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Horace RW, Roberts M, Shireman TI, Merhi B, Jacques P, Bostom AG, Liu S, Eaton CB. Remnant cholesterol is prospectively associated with CVD events and all-cause mortality in kidney transplant recipients: the FAVORIT study