.3 (95% CI, 0.8-2.1) for eGFRcr without race. The 5-year absolute risk differences for KFRT comparing Black with non-Black participants were 1.4% (95% CI, 0.2%-2.6%) for eGFRcr with race, 1.1% (95% CI, 0.2%-1.9%) for eGFRcys, and 1.3% (95% CI, 0%-2.6%) for eGFRcr-cys vs 0.37% (95% CI, -0.32% to 1.05%) for eGFRcr without race. Similar patterns were observed for mortality. Conclusions and Relevance In this retrospective analysis of 8 US cohorts including Black and non-Black individuals, the eGFR equation without race that included creatinine and cystatin C, but not the eGFR equation without race that included creatinine without cystatin C, demonstrated racial differences in the risk of KFRT and mortality throughout the range of eGFR. The eGFRcr-cys equation may be preferable to the eGFRcr equation without race for assessing racial differences in the risk of KFRT and mortality associated with low eGFR.
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Affiliation(s)
| | - Yingying Sang
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Morgan E. Grams
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Shoshana H. Ballew
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Aditya Surapaneni
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Kunihiro Matsushita
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Alan S. Go
- Division of Research, Kaiser Permanente Northern California, Oakland
| | - Michael G. Shlipak
- Kidney Health Research Collaborative, San Francisco Veterans Affairs Medical Center, University of California, San Francisco
| | - Lesley A. Inker
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | - Nwamaka D. Eneanya
- Renal-Electrolyte and Hypertension Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia
| | - Deidra C. Crews
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Neil R. Powe
- Department of Medicine, Zuckerberg San Francisco General Hospital, University of California, San Francisco
| | - Andrew S. Levey
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | - Josef Coresh
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health and the Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland
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4
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Hsu CY, Yang W, Parikh RV, Anderson AH, Chen TK, Cohen DL, He J, Mohanty MJ, Lash JP, Mills KT, Muiru AN, Parsa A, Saunders MR, Shafi T, Townsend RR, Waikar SS, Wang J, Wolf M, Tan TC, Feldman HI, Go AS. Race, Genetic Ancestry, and Estimating Kidney Function in CKD. N Engl J Med 2021; 385:1750-1760. [PMID: 34554660 PMCID: PMC8994696 DOI: 10.1056/nejmoa2103753] [Citation(s) in RCA: 134] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND The inclusion of race in equations to estimate the glomerular filtration rate (GFR) has become controversial. Alternative equations that can be used to achieve similar accuracy without the use of race are needed. METHODS In a large national study involving adults with chronic kidney disease, we conducted cross-sectional analyses of baseline data from 1248 participants for whom data, including the following, had been collected: race as reported by the participant, genetic ancestry markers, and the serum creatinine, serum cystatin C, and 24-hour urinary creatinine levels. RESULTS Using current formulations of GFR estimating equations, we found that in participants who identified as Black, a model that omitted race resulted in more underestimation of the GFR (median difference between measured and estimated GFR, 3.99 ml per minute per 1.73 m2 of body-surface area; 95% confidence interval [CI], 2.17 to 5.62) and lower accuracy (percent of estimated GFR within 10% of measured GFR [P10], 31%; 95% CI, 24 to 39) than models that included race (median difference, 1.11 ml per minute per 1.73 m2; 95% CI, -0.29 to 2.54; P10, 42%; 95% CI, 34 to 50). The incorporation of genetic ancestry data instead of race resulted in similar estimates of the GFR (median difference, 1.33 ml per minute per 1.73 m2; 95% CI, -0.12 to 2.33; P10, 42%; 95% CI, 34 to 50). The inclusion of non-GFR determinants of the serum creatinine level (e.g., body-composition metrics and urinary excretion of creatinine) that differed according to race reported by the participants and genetic ancestry did not eliminate the misclassification introduced by removing race (or ancestry) from serum creatinine-based GFR estimating equations. In contrast, the incorporation of race or ancestry was not necessary to achieve similarly statistically unbiased (median difference, 0.33 ml per minute per 1.73 m2; 95% CI, -1.43 to 1.92) and accurate (P10, 41%; 95% CI, 34 to 49) estimates in Black participants when GFR was estimated with the use of cystatin C. CONCLUSIONS The use of the serum creatinine level to estimate the GFR without race (or genetic ancestry) introduced systematic misclassification that could not be eliminated even when numerous non-GFR determinants of the serum creatinine level were accounted for. The estimation of GFR with the use of cystatin C generated similar results while eliminating the negative consequences of the current race-based approaches. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.).
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Affiliation(s)
- Chi-Yuan Hsu
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Wei Yang
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Rishi V Parikh
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Amanda H Anderson
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Teresa K Chen
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Debbie L Cohen
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Jiang He
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Madhumita J Mohanty
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - James P Lash
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Katherine T Mills
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Anthony N Muiru
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Afshin Parsa
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Milda R Saunders
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Tariq Shafi
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Raymond R Townsend
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Sushrut S Waikar
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Jianqiao Wang
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Myles Wolf
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Thida C Tan
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Harold I Feldman
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
| | - Alan S Go
- From the Division of Nephrology, Department of Medicine (C.H., A.N.M., A.S.G.), and the Departments of Epidemiology and Biostatistics (A.S.G.), University of California, San Francisco, San Francisco, the Division of Research, Kaiser Permanente Northern California, Oakland (C.H., R.V.P., T.C.T., A.S.G.), the Department of Health Systems Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena (A.S.G.), and the Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Palo Alto (A.S.G.) - all in California; the Department of Biostatistics, Epidemiology, and Informatics and the Center for Clinical Epidemiology and Biostatistics (W.Y., J.W., H.I.F.), the Division of Division of Renal-Electrolyte and Hypertension (D.L.C.), and the Department of Medicine (R.R.T.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia; the Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine (A.H.A., J.H., K.T.M.) and the Tulane University Translational Science Institute (A.H.A., J.H., K.T.M.), New Orleans; the Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, and the Welch Center for Prevention, Epidemiology, and Clinical Research, Baltimore (T.K.C.), and the Division of Kidney, Urologic, and Hematologic Diseases, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda (A.P.) - all in Maryland; the Division of Nephrology, Department of Internal Medicine, Wayne State University, Detroit (M.J.M.); the Division of Nephrology, Department of Medicine, University of Illinois at Chicago (J.P.L.), and the Section of General Internal Medicine, Department of Medicine, University of Chicago (M.R.S.) - both in Chicago; the Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, Jackson (T.S.); the Section of Nephrology, Boston University School of Medicine and Boston Medical Center, Boston (S.S.W.); and the Division of Nephrology, Department of Medicine, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (M.W.)
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5
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Inker LA, Couture SJ, Tighiouart H, Abraham AG, Beck GJ, Feldman HI, Greene T, Gudnason V, Karger AB, Eckfeldt JH, Kasiske BL, Mauer M, Navis G, Poggio ED, Rossing P, Shlipak MG, Levey AS. A New Panel-Estimated GFR, Including β 2-Microglobulin and β-Trace Protein and Not Including Race, Developed in a Diverse Population. Am J Kidney Dis 2021; 77:673-683.e1. [PMID: 33301877 PMCID: PMC8102017 DOI: 10.1053/j.ajkd.2020.11.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/10/2020] [Indexed: 12/20/2022]
Abstract
RATIONALE AND OBJECTIVE Glomerular filtration rate (GFR) estimation based on creatinine and cystatin C (eGFRcr-cys) is more accurate than estimated GFR (eGFR) based on creatinine or cystatin C alone (eGFRcr or eGFRcys, respectively), but the inclusion of creatinine in eGFRcr-cys requires specification of a person's race. β2-Microglobulin (B2M) and β-trace protein (BTP) are alternative filtration markers that appear to be less influenced by race than creatinine is. STUDY DESIGN Study of diagnostic test accuracy. SETTING AND PARTICIPANTS Development in a pooled population of 7 studies with 5,017 participants with and without chronic kidney disease. External validation in a pooled population of 7 other studies with 2,245 participants. TESTS COMPARED Panel eGFR using B2M and BTP in addition to cystatin C (3-marker panel) or creatinine and cystatin C (4-marker panel) with and without age and sex or race. OUTCOMES GFR measured as the urinary clearance of iothalamate, plasma clearance of iohexol, or plasma clearance of [51Cr]EDTA. RESULTS Mean measured GFRs were 58.1 and 83.2 mL/min/1.73 m2, and the proportions of Black participants were 38.6% and 24.0%, in the development and validation populations, respectively. In development, addition of age and sex improved the performance of all equations compared with equations without age and sex, but addition of race did not further improve the performance. In validation, the 4-marker panels were more accurate than the 3-marker panels (P < 0.001). The 3-marker panel without race was more accurate than eGFRcys (percentage of estimates greater than 30% different from measured GFR [1 - P30] of 15.6% vs 17.4%; P = 0.01), and the 4-marker panel without race was as accurate as eGFRcr-cys (1 - P30 of 8.6% vs 9.4%; P = 0.2). Results were generally consistent across subgroups. LIMITATIONS No representation of participants with severe comorbid illness and from geographic areas outside of North America and Europe. CONCLUSIONS The 4-marker panel eGFR is as accurate as eGFRcr-cys without requiring specification of race. A more accurate race-free eGFR could be an important advance.
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Affiliation(s)
- Lesley A Inker
- Division of Nephrology, Tufts Medical Center; Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA.
| | - Sara J Couture
- Division of Nephrology, Tufts Medical Center; Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA
| | - Hocine Tighiouart
- Institute for Clinical Research and Health Policy Studies, Tufts Medical Center; Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA; Tufts Medical Center; Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA
| | - Alison G Abraham
- Department of Epidemiology, John Hopkins Bloomberg School of Public Health, Baltimore, MD
| | - Gerald J Beck
- Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH
| | - Harold I Feldman
- Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, Philadelphia, PA
| | - Tom Greene
- Department of Internal Medicine, University of Utah Health, Salt Lake City, UT
| | - Vilmundur Gudnason
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland; Icelandic Heart Association, Kopavogur, Iceland
| | - Amy B Karger
- Departments of Laboratory Medicine and Pathology, University of Minnesota; Department of Medicine, Hennepin County Medical Center, Minneapolis, MN
| | - John H Eckfeldt
- Departments of Laboratory Medicine and Pathology, University of Minnesota; Department of Medicine, Hennepin County Medical Center, Minneapolis, MN
| | - Bertram L Kasiske
- University of Minnesota; Department of Medicine, Hennepin County Medical Center, Minneapolis, MN
| | - Michael Mauer
- Medicine, University of Minnesota; Department of Medicine, Hennepin County Medical Center, Minneapolis, MN
| | - Gerjan Navis
- Faculty of Medical Sciences, University Medical Center Groningen, Groningen, The Netherlands
| | - Emilio D Poggio
- Department of Nephrology and Hypertension, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH
| | - Peter Rossing
- Steno Diabetes Center Copenhagen and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Michael G Shlipak
- Kidney Health Research Collaborative, San Francisco Veterans Affairs Medical Center, University of California, San Francisco, CA
| | - Andrew S Levey
- Division of Nephrology, Tufts Medical Center; Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA
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6
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Wang Y, Levey AS, Inker LA, Jessani S, Bux R, Samad Z, Khan AR, Karger AB, Allen JC, Jafar TH. Performance and Determinants of Serum Creatinine and Cystatin C-Based GFR Estimating Equations in South Asians. Kidney Int Rep 2021; 6:962-975. [PMID: 33912746 PMCID: PMC8071622 DOI: 10.1016/j.ekir.2021.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION The creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimated glomerular filtration rate (eGFR) equation was calibrated for the general Pakistan population (eGFRcr-PK) to eliminate bias and improve accuracy. Cystatin C-based CKD-EPI equations (eGFRcys and eGFRcr-cys) have not been assessed in this population, and non-GFR determinants of cystatin C are unknown. METHODS We assessed eGFRcys, eGFRcr-cys, and non-GFR determinants of cystatin C in a cross-sectional study of 557 participants (≥40 years of age) from Pakistan. We compared bias (median difference in measured GFR [mGFR] and eGFR), precision (interquartile range [IQR] of differences), accuracy (percentage of eGFR within 30% of mGFR), root mean square error (RMSE), and classification of mGFR <60 ml/min/1.73 m2 (area under the receiver operating characteristic curve [AUC] and net reclassification index [NRI]) among eGFR equations. RESULTS We found that eGFRcys underestimated mGFR (bias, 12.7 ml/min/1.73 m2 [95% confidence interval {CI} 10.7-15.2]). eGFRcr-cys did not improve performance over eGFRcr-PK in precision (P = 0.52), accuracy (P = 0.58), or RMSE (P = 0.49). Results were consistent among subgroups by age, sex, smoking, body mass index (BMI), and eGFR. NRI was 7.31% (95% CI 1.52%-13.1%; P < 0.001) for eGFRcr-cys versus eGFRcr-PK, but AUC was not improved (0.92 [95% CI 0.87-0.96] vs. 0.90 [95% CI 0.86-0.95]; P = 0.056). Non-GFR determinants of higher cystatin C included male sex, smoking, higher BMI and total body fat, and lower lean body mass. CONCLUSION eGFRcys underestimated mGFR in South Asians and eGFRcr-cys did not offer substantial advantage compared with eGFRcr-PK. Future studies are warranted to better understand the large bias in eGFRcys and non-GFR determinants of cystatin C in South Asians.
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Affiliation(s)
- Yeli Wang
- Program in Health Services and Systems Research, Duke–NUS Medical School, Singapore
| | - Andrew S. Levey
- Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, Massachusetts, USA
| | - Lesley A. Inker
- Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, Massachusetts, USA
| | - Saleem Jessani
- Department of Community Health Sciences, Aga Khan University, Karachi, Pakistan
| | - Rasool Bux
- Department of Pediatrics (Division of Women and Child Health), Aga Khan University, Karachi, Pakistan
| | - Zainab Samad
- Department of Medicine, Aga Khan University, Karachi, Pakistan
| | - Ali Raza Khan
- Department of Medicine, Aga Khan University, Karachi, Pakistan
| | - Amy B. Karger
- Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | - John C. Allen
- Center for Quantitative Medicine, Office of Clinical Sciences, Duke–NUS Medical School, Singapore
| | - Tazeen H. Jafar
- Program in Health Services and Systems Research, Duke–NUS Medical School, Singapore
- Department of Renal Medicine, Singapore General Hospital, Singapore
- Duke Global Health Institute, Duke University, Durham, North Carolina, USA
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Kang E, Han SS, Kim J, Park SK, Chung W, Oh YK, Chae DW, Kim YS, Ahn C, Oh KH. Discrepant glomerular filtration rate trends from creatinine and cystatin C in patients with chronic kidney disease: results from the KNOW-CKD cohort. BMC Nephrol 2020; 21:280. [PMID: 32677901 PMCID: PMC7364655 DOI: 10.1186/s12882-020-01932-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 07/06/2020] [Indexed: 11/21/2022] Open
Abstract
Background Serum creatinine (Cr) and cystatin C (CysC) can both be used to estimate glomerular filtration rate (eGFRCr and eGFRCysC). However, certain conditions may cause discrepancies between eGFR trends from Cr and CysC, and these remain undetermined in patients with chronic kidney disease (CKD). Methods A total of 1069 patients from the Korean CKD cohort (KNOW-CKD), which enrolls pre-dialytic CKD patients, whose Cr and CysC had been followed for more than 4 years were included in the sample. We performed trajectory analysis using latent class mixed modeling and identified members of the discrepancy group when patient trends between eGFRCr and eGFRCysC differed. Multivariate logistic analyses with Firth’s penalized likelihood regression models were performed to identify conditions related to the discrepancy. Results Trajectory patterns of eGFRCr were classified into three groups: two groups with stable eGFRCr (stable with high eGFRCr and stable with low eGFRCr) and one group with decreasing eGFRCr. Trajectory analysis of eGFRCysC also showed similar patterns, comprising two groups with stable eGFRCysC and one group with decreasing eGFRCysC. Patients in the discrepancy group (decreasing eGFRCr but stable & low eGFRCysC; n = 55) were younger and had greater proteinuria values than the agreement group (stable & low eGFRCr and eGFRCysC; n = 706), differences that remained consistent irrespective of the measurement period (4 or 5 years). Conclusions In the present study, we identify conditions related to discrepant trends of eGFRCr and eGFRCysC. Clinicians should remain aware of such potential discrepancies when tracing both Cr and CysC.
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Affiliation(s)
- Eunjeong Kang
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Seung Seok Han
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Jayoun Kim
- Medical Research Collaborating Center, Seoul National University College of Medicine, Seoul, South Korea
| | - Sue Kyung Park
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - Wookyung Chung
- Department of Internal Medicine, Gachon University, Gil Medical Center, Incheon, South Korea
| | - Yun Kyu Oh
- Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, South Korea
| | - Dong-Wan Chae
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Yong-Soo Kim
- Department of Internal Medicine, The Catholic University of Korea, Seoul St. Mary's Hospital, Seoul, South Korea
| | - Curie Ahn
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea.
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Yamaguchi Y, Itabashi M, Yumura W, Takei T. Geriatric assessment of estimated glomerular filtration rate: a cross-sectional study. Clin Exp Nephrol 2019; 24:216-224. [DOI: 10.1007/s10157-019-01797-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 09/27/2019] [Indexed: 12/13/2022]
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9
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Inker LA, Levey AS, Tighiouart H, Shafi T, Eckfeldt JH, Johnson C, Okparavero A, Post WS, Coresh J, Shlipak MG. Performance of glomerular filtration rate estimating equations in a community-based sample of Blacks and Whites: the multiethnic study of atherosclerosis. Nephrol Dial Transplant 2019; 33:417-425. [PMID: 28505377 DOI: 10.1093/ndt/gfx042] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/16/2017] [Indexed: 01/27/2023] Open
Abstract
Background The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are recommended for glomerular filtration rate (GFR) estimation in the general population. They have not been evaluated in community-based populations, including Blacks at higher levels of GFR, but are commonly applied in such populations. Methods In an ancillary study of Multi-Ethnic Study of Atherosclerosis conducted at one site, we evaluated the performance of the CKD-EPI equations for creatinine (eGFRcr), cystatin C (eGFRcys) or the combination (eGFRcr-cys) compared with GFR measured as plasma clearance of iohexol. Results Among 294 participants, the mean age was 71 (SD 9) years, 47% were Black, 48% were women and the mean measured GFR (mGFR) was 72.6 (SD 18.8) mL/min/1.73 m2. The CKD-EPI equations overestimated mGFR with a larger median bias for eGFRcr and eGFRcr-cys than eGFRcys [-8.3 (95% confidence interval -9.7, -6.5), -7.8 (-9.2, -6.2) and -3.7 (-5.0, -1.8) mL/min/1.73 m2, respectively], with smaller bias for those with lower compared with higher eGFR and by race compared with sex. Conclusion The small differential bias of the CKD-EPI equation between races suggests that they can be used in Blacks as well as Whites in older community-based adults. The large differential bias in women versus men in all equations is in contrast to other studies and is unexplained. Further studies are required in multiracial and multiethnic community-based cohorts, taking into account differences in GFR measurement methods.
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Affiliation(s)
- Lesley A Inker
- Division of Nephrology, Tufts Medical Center, Boston, MA, USA
| | - Andrew S Levey
- Division of Nephrology, Tufts Medical Center, Boston, MA, USA
| | - Hocine Tighiouart
- Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA, USA.,Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA, USA
| | - Tariq Shafi
- Johns Hopkins University, Baltimore, MD, USA
| | - John H Eckfeldt
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Craig Johnson
- Department of Biostatistics, School of Public Health and Community Medicine, University of Washington, Seattle, WA, USA
| | | | | | | | - Michael G Shlipak
- Division of Nephrology, University of California, San Francisco, CA, USA
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10
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Husain SA, Willey JZ, Park Moon Y, Elkind MSV, Sacco RL, Wolf M, Cheung K, Wright CB, Mohan S. Creatinine- versus cystatin C-based renal function assessment in the Northern Manhattan Study. PLoS One 2018; 13:e0206839. [PMID: 30427947 PMCID: PMC6235352 DOI: 10.1371/journal.pone.0206839] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 10/19/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Accurate glomerular filtration rate estimation informs drug dosing and risk stratification. Body composition heterogeneity influences creatinine production and the precision of creatinine-based estimated glomerular filtration rate (eGFRcr) in the elderly. We compared chronic kidney disease (CKD) categorization using eGFRcr and cystatin C-based estimated GFR (eGFRcys) in an elderly, racially/ethnically diverse cohort to determine their concordance. METHODS The Northern Manhattan Study (NOMAS) is a predominantly elderly, multi-ethnic cohort with a primary aim to study cardiovascular disease epidemiology. We included participants with concurrently measured creatinine and cystatin C. eGFRcr was calculated using the CKD-EPI 2009 equation. eGFRcys was calculated using the CKD-EPI 2012 equation. Logistic regression was used to estimate odds ratios and 95% confidence intervals of factors associated with reclassification from eGFRcr≥60ml/min/1.73m2 to eGFRcys<60ml/min/1.73m2. RESULTS Participants (n = 2988, mean age 69±10yrs) were predominantly Hispanic, female, and overweight/obese. eGFRcys was lower than eGFRcr by mean 23mL/min/1.73m2. 51% of participants' CKD status was discordant, and only 28% maintained the same CKD stage by both measures. Most participants (78%) had eGFRcr≥60mL/min/1.73m2; among these, 64% had eGFRcys<60mL/min/1.73m2. Among participants with eGFRcr≥60mL/min/1.73m2, eGFRcys-based reclassification was more likely in those with age >65 years, obesity, current smoking, white race, and female sex. CONCLUSIONS In a large, multiethnic, elderly cohort, we found a highly discrepant prevalence of CKD with eGFRcys versus eGFRcr. Determining the optimal method to estimate GFR in elderly populations needs urgent further study to improve risk stratification and drug dosing.
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Affiliation(s)
- S. Ali Husain
- Department of Medicine, Division of Nephrology, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York, United States of America
| | - Joshua Z. Willey
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Yeseon Park Moon
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Mitchell S. V. Elkind
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America
| | - Ralph L. Sacco
- Departments of Neurology and Public Health Sciences, Leonard M. Miller School of Medicine, the McKnight Brain Institute and the Neuroscience Program, University of Miami, Miami, Florida, United States of America
| | - Myles Wolf
- Department of Medicine, Division of Nephrology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Ken Cheung
- Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, New York, United States of America
| | - Clinton B. Wright
- Departments of Neurology and Public Health Sciences, Leonard M. Miller School of Medicine, the McKnight Brain Institute and the Neuroscience Program, University of Miami, Miami, Florida, United States of America
| | - Sumit Mohan
- Department of Medicine, Division of Nephrology, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York, United States of America
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York, United States of America
- * E-mail:
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Berglund DM, Zhang L, Matas AJ, Ibrahim HN. Measured Glomerular Filtration Rate After Kidney Donation: No Evidence of Accelerated Decay. Transplantation 2018; 102:1756-1761. [PMID: 29677075 PMCID: PMC6153046 DOI: 10.1097/tp.0000000000002215] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The rate of measured glomerular filtration rate (GFR) change in kidney donor years after donation has not been adequately addressed. Whether this change is accelerated in the setting of 1 kidney is also understudied. METHODS Two hundred fourteen randomly selected donors underwent serial GFR measurements of nonradioactive iohexol. Estimated GFR at each visit was calculated using the Chronic Kidney Disease Epidemiology Collaboration and Modification of Diet in Renal Disease study equations. RESULTS Glomerular filtration rate visits were 4.8 ± 1.3 years apart and the second occurring 16.9 ± 9.1 years after donation. Most (97.7%) were white, 60.8% female, and 78.5% were related to their recipient. Most, 84.6%, had a GFR of 60 mL/min per 1.73 m or higher, 14.0% had a GFR between 45 and 60 mL/min per 1.73 m, and 1.4% had a GFR less than 45 mL/min per 1.73 m. Between visits 1 and 2, 56.5% had a GFR decline, 36.0% increase, and in 7.5%, there was no change. Overall, GFR declined at a rate of -0.42 mL/min per 1.73 m per year. Of GFR estimating models, only Chronic Kidney Disease Epidemiology Collaboration-Creatinine equation produced a slope that was steeper than measured GFR. CONCLUSIONS Nearly 2 decades postdonation GFR declined at a rate similar to that seen in the general population, and in one third, GFR continues to increase.
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Affiliation(s)
| | - Lei Zhang
- Biostatistical Design and Analysis Center, University of Minnesota, Minneapolis, MN
| | - Arthur J. Matas
- Department of Surgery, University of Minnesota, Minneapolis, MN
| | - Hassan N. Ibrahim
- Division of Renal Diseases and Hypertension, Houston Methodist Hospital, Houston, TX
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Björk J, Grubb A, Gudnason V, Indridason OS, Levey AS, Palsson R, Nyman U. Comparison of glomerular filtration rate estimating equations derived from creatinine and cystatin C: validation in the Age, Gene/Environment Susceptibility-Reykjavik elderly cohort. Nephrol Dial Transplant 2018; 33:1380-1388. [PMID: 29040701 PMCID: PMC6070032 DOI: 10.1093/ndt/gfx272] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/04/2017] [Indexed: 11/15/2022] Open
Abstract
Background Validation studies comparing glomerular filtration rate (GFR) equations based on standardized creatinine and cystatin C assays in the elderly are needed. The Icelandic Age, Gene/Environment Susceptibility-Kidney cohort was used to compare two pairs of recently developed GFR equations, the revised Lund-Malmö creatinine equation (LMRCr) and the arithmetic mean of the LMRCr and Caucasian, Asian, Paediatric and Adult cystatin C equations (MEANLMR+CAPA), as well as the Full Age Spectrum creatinine equation (FASCr) and its combination with cystatin C (FASCr+Cys), with the corresponding pair of Chronic Kidney Disease Epidemiology Collaboration equations (CKD-EPICr and CKD-EPICr+Cys). Methods A total of 805 individuals, 74-93 years of age, underwent measurement of GFR (mGFR) using plasma clearance of iohexol. Four metrics were used to compare the performance of the GFR equations: bias, precision, accuracy [including the percentage of participants with estimated GFR (eGFR) within 30% of mGFR (P30)] and the ability to detect mGFR <60 mL/min/1.73 m2. Results All equations had a P30 >90%. LMRCr and FASCr yielded significantly higher precision and P30 than CKD-EPICr, while bias was significantly worse. LMRCr, FASCr and CKD-EPICr showed similar ability to detect mGFR <60 mL/min/1.73 m2 based on the area under the receiver operating characteristic curves. MEANLMR+CAPA, FASCr+Cys and CKD-EPICr+Cys all exhibited consistent improvements compared with the corresponding creatinine-based equations. Conclusion None of the creatinine-based equations was clearly superior overall in this community-dwelling elderly cohort. The addition of cystatin C improved all of the creatinine-based equations.
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Affiliation(s)
- Jonas Björk
- Clinical Studies Sweden, Forum South, Skåne University Hospital, Lund, Sweden
- Division of Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Anders Grubb
- Department of Clinical Chemistry, Skåne University Hospital, Lund University, Lund, Sweden
| | - Vilmundur Gudnason
- Icelandic Heart Association, Kopavogur, Iceland
- University of Iceland, Reykjavik, Iceland
| | - Olafur S Indridason
- Division of Nephrology, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
| | - Andrew S Levey
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts, USA
| | - Runolfur Palsson
- Division of Nephrology, Landspitali–The National University Hospital of Iceland, Reykjavik, Iceland
- University of Iceland, Reykjavik, Iceland
| | - Ulf Nyman
- Department of Translational Medicine, Division of Medical Radiology, Lund University, Malmö, Sweden
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13
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Huang N, Foster MC, Mitchell GF, Andresdottir MB, Eiriksdottir G, Gudmundsdottir H, Harris TB, Launer LJ, Palsson R, Gudnason V, Levey AS, Inker LA. Aortic stiffness and change in glomerular filtration rate and albuminuria in older people. Nephrol Dial Transplant 2017; 32:677-684. [PMID: 27190377 DOI: 10.1093/ndt/gfw050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 02/18/2016] [Indexed: 01/12/2023] Open
Abstract
Background Aortic stiffness increases with age and increases pulsatile stress in the microcirculation. Abnormalities in kidney microvascular structure and function may contribute to development or progression of chronic kidney disease in older people. Methods We performed a longitudinal analysis of 629 community-dwelling elderly Icelandic adults from the Age, Gene/Environment Susceptibility-Reykjavik Study with two visits over a mean follow-up of 5.3 years. We evaluated the associations of carotid-femoral pulse wave velocity (CFPWV), carotid pulse pressure (CPP) and augmentation index (AI), with the change in estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio (UACR) assessed as annual change and dichotomized as large changes. Models were adjusted for age, sex, height, heart rate, traditional cardiovascular disease risk factors and baseline kidney measures. Results When eGFR was analyzed as a continuous variable, higher baseline CFPWV and CPP, but not AI, were significantly associated with a larger annual decline in eGFR in models adjusted for age, sex, height, heart rate and baseline eGFR, but not after additional adjustment for the mean arterial pressure. When eGFR was analyzed as a categorical variable, higher CFPWV was significantly associated with a decrease in eGFR of ≥3 mL/min/1.73 m 2 /year [odds ratio (OR) 1.53, 95% confidence interval (CI) 1.11-2.13] and higher AI was associated with 30% eGFR decline during follow-up (OR 1.44 and 95% CI 1.03-2.00) in fully adjusted models. None of the tonometry measures was associated with change in UACR. Conclusions Abnormalities in vascular health may play a role in large declines in eGFR beyond the traditional cardiovascular disease risks in this older Icelandic cohort.
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Affiliation(s)
- Naya Huang
- The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | | | | | | | | | - Hrefna Gudmundsdottir
- Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland.,University of Iceland, Reykjavik, Iceland
| | | | | | - Runolfur Palsson
- Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland.,University of Iceland, Reykjavik, Iceland
| | - Vilmundur Gudnason
- Icelandic Heart Association, Kopavogur, Iceland.,University of Iceland, Reykjavik, Iceland
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Abstract
Chronic kidney disease (CKD) is currently defined by abnormalities of kidney structure or function assessed using a matrix of variables - including glomerular filtration rate (GFR), thresholds of albuminuria and duration of injury - and is considered by many to be a common disorder globally. However, estimates of CKD prevalence vary widely, both within and between countries. The reasons for these variations are manifold, and include true regional differences in CKD prevalence, vagaries of using estimated GFR (eGFR) for identifying CKD, issues relating to the use of set GFR thresholds to define CKD in elderly populations, and concerns regarding the use of one-off testing for assessment of eGFR or albuminuria to define the prevalence of CKD in large-scale epidemiological studies. Although CKD is common, the suggestion that its prevalence is increasing in many countries might not be correct. Here, we discuss the possible origins of differences in estimates of CKD prevalence, and present possible solutions for tackling the factors responsible for the reported variations in GFR measurements. The strategies we discuss include approaches to improve testing methodologies for more accurate assessment of GFR, to improve awareness of factors that can alter GFR readouts, and to more accurately stage CKD in certain populations, including the elderly.
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15
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He M, Ke PF, Xu JH, Chen WY, Lin HB, Zhang C, Wang YX, Zhuang JH, Huang XZ. Performance evaluation of the Sysmex Cystatin C assay on the Roche Modular P Analyzer. Clin Biochem 2016; 49:915-8. [DOI: 10.1016/j.clinbiochem.2016.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 04/07/2016] [Accepted: 04/26/2016] [Indexed: 11/29/2022]
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16
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Cystatin C standardization decreases assay variation and improves assessment of glomerular filtration rate. Clin Chim Acta 2016; 456:115-121. [PMID: 26947968 DOI: 10.1016/j.cca.2016.03.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/02/2016] [Accepted: 03/02/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND Cystatin C is increasingly used in glomerular filtration rate (GFR) estimation equations. The dependence of cystatin C results upon the analytical method has been a major source of controversy. METHODS Cystatin C was measured with non-standardized turbidimetric Roche Generation 1 and standardized nephelometric Siemens assays in 3666 and additionally with standardized Roche Generation 2 and Siemens in 567 blood samples of the Berlin Initiative Study. Cystatin C-based GFR was assessed with CKD-EPIcys (Chronic Kidney Disease Epidemiology) and CAPA (Caucasian, Asian, Pediatric, Adult) equations and the impact of the assays on GFR estimation was determined. Equation performance compared to measured GFR was evaluated. RESULTS Concordance of Roche Gen2 and Siemens was high with median difference of 0.003 ± 0.13 mg/L (limits of agreement: -0.12 to 0.12) and Passing Bablok correlation was essentially perfect. Roche Gen1 assay showed worse concordance with Siemens: median difference was 0.08 ± 0.13 mg/L (limits of agreement: -0.18 to 0.34) and correlation was inferior. Mean difference (± SD) of estimated GFRCKD-EPIcys was 0 ± 4 mL/min/1.73 m(2) for Gen2 and Siemens compared to -5 ± 8 with Gen1. Performance of GFR estimating equations was not influenced by the choice of Siemens or Gen2 assays. CONCLUSIONS Standardization of Roche Gen2 assay improved accuracy of cystatin C measurement compared to Siemens. It suggests only negligible method bias and results in equal performance of both assays when estimating GFR indicating that successful calibration has led to major progress in cystatin C analysis.
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Bansal N, Lin F, Vittinghoff E, Peralta C, Lima J, Kramer H, Shlipak M, Bibbins-Domingo K. Estimated GFR and Subsequent Higher Left Ventricular Mass in Young and Middle-Aged Adults With Normal Kidney Function: The Coronary Artery Risk Development in Young Adults (CARDIA) Study. Am J Kidney Dis 2016; 67:227-34. [PMID: 26253992 PMCID: PMC4724527 DOI: 10.1053/j.ajkd.2015.06.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 06/22/2015] [Indexed: 12/31/2022]
Abstract
BACKGROUND Left ventricular hypertrophy is common and is associated with cardiovascular events and death among patients with known chronic kidney disease. However, the link between reduced glomerular filtration rate (GFR) and left ventricular mass index (LVMI) remains poorly explored among young and middle-aged adults with preserved kidney function. In this study, we examined the association of cystatin C-based estimated GFR (eGFRcys) and rapid decline in eGFR with subsequent LVMI. STUDY DESIGN Observational study. SETTING & PARTICIPANTS We included 2,410 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort with eGFRcys > 60mL/min/1.73m(2) at year 15 and who had an echocardiogram obtained at year 25. PREDICTOR eGFRcys at year 15 and rapid decline in eGFRcys (defined as >3% per year over 5 years from years 15 to 20). OUTCOME LVMI measured at year 25. MEASUREMENTS We adjusted for age, sex, race, diabetes, body mass index, low- and high-density lipoprotein cholesterol levels, cumulative systolic blood pressure, and albuminuria. RESULTS Mean age was 40±4 (SD) years, 58% were women, and 43% were black. After 10 years of follow-up, mean LVMI was 39.6±13.4g/m(2.7). Compared with eGFRcys > 90mL/min/1.73m(2) (n = 2,228), eGFRcys of 60 to 75mL/min/1.73m(2) (n = 29) was associated with 5.63 (95% CI, 0.90-10.36) g/m(2.7) greater LVMI (P = 0.02), but there was no association of eGFRcys of 76 to 90mL/min/1.73m(2) (n = 153) with LVMI after adjustment for confounders. Rapid decline in eGFRcys was associated with higher LVMI compared with participants without a rapid eGFRcys decline (β coefficient, 1.48; 95% CI, 0.11-2.83; P = 0.03) after adjustment for confounders. LIMITATIONS There were a limited number of participants with eGFRcys of 60 to 90mL/min/1.73m(2). CONCLUSIONS Among young and middle-aged adults with preserved kidney function, eGFRcys of 60 to 75mL/min/1.73m(2) and rapid decline in eGFRcys were significantly associated with subsequently higher LVMI. Further studies are needed to understand the mechanisms that contribute to elevated LVMI in this range of eGFRcys.
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Affiliation(s)
- Nisha Bansal
- University of Washington, Kidney Research Institute, Seattle, WA.
| | - Feng Lin
- University of California, San Francisco, CA
| | | | | | - Joao Lima
- Johns Hopkins University, Baltimore, MD
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18
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Okparavero A, Foster MC, Tighiouart H, Gudnason V, Indridason O, Gudmundsdottir H, Eiriksdottir G, Gudmundsson EF, Inker LA, Levey AS. Prevalence and complications of chronic kidney disease in a representative elderly population in Iceland. Nephrol Dial Transplant 2015; 31:439-47. [PMID: 26519958 DOI: 10.1093/ndt/gfv370] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 09/29/2015] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Chronic kidney disease (CKD) is common in the elderly, but data are limited on the distribution of glomerular filtration rate (GFR) and albuminuria and the prevalence of CKD and related complications in this population. METHODS A cross-sectional study of 3173 older Icelandic adults [42% men; mean (standard deviation, SD) age of 80 (5) years] was performed to examine the distribution of estimated glomerular filtration rate (eGFR) from creatinine and cystatin C, the albumin-to-creatinine ratio (ACR), and CKD-related metabolic complications (hyperparathyroidism, anemia, hypoalbuminemia, increased anion gap, acidosis, hyperphosphatemia and hyperkalemia). RESULTS There was substantial variability in eGFR [mean (SD) 64 (18) mL/min/1.73 m(2)] and ACR [median (interquartile range) 8 (5, 17) mg/g]. The prevalence (95% confidence interval) of reduced eGFR (<60 mL/min/1.73 m(2)), albuminuria (ACR >30 mg/g) and CKD (either reduced eGFR or albuminuria) was 40% (38-41), 14% (12-15) and 45% (43-47), respectively. The prevalence of complications was higher among those with versus without CKD: hyperparathyroidism (38 versus 15%), anemia (26 versus 14%), hypoalbuminemia (19 versus 13%), increased anion gap (9 versus 5%), acidosis (5 versus 1%); (P ≤ 0.02 for all), except hyperphosphatemia (1 versus 1%) and hyperkalemia (0% overall). CONCLUSIONS The burden of CKD and CKD-related complications is high among community dwelling elderly Icelandic adults. The wide range of eGFR and ACR suggests heterogeneity in processes leading to CKD and that factors beyond aging contribute to the development of CKD in the elderly.
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Affiliation(s)
| | | | - Hocine Tighiouart
- The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA, USA Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA, USA
| | - Vilmundur Gudnason
- Icelandic Heart Association, Kopavogur, Iceland University of Iceland, Reykjavik, Iceland
| | - Olafur Indridason
- Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland
| | - Hrefna Gudmundsdottir
- University of Iceland, Reykjavik, Iceland Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland
| | | | | | - Lesley A Inker
- Division of Nephrology, Tufts Medical Center, Boston, MA, USA
| | - Andrew S Levey
- Division of Nephrology, Tufts Medical Center, Boston, MA, USA
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19
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Abstract
The American Diabetes Association recommends annual assessment of glomerular filtration rate (GFR) to screen for diabetic nephropathy. GFR is measured indirectly using markers that, ideally, are eliminated only by glomerular filtration. Measured GFR, although the gold standard, remains cumbersome and expensive. GFR is therefore routinely estimated using creatinine and/or cystatin C and clinical variables. In pediatrics, the Schwartz creatinine-based equation is most frequently used even though combined creatinine and cystatin C-based equations demonstrate stronger agreement with measured GFR. In adults, the CKD Epidemiology Collaboration (CKD-EPI) equations with creatinine and/or cystatin C are the most accurate and precise estimating equations. Despite recent advances, current estimates of GFR lack precision and accuracy before chronic kidney disease stage 3 (GFR < 60 mL/min/1.73 m(2)). There is therefore an urgent need to improve the methods for estimating and measuring GFR. In this review, we examine the current literature and data addressing measurement and estimation of GFR in diabetes.
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Affiliation(s)
- Petter Bjornstad
- Department of Pediatric Endocrinology, University of Colorado School of Medicine, Aurora, CO, USA,
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20
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Berg UB, Nyman U, Bäck R, Hansson M, Monemi KÅ, Herthelius M, Björk J. New standardized cystatin C and creatinine GFR equations in children validated with inulin clearance. Pediatr Nephrol 2015; 30:1317-26. [PMID: 25903639 DOI: 10.1007/s00467-015-3060-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/17/2015] [Accepted: 01/27/2015] [Indexed: 11/27/2022]
Abstract
BACKGROUND This study compares glomerular filtration rate (GFR) equations in children based on standardized cystatin C (CYSC) and creatinine (CREA) and their combinations with renal clearance of inulin (C-inulin). METHODS A total of 220 children with different renal disorders were referred for C-inulin (median 84 ml/min/1.73 m(2)). Bias, precision (interquartile range, IQR), and accuracy (percentage of estimates ±30 % of C-inulin; P30) were evaluated for two cystatin C equations, CAPACYSC and BergCYSC, for creatinine equations, SchwartzCREA and GaoCREA, the arithmetic mean of CAPACYSC and SchwartzCREA (MEANCAPA+Schwartz), BergCYSC and SchwartzCREA (MEANBERG+SCHWARTZ) and the composite equation ChehadeCYSC+CREA. RESULTS Overall results of CAPACYSC, BergCYSC, SchwartzCREA, GaoCREA, MEANCAPA+Schwartz, MEANBERG+SCHWARTZ and ChehadeCYSC+CREA were: median bias -7.6/-4.9/-3.7/-2.3/-4.6/-4.0/-10.1 %, IQR 20.0/19.9/21.7/22.4/21.0/20.9/23.3 ml/min/1.73 m(2) and P30 86/86/80/83/89/91/83 %. The cystatin C equations, MEANCAPA+Schwartz and MEANBERG+SCHWARTZ had a more stable performance across subgroups compared with SchwartzCREA, GaoCREA and ChehadeCYSC+CREA. CONCLUSIONS Cystatin C was the preferred filtration marker for GFR estimation in children, while the benefit of combining cystatin C and creatinine deserves further investigations.
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Affiliation(s)
- Ulla B Berg
- Department of Clinical Science, Intervention and Technology, Division of Pediatrics, Karolinska Institutet, Karolinska University Hospital Huddinge, 14186, Stockholm, Sweden,
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Perrin NES, Berg UB. Estimated glomerular filtration rates cannot replace measured GFR in type 1 diabetes patients with hyperfiltration. Acta Paediatr 2015; 104:730-7. [PMID: 25739704 DOI: 10.1111/apa.12993] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 01/08/2015] [Accepted: 03/02/2015] [Indexed: 01/02/2023]
Abstract
AIM This study of children and young adults with type 1 diabetes with normal to high glomerular filtration rates (GFR) compared estimated GFR (eGFR) with measured GFR (mGFR). METHODS GFR was measured by inulin clearance, and we carried out simultaneous analyses of standardised creatinine and cystatin C. eGFR was calculated using different formulas. RESULTS We enrolled 106 patients, including 56 males, aged 21.9 (standard deviation 9.2) years with 13.7 (9.1) years' duration of diabetes and a mean haemoglobin A1c (HbA1c ) of 7.7% (61 mmol/mol). The median mGFR was 128 (111-143) mL/min/1.73 m(2) . Most of the eGFR estimations failed to detect a significant proportion of hyperfiltration based on inulin clearance. The best accuracy (P30) between eGFR and mGFR was seen with eGFRCKD - EPI (92%), eGFRcys C Berg (86%), eGFRcys C CAPA (78%) and eGFRcys C Inker (84%) where eGFRCKD - EPI and eGFR cys C Berg showed the lowest bias. Most eGFRcys C measurements showed greater accuracy when combined with eGFRcr (P30 92-94%). CONCLUSION The best accuracy (P30) and lowest bias were found with eGFRCKD - EPI and eGFR Berg. in this cohort. However, eGFR cannot accurately replace mGFR to detect hyperfiltration and follow GFR over time in young patients with type 1 diabetes.
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Affiliation(s)
- NES Perrin
- Department of Clinical Science; Intervention and Technology; Division of Peadiatrics; Karolinska Institutet; Karolinska University Hospital; Stockholm Sweden
| | - UB Berg
- Department of Clinical Science; Intervention and Technology; Division of Peadiatrics; Karolinska Institutet; Karolinska University Hospital; Stockholm Sweden
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Nyman U, Björk J, Bäck SE, Sterner G, Grubb A. Estimating GFR prior to contrast medium examinations—what the radiologist needs to know! Eur Radiol 2015; 26:425-35. [DOI: 10.1007/s00330-015-3842-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 05/05/2015] [Accepted: 05/11/2015] [Indexed: 11/25/2022]
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Eckfeldt JH, Karger AB, Miller WG, Rynders GP, Inker LA. Performance in Measurement of Serum Cystatin C by Laboratories Participating in the College of American Pathologists 2014 CYS Survey. Arch Pathol Lab Med 2015; 139:888-93. [PMID: 25884370 DOI: 10.5858/arpa.2014-0427-cp] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT Cystatin C is becoming an increasingly popular biomarker for estimating glomerular filtration rate, and accurate measurements of cystatin C concentrations are necessary for accurate estimates of glomerular filtration rate. OBJECTIVE To assess the accuracy of cystatin C concentration measurements in laboratories participating in the College of American Pathologists CYS Survey. DESIGN Two fresh frozen serum pools, the first from apparently healthy donors and the second from patients with chronic kidney disease, were prepared and distributed to laboratories participating in the CYS Survey along with the 2 usual processed human plasma samples. Target values were established for each pool by using 2 immunoassays and ERM DA471/IFCC international reference material. RESULTS For the normal fresh frozen pool (ERM-DA471/IFCC-traceable target of 0.960 mg/L), the all-method mean (SD, % coefficient of variation [CV]) reported by all of the 123 reporting laboratories was 0.894 mg/L (0.128 mg/L, 14.3%). For the chronic kidney disease pool (ERM-DA471/IFCC-traceable target of 2.37 mg/L), the all-method mean (SD, %CV) was 2.258 mg/L (0.288 mg/L, 12.8%). There were substantial method-specific biases (mean milligram per liter reported for the normal pool was 0.780 for Siemens, 0.870 for Gentian, 0.967 for Roche, 1.061 for Diazyme, and 0.970 for other/not specified reagents; and mean milligram per liter reported for the chronic kidney disease pool was 2.052 for Siemens, 2.312 for Gentian, 2.247 for Roche, 2.909 for Diazyme, and 2.413 for other/not specified reagents). CONCLUSIONS Manufacturers need to improve the accuracy of cystatin C measurement procedures if cystatin C is to achieve its full potential as a biomarker for estimating glomerular filtration rate.
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Affiliation(s)
| | | | | | | | - Lesley A Inker
- From the Department of Laboratory Medicine and Pathology (Drs Eckfeldt and Karger).,and the Advanced Research and Diagnostic Laboratory (Mr Rynders).,University of Minnesota, Minneapolis; the Department of Pathology, Virginia Commonwealth University, Richmond (Dr Miller);,and the Division of Nephrology, Tufts Medical Center, Boston, Massachusetts (Dr Inker)
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Fan L, Levey AS, Gudnason V, Eiriksdottir G, Andresdottir MB, Gudmundsdottir H, Indridason OS, Palsson R, Mitchell G, Inker LA. Comparing GFR Estimating Equations Using Cystatin C and Creatinine in Elderly Individuals. J Am Soc Nephrol 2014; 26:1982-9. [PMID: 25527647 DOI: 10.1681/asn.2014060607] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 10/06/2014] [Indexed: 12/13/2022] Open
Abstract
Current guidelines recommend reporting eGFR using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations unless other equations are more accurate, and recommend the combination of creatinine and cystatin C (eGFRcr-cys) as more accurate than either eGFRcr or eGFRcys alone. However, preferred equations and filtration markers in elderly individuals are debated. In 805 adults enrolled in the community-based Age, Gene/Environment Susceptibility (AGES)-Reykjavik Study, we measured GFR (mGFR) using plasma clearance of iohexol, standardized creatinine and cystatin C, and eGFR using the CKD-EPI, Japanese, Berlin Initiative Study (BIS), and Caucasian and Asian pediatric and adult subjects (CAPA) equations. We evaluated equation performance using bias, precision, and two measures of accuracy. We first compared the Japanese, BIS, and CAPA equations with the CKD-EPI equations to determine the preferred equations, and then compared eGFRcr and eGFRcys with eGFRcr-cys using the preferred equations. Mean (SD) age was 80.3 (4.0) years. Median (25th, 75th) mGFR was 64 (52, 73) ml/min per 1.73 m(2), and the prevalence of decreased GFR was 39% (95% confidence interval, 35.8 to 42.5). Among 24 comparisons with the other equations, CKD-EPI equations performed better in 9, similar in 13, and worse in 2. Using the CKD-EPI equations, eGFRcr-cys performed better than eGFRcr in four metrics, better than eGFRcys in two metrics, and similar to eGFRcys in two metrics. In conclusion, neither the Japanese, BIS, nor CAPA equations were superior to the CKD-EPI equations in this cohort of community-dwelling elderly individuals. Using the CKD-EPI equations, eGFRcr-cys performed better than eGFRcr or eGFRcys.
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Affiliation(s)
- Li Fan
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts; Department of Nephrology, The First Affiliated Hospital, Sun Yat-Sen University, Key Laboratory of Nephrology, Ministry of Health of China, Guangdong Provincial Key Laboratory of Nephrology, Guangzhou, China
| | - Andrew S Levey
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | - Vilmundur Gudnason
- Icelandic Heart Association, Kopavogur, Iceland; Centre for Public Health Sciences, University of Iceland, Reykjavik, Iceland
| | | | - Margret B Andresdottir
- Division of Nephrology, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland; and
| | - Hrefna Gudmundsdottir
- Centre for Public Health Sciences, University of Iceland, Reykjavik, Iceland; Division of Nephrology, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland; and
| | - Olafur S Indridason
- Division of Nephrology, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland; and
| | - Runolfur Palsson
- Centre for Public Health Sciences, University of Iceland, Reykjavik, Iceland; Division of Nephrology, Landspitali-The National University Hospital of Iceland, Reykjavik, Iceland; and
| | - Gary Mitchell
- Cardiovascular Engineering Inc., Norwood, Massachusetts
| | - Lesley A Inker
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts;
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Comparison of cystatin C and creatinine-based equations for GFR estimation after living kidney donation. Transplantation 2014; 98:871-7. [PMID: 24825515 DOI: 10.1097/tp.0000000000000129] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The performance of glomerular filtration rate (GFR) equations incorporating both cystatin C (CysC) and serum creatinine (Creat) in living kidney donors has not been studied before. METHODS From a population of 3,698 living kidney donors, 257 donors were randomly selected to undergo GFR measurement (mGFR) by the plasma disappearance of iohexol. GFR was estimated with the Modification of Diet in Renal Disease (MDRD) equation and the Chronic Kidney Disease Epidemiology Collaboration study eGFR(CKD-EPI-Creat) in 257 donors and the two newly developed equations using CysC with and without Creat, eGFR(CKD-EPI-CysC) and eGFR(CKD-EPI-Creat+CysC), in 215 donors. RESULTS Mean mGFR was 71.8±11.8 mL/min/1.73 m. The eGFR(MDRD) exhibited least and only negative bias and the three other models were comparable in terms of bias. The eGFR(CKD-EPI-Creat+CysC) equation was most precise; r=0.64. Both eGFR(MDRD) and eGFR(CKD-EPI-Creat+CysC) had high percentage (94.4% and 92.6%, respectively) of estimates falling within 30% of mGFR versus estimates by eGFR(CKD-EPI-Creat) and eGFR(CKD-EPI-CysC) equations (87.2% and 85.1%, respectively). The eGFR(MDRD) was by far most accurate in identifying those with mGFR less than 60 mL/min/1.73 m whereas the CKD-EPI models were extremely accurate in classifying those with mGFR greater than or equal to 60 mL/min/1.73 m. CONCLUSIONS eGFR(CKD-EPI-Creat+CysC) equation provides comparable accuracy to the eGFR(MDRD) in overall estimation of mGFR, but with higher precision. However, eGFR(CKD-EPI-Creat+CysC) clearly misses many of those with a post-donation GFR less than 60 mL/min/1.73 m and therefore eGFR(MDRD) is preferable in detecting donors with GFR less than 60 mL/min/1.73 m.
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González-Antuña A, Rodríguez-González P, Ohlendorf R, Henrion A, Delatour V, García Alonso JI. Determination of Cystatin C in human serum by isotope dilution mass spectrometry using mass overlapping peptides. J Proteomics 2014; 112:141-55. [PMID: 25230103 DOI: 10.1016/j.jprot.2014.09.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/21/2014] [Accepted: 09/04/2014] [Indexed: 12/23/2022]
Abstract
UNLABELLED We propose a peptide-based isotope dilution mass spectrometry approach for Cystatin C determination in human serum samples, a clinical marker for renal status for which backup by a mass spectrometry based primary method has been missing so far. In contrast to common protocols, the isotope labelled version of the proteotypic signature peptide is designed such as keeping the isotopic difference as little as possible with respect to the peptide released from the protein. Peptides labelled in two (13)C atoms are added to the serum samples just before proteolysis. After two steps of chromatographic purification the sample is measured by selected reaction monitoring using a LC-MS/MS. Resolution of the first quadrupole is reduced to transmit the whole parent ion cluster to the collision cell for monitoring accurate isotopic distributions of the molecular fragments. Molar fractions of labelled and natural abundance peptides are directly obtained from the experimental mass spectra of the in-cell fragment ions. Thus, the natural abundance protein concentration is obtained from the fragment-ion spectrum of the sample without resorting to extra calibration runs. Applicability of the approach is demonstrated by the measurement of the serum concentration of Cystatin C in Reference Material ERM R-DA471/IFCC and real samples. BIOLOGICAL SIGNIFICANCE Cystatin C is used as an alternative marker instead of, or in combination with creatinine for non-invasive determination of glomerular filtration rates. Advantages advocating in favour of Cystatin C in diagnosis of chronic kidney diseases are the lower variability of its serum level and, particularly, virtual independence on sex, age and muscle mass. However, in order to capitalize, accuracy of measurement has to be in proportion with the predictive power of the marker. Though there are label-free methods available for screening purposes or high-throughput analysis, achieving high levels of reliability and accuracy in quantitative proteomics takes reference to isotope labelled materials. Present routine assays (mainly nephelometry, turbidimetry and ligand-binding assays) are known to leave improvement to be desired in that respect. Absolute quantification based on enzymatic signature-peptides provides a method principle establishing traceability to the International System of Units on the level of primary methods. The kind of technique is capable, by this way, of high accuracy value-assignment to matrix materials needed for calibration of present routine assays, where not completely replacing them. Cystatin C measurement by isotope dilution mass spectrometry is developed in this study with the aim of making available this tool to support diagnostics of kidney function in the same way.
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Affiliation(s)
- Ana González-Antuña
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain
| | - Pablo Rodríguez-González
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain.
| | - Rudiger Ohlendorf
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Germany
| | - André Henrion
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Germany
| | - Vincent Delatour
- Laboratoire National de Métrologie et d'Essais (LNE), Paris, France(1)
| | - J Ignacio García Alonso
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Julián Clavería 8, 33006 Oviedo, Spain
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Tyrefors N, Michelsen P, Grubb A. Two new types of assays to determine protein concentrations in biological fluids using mass spectrometry of intact proteins with cystatin C in spinal fluid as an example. Scandinavian Journal of Clinical and Laboratory Investigation 2014; 74:546-54. [PMID: 25010448 PMCID: PMC4196591 DOI: 10.3109/00365513.2014.917697] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
There is no reference method that is generally acknowledged to be unbiased for the determination of the concentration of any protein in biological fluids. This is probably because mass spectrometry (MS) methods acknowledged as reference methods for determination of low molecular mass substances in biological fluids, e.g. creatinine, have been difficult to adapt for proteins. Here we suggest two tentative MS methods, which might be used as reference methods for the determination of protein concentrations in biological fluids. One is based upon the addition to the fluid of a non-proteome reference protein, very similar to the one to be measured, and analyzing the ratio between the corresponding peaks in a selected ion monitoring (SIM) chromatogram. We call this method LC-MS-NPRP (NPRP, Non-Proteome Reference Protein). The other method is based upon the classical standard addition assay for low molecular mass substances. The results of these assays for cystatin C in spinal fluid were compared to those obtained by an immunoassay. Both methods indicated lower concentration than the immunoassay. This was found to be due to the presence of a significant fraction of monohydroxylated cystatin C in spinal fluid. It turned out that the sum of the unhydroxylated and hydroxylated cystatin C concentrations, determined by either of the two MS methods, were close to the results obtained by the immunoassay. These MS-based methods analyze intact proteins and therefore seem more suitable for the determination of protein concentrations in biological fluids than other MS-based methods requiring proteolytic degradation with its inherent lack of precision.
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Affiliation(s)
- Niklas Tyrefors
- Department of Medicinal Chemistry, Analytical Pharmaceutical Chemistry, Uppsala University , Uppsala , Sweden
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Frazee EN, Rule AD, Herrmann SM, Kashani KB, Leung N, Virk A, Voskoboev N, Lieske JC. Serum cystatin C predicts vancomycin trough levels better than serum creatinine in hospitalized patients: a cohort study. Crit Care 2014; 18:R110. [PMID: 24887089 PMCID: PMC4075252 DOI: 10.1186/cc13899] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 05/06/2014] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Serum cystatin C can improve glomerular filtration rate (GFR) estimation over creatinine alone, but whether this translates into clinically relevant improvements in drug dosing is unclear. METHODS This prospective cohort study enrolled adults receiving scheduled intravenous vancomycin while hospitalized at the Mayo Clinic in 2012. Vancomycin dosing was based on weight, serum creatinine with the Cockcroft-Gault equation, and clinical judgment. Cystatin C was later assayed from the stored serum used for the creatinine-based dosing. Vancomycin trough prediction models were developed by using factors available at therapy initiation. Residuals from each model were used to predict the proportion of patients who would have achieved the target trough with the model compared with that observed with usual care. RESULTS Of 173 patients enrolled, only 35 (20%) had a trough vancomycin level within their target range (10 to 15 mg/L or 15 to 20 mg/L). Cystatin C-inclusive models better predicted vancomycin troughs than models based upon serum creatinine alone, although both were an improvement over usual care. The optimal model used estimated GFR by the Chronic Kidney Disease Epidemiology Collaborative (CKD-EPI) creatinine-cystatin C equation (R(2) = 0.580). This model is expected to yield 54% (95% confidence interval 45% to 61%) target trough attainment (P <0.001 compared with the 20% with usual care). CONCLUSIONS Vancomycin dosing based on standard care with Cockcroft-Gault creatinine clearance yielded poor trough achievement. The developed dosing model with estimated GFR from CKD-EPIcreatinine-cystatin C could yield a 2.5-fold increase in target trough achievement compared with current clinical practice. Although this study is promising, prospective validation of this or similar cystatin C-inclusive dosing models is warranted.
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Affiliation(s)
- Erin N Frazee
- Hospital Pharmacy Services, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
| | - Andrew D Rule
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
- Division of Epidemiology, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
| | - Sandra M Herrmann
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
| | - Kianoush B Kashani
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
- Division of Pulmonary and Critical Care Medicine, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
| | - Nelson Leung
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
| | - Abinash Virk
- Division of Infectious Diseases, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
| | - Nikolay Voskoboev
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
| | - John C Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Rochester MN 55905, USA
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Levey AS, Fan L, Eckfeldt JH, Inker LA. Cystatin C for glomerular filtration rate estimation: coming of age. Clin Chem 2014; 60:916-9. [PMID: 24871681 DOI: 10.1373/clinchem.2014.225383] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Andrew S Levey
- Division of Nephrology, Tufts Medical Center, Boston, MA;
| | - Li Fan
- Division of Nephrology, Tufts Medical Center, Boston, MA; Department of Nephrology, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - John H Eckfeldt
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN
| | - Lesley A Inker
- Division of Nephrology, Tufts Medical Center, Boston, MA
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Oh KH, Park SK, Park HC, Chin HJ, Chae DW, Choi KH, Han SH, Yoo TH, Lee K, Kim YS, Chung W, Hwang YH, Kim SW, Kim YH, Kang SW, Park BJ, Lee J, Ahn C. KNOW-CKD (KoreaN cohort study for Outcome in patients With Chronic Kidney Disease): design and methods. BMC Nephrol 2014; 15:80. [PMID: 24884708 PMCID: PMC4050398 DOI: 10.1186/1471-2369-15-80] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/07/2014] [Indexed: 11/26/2022] Open
Abstract
Background The progression and complications of chronic kidney disease should differ depending on the cause (C), glomerular filtration rate category (G), and albuminuria (A). The KNOW-CKD (KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease), which is a prospective cohort study, enrolls subjects with chronic kidney disease stages 1 to 5 (predialysis). Methods/Design Nine nephrology centers in major university hospitals throughout Korea will enroll approximately 2,450 adults with chronic kidney disease over a 5-year period from 2011 to 2015. The participating individuals will be monitored for approximately 10 years until death or until end-stage renal disease occurs. The subjects will be classified into subgroups based on the following specific causes of chronic kidney disease: glomerulonephritis, diabetic nephropathy, hypertensive nephropathy, polycystic kidney disease, and others. The eligible subjects will be evaluated at baseline for socio-demographic information, detailed personal/family history, office BP, quality of life, and health behaviors. After enrollment in the study, thorough assessments, including laboratory tests, cardiac evaluation and radiologic imaging, will be performed according to the standardized protocol. The biospecimen samples will be collected regularly. A renal event is defined by >50% decrease in estimated GFR (eGFR) from the baseline values, doubling of serum creatinine, or end-stage renal disease. The primary composite outcome consists of renal events, cardiovascular events, and death. As of September 2013, 1,470 adult chronic kidney disease subjects were enrolled in the study, including 543 subjects with glomerulonephritis, 317 with diabetic nephropathy, 294 with hypertensive nephropathy and 249 with polycystic kidney disease. Discussion As the first large-scale chronic kidney disease cohort study to be established and maintained longitudinally for up to 10 years, the KNOW-CKD will help to clarify the natural course, complication profiles, and risk factors of Asian populations with chronic kidney disease. Trial registration No. NCT01630486 at http://www.clinicaltrials.gov.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Curie Ahn
- Department of Internal Medicine, Seoul National University, 101 Daehakro, Chongno Gu, Seoul 110-744, Korea.
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Grubb A, Horio M, Hansson LO, Björk J, Nyman U, Flodin M, Larsson A, Bökenkamp A, Yasuda Y, Blufpand H, Lindström V, Zegers I, Althaus H, Blirup-Jensen S, Itoh Y, Sjöström P, Nordin G, Christensson A, Klima H, Sunde K, Hjort-Christensen P, Armbruster D, Ferrero C. Generation of a new cystatin C-based estimating equation for glomerular filtration rate by use of 7 assays standardized to the international calibrator. Clin Chem 2014; 60:974-86. [PMID: 24829272 DOI: 10.1373/clinchem.2013.220707] [Citation(s) in RCA: 215] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Many different cystatin C-based equations exist for estimating glomerular filtration rate. Major reasons for this are the previous lack of an international cystatin C calibrator and the nonequivalence of results from different cystatin C assays. METHODS Use of the recently introduced certified reference material, ERM-DA471/IFCC, and further work to achieve high agreement and equivalence of 7 commercially available cystatin C assays allowed a substantial decrease of the CV of the assays, as defined by their performance in an external quality assessment for clinical laboratory investigations. By use of 2 of these assays and a population of 4690 subjects, with large subpopulations of children and Asian and Caucasian adults, with their GFR determined by either renal or plasma inulin clearance or plasma iohexol clearance, we attempted to produce a virtually assay-independent simple cystatin C-based equation for estimation of GFR. RESULTS We developed a simple cystatin C-based equation for estimation of GFR comprising only 2 variables, cystatin C concentration and age. No terms for race and sex are required for optimal diagnostic performance. The equation, [Formula: see text] is also biologically oriented, with 1 term for the theoretical renal clearance of small molecules and 1 constant for extrarenal clearance of cystatin C. CONCLUSIONS A virtually assay-independent simple cystatin C-based and biologically oriented equation for estimation of GFR, without terms for sex and race, was produced.
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Affiliation(s)
- Anders Grubb
- Department of Clinical Chemistry, Laboratory Medicine, University Hospital, Lund, Sweden;
| | - Masaru Horio
- Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | | | - Jonas Björk
- Department of Occupational and Environmental Medicine, Lund University, Lund, Sweden
| | - Ulf Nyman
- Department of Radiology, Central Hospital, Kristianstad, University of Lund, Sweden
| | - Mats Flodin
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Anders Larsson
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Arend Bökenkamp
- Department of Pediatric Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | - Yoshinari Yasuda
- Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Hester Blufpand
- Department of Pediatric Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | - Veronica Lindström
- Department of Clinical Chemistry, Laboratory Medicine, University Hospital, Lund, Sweden
| | - Ingrid Zegers
- Institute for Reference Materials and Measurements, Joint Research Centre, European Commission, Geel, Belgium
| | - Harald Althaus
- Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany
| | - Søren Blirup-Jensen
- Department of Clinical Chemistry, Laboratory Medicine, University Hospital, Lund, Sweden
| | - Yoshi Itoh
- Department of Laboratory Medicine, EIJU, General Hospital, Tokyo, Japan
| | - Per Sjöström
- Department of Medicine, Örebro University Hospital, Örebro, Sweden
| | | | - Anders Christensson
- Department of Nephrology and Transplantation, Skåne University Hospital, Lund, Sweden
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Calibration and precision of serum creatinine and plasma cystatin C measurement: impact on the estimation of glomerular filtration rate. J Nephrol 2014; 27:467-75. [PMID: 24711159 DOI: 10.1007/s40620-014-0087-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/27/2014] [Indexed: 01/31/2023]
Abstract
Serum creatinine (SCr) is the main variable for estimating glomerular filtration rate (GFR). Due to inter-assay differences, the prevalence of chronic kidney disease (CKD) varies according to the assay used, and calibration standardization is necessary. For SCr, isotope dilution mass spectrometry (IDMS) is the gold standard. Systematic differences are observed between Jaffe and enzymatic methods. Manufacturers subtract 0.30 mg/dl from Jaffe results to match enzymatic results ('compensated Jaffe method'). The analytical performance of enzymatic methods is superior to that of Jaffe methods. In the original Modification of Diet in Renal Disease (MDRD) equation, SCr was measured by a Jaffe Beckman assay, which was later recalibrated. A limitation of this equation was an underestimation of GFR in the high range. The Chronic Kidney Disease Epidemiology (CKD-EPI) consortium proposed an equation using calibrated and IDMS traceable SCr. The gain in performance was due to improving the bias whereas the precision was comparable. The CKD-EPI equation performs better at high GFR levels (GFR >60 ml/min/1.73 m(2)). Analytical limitations have led to the recommendation to give a grade (>60 ml/min/1.73 m(2)) rather than an absolute value with the MDRD equation. By using both enzymatic and calibrated methods, this cutoff-grade could be increased to 90 ml/min/1.73 m(2) (with MDRD) and 120 ml/min/1.73 m(2) (with CKD-EPI). The superiority of the CKD-EPI equation over MDRD is analytical, but the precision gain is limited. IDMS traceable enzymatic methods have been used in the development of the Lund-Malmö (in CKD populations) and Berlin Initiative Study equations (in the elderly). The analytical errors for cystatin C are grossly comparable to issues found with SCr. Standardization is available since 2011. A reference method for cystatin C is still lacking. Equations based on standardized cystatin C or cystatin C and creatinine have been proposed. The better performance of these equations (especially the combined CKD-EPI equation) has been demonstrated.
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Levey AS, Inker LA, Coresh J. GFR estimation: from physiology to public health. Am J Kidney Dis 2014; 63:820-34. [PMID: 24485147 DOI: 10.1053/j.ajkd.2013.12.006] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/11/2013] [Indexed: 12/27/2022]
Abstract
Estimating glomerular filtration rate (GFR) is essential for clinical practice, research, and public health. Appropriate interpretation of estimated GFR (eGFR) requires understanding the principles of physiology, laboratory medicine, epidemiology, and biostatistics used in the development and validation of GFR estimating equations. Equations developed in diverse populations are less biased at higher GFRs than equations developed in chronic kidney disease (CKD) populations and are more appropriate for general use. Equations that include multiple endogenous filtration markers are more precise than equations including a single filtration marker. The CKD-EPI (CKD Epidemiology Collaboration) equations are the most accurate GFR estimating equations that have been evaluated in large diverse populations and are applicable for general clinical use. The 2009 CKD-EPI creatinine equation is more accurate in estimating GFR and prognosis than the 2006 MDRD (Modification of Diet in Renal Disease) Study equation and provides lower estimates of prevalence of decreased eGFR. It is useful as a "first test" for decreased eGFR and should replace the MDRD Study equation for routine reporting of serum creatinine-based eGFR by clinical laboratories. The 2012 CKD-EPI cystatin C equation is as accurate as the 2009 CKD-EPI creatinine equation in estimating GFR, does not require specification of race, and may be more accurate in patients with decreased muscle mass. The 2012 CKD-EPI creatinine-cystatin C equation is more accurate than the 2009 CKD-EPI creatinine and 2012 CKD-EPI cystatin C equations and is useful as a confirmatory test for decreased eGFR as determined by serum creatinine-based eGFR. Further improvement in GFR estimating equations will require development in more broadly representative populations, including diverse racial and ethnic groups, use of multiple filtration markers, and evaluation using statistical techniques to compare eGFR to "true GFR."
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Affiliation(s)
- Andrew S Levey
- William B. Schwartz Division of Nephrology, Tufts Medical Center, Department of Medicine, Tufts University School of Medicine, Boston, MA.
| | - Lesley A Inker
- William B. Schwartz Division of Nephrology, Tufts Medical Center, Department of Medicine, Tufts University School of Medicine, Boston, MA
| | - Josef Coresh
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, MD
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Fan L, Inker LA, Rossert J, Froissart M, Rossing P, Mauer M, Levey AS. Glomerular filtration rate estimation using cystatin C alone or combined with creatinine as a confirmatory test. Nephrol Dial Transplant 2014; 29:1195-203. [PMID: 24449101 DOI: 10.1093/ndt/gft509] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Glomerular filtration rate (GFR) estimating equations using the combination of creatinine and cystatin C (eGFRcr-cys) are more accurate than equations using either alone (eGFRcr or eGFRcys). New guidelines suggest measuring cystatin C as a confirmatory test when eGFRcr may be inaccurate, but do not specify demographic or clinical conditions in which eGFRcys or eGFRcr-cys are more accurate than eGFRcr nor which estimate to use in such circumstances. METHODS We compared the performance of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in 1119 subjects in the CKD-EPI cystatin C external validation dataset. Subgroups were defined by eGFRcr, age, sex, diabetes status and body mass index (BMI). The reference test was GFR measured using urinary or plasma clearance of exogenous filtration markers. Cystatin C and creatinine assays were traceable to primary reference materials. Accuracy was defined as the absolute difference in eGFR compared with mGFR. RESULTS The mean mGFR was 70 ± 41 (SD) mL/min/1.73 m(2). eGFRcys was more accurate than eGFRcr at lower BMI and less accurate at higher BMI, especially at higher levels of eGFRcr. There were small differences in accuracy in people according to the diabetes status. eGFRcr-cys was as accurate or more accurate than eGFRcr or eGFRcys in these and all other subgroups. CONCLUSIONS eGFRcr-cys, but not eGFRcys, is more accurate than eGFRcr in most subgroups we studied, suggesting preferential use of eGFRcr-cys when serum cystatin C is measured as a confirmatory test to obtain more accurate eGFR. Further studies are necessary to evaluate diagnostic strategies for using eGFRcys and eGFRcr-cys.
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Affiliation(s)
- Li Fan
- Division of Nephrology, Tufts Medical Center, Boston, MA, USA
| | - Lesley A Inker
- Division of Nephrology, Tufts Medical Center, Boston, MA, USA
| | - Jerome Rossert
- Global Clinical Development, Amgen, Thousand Oaks, CA, USA
| | - Marc Froissart
- INSERM, CESP Centre for Research in Epidemiology and Population Health, U1018, Epidemiology of Diabetes, Obesity, and Chronic Kidney Diseases Team, Villejuif 94807, France
| | | | - Michael Mauer
- Department of Pediatrics, Medical School, University of Minnesota, Minneapolis, MN, USA
| | - Andrew S Levey
- Division of Nephrology, Tufts Medical Center, Boston, MA, USA
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Factors other than the glomerular filtration rate that determine the serum beta-2-microglobulin level. PLoS One 2013; 8:e72073. [PMID: 23991042 PMCID: PMC3750024 DOI: 10.1371/journal.pone.0072073] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 07/09/2013] [Indexed: 11/22/2022] Open
Abstract
Background β2-microglobulin has been increasingly investigated as a diagnostic marker of kidney function and a prognostic marker of adverse outcomes. To date, non-renal determinants of β2-microglobulin levels have not been well described. Non-renal determinants are important for the interpretation and appraisal of the diagnostic and prognostic value of any endogenous kidney function marker. Methods This cross-sectional analysis was performed within the framework of the www.seniorlabor.ch study, which includes subjectively healthy individuals aged ≥60 years. Factors known or suspected to have a non-renal association with kidney function markers were investigated for a non-renal association with serum β2-microglobulin. As a marker of kidney function, the Berlin Initiative Study equation 2 for the estimation of the estimated glomerular filtration rate (eGFRBIS2) in the elderly was employed. Results A total of 1302 participants (714 females and 588 males) were enrolled in the study. The use of a multivariate regression model adjusting for age, gender and kidney function (eGFRBIS2) revealed age, male gender, and C-reactive protein level to be positively associated with β2-microglobulin levels. In addition, there was an inverse non-renal relationship between systolic blood pressure, total cholesterol and current smoking status. No association with markers of diabetes mellitus, body stature, nutritional risk, thyroid function or calcium and phosphate levels was observed. Conclusions Serum β2-microglobulin levels in elderly subjects are related to several non-renal factors. These non-renal factors are not congruent to those known from other markers (i.e. cystatin C and creatinine) and remind of classical cardiovascular risk factors.
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Terpos E, Christoulas D, Kastritis E, Katodritou E, Pouli A, Michalis E, Papassotiriou I, Dimopoulos MA. The Chronic Kidney Disease Epidemiology Collaboration cystatin C (CKD-EPI-CysC) equation has an independent prognostic value for overall survival in newly diagnosed patients with symptomatic multiple myeloma; is it time to change from MDRD to CKD-EPI-CysC equations? Eur J Haematol 2013; 91:347-55. [PMID: 23829647 DOI: 10.1111/ejh.12164] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2013] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The estimation of glomerular filtration rate (eGFR) in multiple myeloma (MM) is based on equations that use serum creatinine (sCr), such as the Modification of Diet in Renal Disease (MDRD) equation. However, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) group has suggested that eGFR based on both sCr and cystatin C (CKD-EPI-sCr-CysC) is more accurate than other formulae for the estimation of kidney dysfunction. The aim of this study was to prospectively evaluate, for the first time in the literature, the CKD-EPI-sCR-CysC formula in newly diagnosed patients with symptomatic MM. METHODS We studied 220 newly diagnosed, previously untreated, patients with symptomatic myeloma and calculated eGFR using the MDRD, the CKD-EPI-sCR, the CKD-EPI-CysC, and the CKD-EPI-sCr-CysC equations. RESULTS CKD-EPI-sCr-CysC equation detected more myeloma patients with stage 3-5 renal impairment than the MDRD, CKD-EPI, or CKD-EPI-CysC equations: 45% vs. 39.5%, 42.2%, and 43.1%, respectively (P < 0.01). This was also observed in the elderly patients (>70 yrs), while in patients ≤70 yrs, the CKD-EPI-CysC equation managed to identify higher number of patients with stage 3-5 renal impairment (RI) than the other equations. Furthermore, 63 (28.6%) patients with eGFR values by the MDRD formula were reclassified to higher CKD stages according to CKD-EPI-CysC equation. The median overall survival for all patients was 52 months. In the multivariate analysis, that included International Staging System stage, lactate dehydrogenase (LDH) ≥300 U/L and eGFR for each different equation (as a continuous variable), only eGFR that included CysC, but not sCr had independent prognostic value (P = 0.013) along with high LDH (P = 0.029). CONCLUSIONS Our results suggest that equations based on CysC reveal higher number of MM patients with RI compared with equations based only in sCr. Furthermore, the CKD-EPI-CysC formula independently predicted for survival. Based on these data, we suggest that CKD-EPI equations based on CysC should substitute MDRD, as it has been suggested for patients with several other renal disorders.
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Affiliation(s)
- Evangelos Terpos
- Department of Clinical Therapeutics, National and Kapodistrian University of Athens, Medical School, Athens, Greece
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Bansal N, Vittinghoff E, Peralta CA, Shlipak MG, Grubbs V, Jacobs DR, Siscovick D, Steffes M, Carr JJ, Bibbins-Domingo K. Estimated kidney function based on serum cystatin C and risk of subsequent coronary artery calcium in young and middle-aged adults with preserved kidney function: results from the CARDIA study. Am J Epidemiol 2013; 178:410-7. [PMID: 23813702 DOI: 10.1093/aje/kws581] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Whether kidney dysfunction is associated with coronary artery calcium (CAC) in young and middle-aged adults who have a cystatin C-derived estimated glomerular filtration rate (eGFRcys) greater than 60 mL/min/1.73 m(2) is unknown. In the Coronary Artery Risk Development in Young Adults (CARDIA) cohort (recruited in 1985 and 1986 in Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; and Oakland, California), we examined 1) the association of eGFRcys at years 10 and 15 and detectable CAC over the subsequent 5 years and 2) the association of change in eGFRcys and subsequent CAC, comparing those with stable eGFRcys to those whose eGFRcys increased (>3% annually over 5 years), declined moderately (3%-5%), or declined rapidly (>5%). Generalized estimating equation Poisson models were used, with adjustment for age, sex, race, educational level, income, family history of coronary artery disease, diabetes, body mass index, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and tobacco use. Among 3,070 participants (mean age 35.6 (standard deviation, 4.1) years and mean eGFRcys 106.7 (standard deviation, 18.5) mL/min/1.73 m(2)), 529 had detectable CAC. Baseline eGFRcys was not associated with CAC. Moderate eGFRcys decline was associated with a 33% greater relative risk of subsequent CAC (95% confidence interval: 5, 68; P = 0.02), whereas rapid decline was associated with a 51% higher relative risk (95% confidence interval: 10, 208; P = 0.01) in adjusted models. In conclusion, among young and middle-aged adults with eGFRcys greater than 60 mL/min/1.73 m(2), annual decline in eGFRcys is an independent risk factor for subsequent CAC.
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Affiliation(s)
- Nisha Bansal
- Division of Nephrology, University of California, San Francisco, 521 Parnassus Avenue, Box 0532, San Francisco, CA 94143, USA.
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Performance of creatinine and cystatin C GFR estimating equations in an HIV-positive population on antiretrovirals. J Acquir Immune Defic Syndr 2013; 61:302-9. [PMID: 22842844 DOI: 10.1097/qai.0b013e31826a6c4f] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE To evaluate the performance of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine, cystatin C, and creatinine-cystatin C estimating equations in HIV-positive patients. METHODS We evaluated the performance of the Modification of Diet in Renal Disease (MDRD) Study and CKD-EPI creatinine 2009, CKD-EPI cystatin C 2012, and CKD-EPI creatinine-cystatin C 2012 glomerular filtration rate (GFR) estimating equations compared with GFR measured using plasma clearance of iohexol in 200 HIV-positive patients on stable antiretroviral therapy. Creatinine and cystatin C assays were standardized to certified reference materials. RESULTS Of the 200 participants, median (IQR) CD4 count was 536 (421) and 61% had an undetectable HIV viral load. Mean (SD) measured GFR (mGFR) was 87 (26) mL/min per 1.73 m. All CKD-EPI equations performed better than the MDRD Study equation. All 3 CKD-EPI equations had similar bias and precision. The cystatin C equation was not more accurate than the creatinine equation. The creatinine-cystatin C equation was significantly more accurate than the cystatin C equation, and there was a trend toward greater accuracy than the creatinine equation. Accuracy was equal or better in most subgroups with the combined equation compared to either alone. CONCLUSIONS The CKD-EPI cystatin C equation does not seem to be more accurate than the CKD-EPI creatinine equation in patients who are HIV-positive, supporting the use of the CKD-EPI creatinine equation for routine clinical care for use in North American populations with HIV. The use of both filtration markers together as a confirmatory test for decreased estimated GFR based on creatinine in individuals who are HIV-positive requires further study.
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Harman G, Akbari A, Hiremath S, White CA, Ramsay T, Kokolo MB, Craig J, Knoll GA. Accuracy of cystatin C-based estimates of glomerular filtration rate in kidney transplant recipients: a systematic review. Nephrol Dial Transplant 2012; 28:741-57. [PMID: 23275574 DOI: 10.1093/ndt/gfs498] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND As with creatinine, cystatin C can be incorporated into a formula to estimate the glomerular filtration rate (GFR). The overall performance of cystatin C-based equations in kidney transplantation is unclear with conflicting results between studies. METHODS Systematic review of adult kidney transplant recipients. Studies that reported mean bias (mean difference between the measured and estimated GFRs) or accuracy of the cystatin C-based GFR estimation equation (e.g. percentage of estimates within 30% of the measured GFR) against the measured GFR using renal or plasma clearance of contrast agents, radioisotopes or inulin were included. RESULTS The search identified 10 studies that examined 14 different cystatin C-based estimating equations (n = 5 equations evaluated in more than one study). The Le Bricon equation had the best performance with a bias that ranged from -6.4 to +2.8 mL/min/1.73 m(2); 85% (95% CI, 82-88) of estimates were within 30% of the measured GFR. For the other equations, 66-82% of estimates were within 30% of the measured GFR. For the modification of diet in renal disease (MDRD) equation, 68% (95% CI, 65-72) of estimates were within 30% of the measured GFR. CONCLUSIONS The cystatin C-based Le Bricon equation was the most accurate, and most of the cystatin C-based equations showed improvements in 30% and 50% accuracy compared with the creatinine-based MDRD equation. Cystatin C-based equations may offer an advantage over the MDRD equation in kidney transplant recipients. Estimating equations re-expressed with standardized cystatin C have been developed and their accuracy needs to be tested in the kidney transplant population.
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Affiliation(s)
- Gavin Harman
- Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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Nerpin E, Helmersson-Karlqvist J, Risérus U, Sundström J, Larsson A, Jobs E, Basu S, Ingelsson E, Arnlöv J. Inflammation, oxidative stress, glomerular filtration rate, and albuminuria in elderly men: a cross-sectional study. BMC Res Notes 2012; 5:537. [PMID: 23016573 PMCID: PMC3527356 DOI: 10.1186/1756-0500-5-537] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 09/22/2012] [Indexed: 01/02/2023] Open
Abstract
Background The role of inflammation and oxidative stress in mild renal impairment in the elderly is not well studied. Accordingly, we aimed at investigating the associations between estimated glomerular filtration rate (eGFR), albumin/creatinine ratio (ACR), and markers of different inflammatory pathways and oxidative stress in a community based cohort of elderly men. Findings Cystatin C-based GFR, ACR, and biomarkers of cytokine-mediated inflammation (interleukin-6, high-sensitivity C-reactive protein[CRP], serum amyloid A[SAA]), cyclooxygenase-mediated inflammation (urinary prostaglandin F2α [PGF2α]), and oxidative stress (urinary F2 isoprostanes) were assessed in the Uppsala Longitudinal Study of Adult Men(n = 647, mean age 77 years). Results In linear regression models adjusting for age, BMI, smoking, blood pressure, LDL-cholesterol, HDL-cholesterol, triglycerides, and treatment with statins, ACE-inhibitors, ASA, and anti-inflammatory agents, eGFR was inversely associated with CRP, interleukin-6, and SAA (β-coefficient −0.13 to −0.19, p < 0.001 for all), and positively associated with urinary F2-isoprostanes (β-coefficient 0.09, p = 0.02). In line with this, ACR was positively associated with CRP, interleukin-6, and SAA (β- coefficient 0.09-0.12, p < 0.02 for all), and negatively associated with urinary F2-isoprostanes (β-coefficient −0.12, p = 0.002). The associations were similar but with lower regression coefficients in a sub-sample with normal eGFR (>60 ml/min/1.73 m2, n = 514), with the exception that F2-isoprostane and SAA were no longer associated with eGFR. Conclusion Our data indicate that cytokine-mediated inflammation is involved in the early stages of impaired kidney function in the elderly, but that cyclooxygenase-mediated inflammation does not play a role at this stage. The unexpected association between higher eGFR/lower albuminuria and increased F2-isoprostanes in urine merits further studies.
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Affiliation(s)
- Elisabet Nerpin
- Department of Public Health and Caring Sciences/Geriatrics, Uppsala University, SE- 751 85, Uppsala, Sweden.
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Simple cystatin C formula for estimation of glomerular filtration rate in overweight patients with diabetes mellitus type 2 and chronic kidney disease. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:179849. [PMID: 23008697 PMCID: PMC3447360 DOI: 10.1155/2012/179849] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 06/28/2012] [Accepted: 07/12/2012] [Indexed: 02/07/2023]
Abstract
In clinical practice the glomerular filtration rate (GFR) is estimated from serum creatinine-based equations like the Cockcroft-Gault formula (C&G) and Modification of Diet in Renal Disease formula (MDRD). Recently, serum cystatin C-based equations, the newer creatinine formula (The Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI)), and equation that use both serum creatinine and cystatin C (CKD-EPI creatinine & cystatin formula) were proposed as new GFR markers. Present study compares serum creatinine-based equations, combined (including both serum creatinine and cystatin C) equation, and serum simple cystatin C formula (100/serum cystatin C) against 51CrEDTA clearance in 113 adult overweight Caucasians with diabetes mellitus type 2 (DM2) and chronic kidney disease (CKD). The results of present study demonstrated that the simple cystatin C formula could be a useful tool for the evaluation of renal function in overweight patients with DM2 and impaired kidney function in daily clinical practice in hospital and especially in outpatients. Despite the advantages of the simple cystatin C formula, cystatin C-based equations cannot completely replace the “gold standard” for estimation of the GFR in a population of DM2 patients with CKD, but may contribute to a more accurate selection of patients requiring such invasive and costly procedures.
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Inker LA, Schmid CH, Tighiouart H, Eckfeldt JH, Feldman HI, Greene T, Kusek JW, Manzi J, Van Lente F, Zhang YL, Coresh J, Levey AS. Estimating glomerular filtration rate from serum creatinine and cystatin C. N Engl J Med 2012; 367:20-9. [PMID: 22762315 PMCID: PMC4398023 DOI: 10.1056/nejmoa1114248] [Citation(s) in RCA: 2805] [Impact Index Per Article: 233.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Estimates of glomerular filtration rate (GFR) that are based on serum creatinine are routinely used; however, they are imprecise, potentially leading to the overdiagnosis of chronic kidney disease. Cystatin C is an alternative filtration marker for estimating GFR. METHODS Using cross-sectional analyses, we developed estimating equations based on cystatin C alone and in combination with creatinine in diverse populations totaling 5352 participants from 13 studies. These equations were then validated in 1119 participants from 5 different studies in which GFR had been measured. Cystatin and creatinine assays were traceable to primary reference materials. RESULTS Mean measured GFRs were 68 and 70 ml per minute per 1.73 m(2) of body-surface area in the development and validation data sets, respectively. In the validation data set, the creatinine-cystatin C equation performed better than equations that used creatinine or cystatin C alone. Bias was similar among the three equations, with a median difference between measured and estimated GFR of 3.9 ml per minute per 1.73 m(2) with the combined equation, as compared with 3.7 and 3.4 ml per minute per 1.73 m(2) with the creatinine equation and the cystatin C equation (P=0.07 and P=0.05), respectively. Precision was improved with the combined equation (interquartile range of the difference, 13.4 vs. 15.4 and 16.4 ml per minute per 1.73 m(2), respectively [P=0.001 and P<0.001]), and the results were more accurate (percentage of estimates that were >30% of measured GFR, 8.5 vs. 12.8 and 14.1, respectively [P<0.001 for both comparisons]). In participants whose estimated GFR based on creatinine was 45 to 74 ml per minute per 1.73 m(2), the combined equation improved the classification of measured GFR as either less than 60 ml per minute per 1.73 m(2) or greater than or equal to 60 ml per minute per 1.73 m(2) (net reclassification index, 19.4% [P<0.001]) and correctly reclassified 16.9% of those with an estimated GFR of 45 to 59 ml per minute per 1.73 m(2) as having a GFR of 60 ml or higher per minute per 1.73 m(2). CONCLUSIONS The combined creatinine-cystatin C equation performed better than equations based on either of these markers alone and may be useful as a confirmatory test for chronic kidney disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases.).
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Affiliation(s)
- Lesley A Inker
- Division of Nephrology, Tufts Medical Center, 800 Washington St., Box 391, Boston, MA 02111, USA.
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Anderson AH, Yang W, Hsu CY, Joffe MM, Leonard MB, Xie D, Chen J, Greene T, Jaar BG, Kao P, Kusek JW, Landis JR, Lash JP, Townsend RR, Weir MR, Feldman HI. Estimating GFR among participants in the Chronic Renal Insufficiency Cohort (CRIC) Study. Am J Kidney Dis 2012; 60:250-61. [PMID: 22658574 DOI: 10.1053/j.ajkd.2012.04.012] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 04/12/2012] [Indexed: 01/02/2023]
Abstract
BACKGROUND Glomerular filtration rate (GFR) is considered the best measure of kidney function, but repeated assessment is not feasible in most research studies. STUDY DESIGN Cross-sectional study of 1,433 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study (ie, the GFR subcohort) to derive an internal GFR estimating equation using a split-sample approach. SETTING & PARTICIPANTS Adults from 7 US metropolitan areas with mild to moderate chronic kidney disease; 48% had diabetes and 37% were black. INDEX TEST CRIC GFR estimating equation. REFERENCE TEST OR OUTCOME Urinary (125)I-iothalamate clearance testing (measured GFR [mGFR]). OTHER MEASUREMENTS Laboratory measures, including serum creatinine and cystatin C, and anthropometrics. RESULTS In the validation data set, the model that included serum creatinine level, serum cystatin C level, age, sex, and race was the most parsimonious and similarly predictive of mGFR compared with a model additionally including bioelectrical impedance analysis phase angle, CRIC clinical center, and 24-hour urinary creatinine excretion. Specifically, root mean square errors for the separate models were 0.207 versus 0.202, respectively. Performance of the CRIC GFR estimating equation was most accurate for the subgroups of younger participants, men, nonblacks, non-Hispanics, those without diabetes, those with body mass index <30 kg/m(2), those with higher 24-hour urine creatinine excretion, those with lower high-sensitivity C-reactive protein levels, and those with higher mGFRs. LIMITATIONS Urinary clearance of (125)I-iothalamate is an imperfect measure of true GFR; cystatin C level is not standardized to certified reference material; lack of external validation; small sample sizes limit analyses of subgroup-specific predictors. CONCLUSIONS The CRIC GFR estimating equation predicts mGFR accurately in the CRIC cohort using serum creatinine and cystatin C levels, age, sex, and race. Its performance was best in younger and healthier participants.
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Affiliation(s)
- Amanda Hyre Anderson
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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How to Assess Kidney Function: Overview. Clin Ther 2012. [DOI: 10.1016/j.clinthera.2012.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Inker LA, Eckfeldt J, Levey AS, Leiendecker-Foster C, Rynders G, Manzi J, Waheed S, Coresh J. Expressing the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) cystatin C equations for estimating GFR with standardized serum cystatin C values. Am J Kidney Dis 2011; 58:682-4. [PMID: 21855190 DOI: 10.1053/j.ajkd.2011.05.019] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/19/2011] [Indexed: 11/11/2022]
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White CA, Rule AD, Collier CP, Akbari A, Lieske JC, Lepage N, Doucette S, Knoll GA. The impact of interlaboratory differences in cystatin C assay measurement on glomerular filtration rate estimation. Clin J Am Soc Nephrol 2011; 6:2150-6. [PMID: 21799146 DOI: 10.2215/cjn.00130111] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Cystatin C (CysC) is a promising marker of GFR. Several equations have been derived to estimate GFR from its serum concentration. Heterogeneity in the performance of these equations exists in validation studies even when the same CysC assay from the same manufacturer is utilized. This study was designed to examine the differences in CysC and GFR estimation (eGFR) using Siemens' nephelometric immunoassay and the Mayo Clinic equation. The ability of the eGFRs to predict measured GFR was also examined. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Ninety-seven split samples were sent to laboratories at Children's Hospital of Eastern Ontario (CHEO) in Ottawa, Canada, and at the Mayo Clinic in Rochester, Minnesota. RESULTS The mean CHEO CysC was 0.17 mg/L (10%) lower than the mean Mayo Clinic CysC. Using the Mayo Clinic equation, the mean eGFR difference was 7.2 ml/min per 1.73 m(2) (15%). Approximately 36% of the results agreed within 10%, while 13% were discordant by greater than 30%. Larger absolute differences in mean eGFR between the two laboratories were found in the subgroup with CysC less than 1.41 mg/L as compared with the subgroup greater than 1.41 mg/L (9.5 versus 5.0 ml/min per 1.73 m(2)). Correction of CHEO values to the Mayo Clinic did not improve GFR estimation. CONCLUSIONS Significant differences in CysC measurement exist between laboratories using the same assay by the same manufacturer and these lead to clinically relevant differences in GFR estimation. This interlaboratory variability needs to be recognized when interpreting and comparing CysC and eGFR results.
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Affiliation(s)
- Christine A White
- Division of Nephrology, Department of Medicine, Queen’s University, Kingston, Ontario, Canada.
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Delanghe JR, Cobbaert C, Harmoinen A, Jansen R, Laitinen P, Panteghini M. Focusing on the clinical impact of standardization of creatinine measurements: a report by the EFCC Working Group on Creatinine Standardization. Clin Chem Lab Med 2011; 49:977-82. [PMID: 21428858 DOI: 10.1515/cclm.2011.167] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The recent campaign for standardization of creatinine measurements has been promoted to allow the widespread use of formulas for estimating the glomerular filtration rate (GFR). However, studies on trueness verification and measurement interferences still show disappointing interassay variation of serum creatinine results. Creatinine recalibration has major clinical consequences. In particular, in pediatrics where reference ranges for serum and plasma creatinine are low, calculation of the GFR is problematic when based on alkaline picrate methods because of method non-specificity and the lack of appropriate GFR estimating formulas. Therefore, enzymatic creatinine assays are preferred. In the near future, cystatin C might offer an interesting alternative for GFR estimation. For the calculation of drug doses, the Modification of Diet in Renal Disease study formula generally offers reliable data. However, attention has to be paid to the elderly. Also, the calculation of the Model for End-Stage Liver Disease score, which is used to prioritize patients for liver transplantation, may significantly be influenced by recalibration of creatinine assays. Creatinine restandardization may also affect the current guidelines for referral of chronic kidney disease patients to nephrologists.
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Affiliation(s)
- Joris R Delanghe
- Department of Clinical Chemistry, University Hospital, Gent, Belgium.
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Shlipak MG, Weekley CC, Li Y, Hansson LO, Larsson A, Whooley M. Comparison of cardiovascular prognosis by 3 serum cystatin C methods in the Heart and Soul Study. Clin Chem 2011; 57:737-45. [PMID: 21310869 DOI: 10.1373/clinchem.2010.158915] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Cystatin C is a promising new biomarker to determine the estimated glomerular filtration. However, the Siemens' cystatin C assay (Siemens), used in many longitudinal studies, has had limited clinical applicability because it requires a specific, dedicated instrument. Other companies, including Gentian and Roche, have developed cystatin C assays that can be used with most routine clinical chemistry analyzers. METHODS We compared the agreement of Gentian and Roche with Siemens assays in 948 participants at the baseline visit of the Heart and Soul Study, a cohort of participants with established coronary artery disease who were followed for an average of 8 years. We then compared associations of all 3 cystatin C measures and eGFR-Modification of Diet in Renal Disease (MDRD) with clinical outcomes. RESULTS The Gentian assay had higher correlation with Siemens (r = 0.96) than did Roche (r = 0.93, P < 0.001). After cross-tabulating quartiles of each cystatin C measure, agreements (κ statistic) were higher for Siemens and Gentian (0.73, 95% CI 0.72-0.75) than for Roche and Siemens (0.64, 0.63-0.66) or for Roche and Gentian (0.69, 0.65-0.71). These differences in agreement had minimal impact on associations with clinical outcomes; the hazard ratios (HRs) for mortality comparing the high vs low quartiles were 3.2 (95% CI 2.1-4.8) for Siemens, 3.1 (CI 2.1-4.7) for Gentian, 3.1 (CI 2.1-4.7) for Roche, and 1.6 (CI 1.1-2.3) for eGFR-MDRD, after multivariate adjustment. CONCLUSIONS In summary, agreement with the Siemens' assay was modestly higher for the Gentian compared with the Roche assay, although all 3 methods for cystatin C measurement had similar utility as predictors of clinical outcomes.
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Wetmore JB, Palsson R, Belmont JM, Sigurdsson G, Franzson L, Indridason OS. Discrepancies between creatinine- and cystatin C-based equations: implications for identification of chronic kidney disease in the general population. ACTA ACUST UNITED AC 2010; 44:242-50. [PMID: 20367222 DOI: 10.3109/00365591003709450] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Early detection and treatment of chronic kidney disease (CKD) is important for slowing the progression of the disease and decreasing the associated risk of cardiovascular disease. This study examined how two creatinine-based and two cystatin C-based equations for calculating estimated glomerular filtration rate (eGFR) perform relative to each other in identifying CKD in a large cohort of community-dwelling individuals. MATERIAL AND METHODS A total of 1630 adults were recruited from the Reykjavik area. Each subject's eGFR was calculated using the Modification of Diet in Renal Disease (MDRD) Study and Cockroft-Gault equations, and two cystatin C-based equations. The prevalence of decreased eGFR obtained by the four equations was compared and the relative performance of the equations examined. RESULTS The MDRD equation labelled significantly fewer individuals as having CKD (5.3%) relative to the other equations (12.8-19.7%). Agreement between equations was limited, with up to one-third of subjects diagnosed as having CKD by the MDRD equation being classified as normal by other equations. Correlations between creatinine- and cystatin C-based equations varied with age, gender and diuretic use. CONCLUSIONS The MDRD equation results in lower population-wide estimates of CKD relative to the other equations tested. An understanding of the performance of these equations is critical when they are used for estimating the prevalence of CKD in a population-wide setting or for diagnosing the disorder in clinical practice.
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Affiliation(s)
- James B Wetmore
- Division of Nephrology and Hypertension, Department of Medicine, University of Kansas School of Medicine, Kansas City, Kansas, USA
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Bargnoux AS, Cavalier E, Cristol JP, Simon N, Dupuy AM, Garrigue V, Badiou S, Delanaye P, Mourad G. Cystatin C is a reliable marker for estimation of glomerular filtration rate in renal transplantation: validation of a new turbidimetric assay using monospecific sheep antibodies. Clin Chem Lab Med 2010; 49:265-70. [PMID: 21110777 DOI: 10.1515/cclm.2011.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The potential use of cystatin C was recently assessed in kidney transplantation. A new particle-enhanced turbidimetric immunoassay (PETIA) that uses sheep antibodies (Binding Site human cystatin C immunoassay) has been developed. Analytical performance of this new assay was evaluated. Clinical relevance was determined by comparison with a reference method in a cohort of kidney transplant patients. METHODS First, the analytical performance of the Binding Site cystatin C kit was tested on SPA(PLUS)® and Hitachi® analyzers. Second, a comparison study was performed using SPA(PLUS)® analyzer against two other cystatin C methods (the Siemens-PENIA method on BNII® and the Dako-PETIA application on Olympus AU640®). Third, the glomerular filtration rate (GFR) was estimated using several predictive cystatin C- and creatinine-based equations and compared to GFR measured by an isotopic method (⁹⁹(m)Tc-DTPA). These predictive algorithms were analyzed with respect to bias, precision and accuracy. RESULTS Total intra-assay and inter-assay coefficients of variation were below 5%. Values obtained with the SPA(PLUS)® correlated with the Siemens-PENIA and the Dako-PETIA methods. The creatinine and cystatin C-based equation allowed reliable assessment of GFR in our population of renal transplantation. CONCLUSIONS The use of algorithms based on cystatin C and creatinine could provide a reliable estimate of GFR in kidney transplantation.
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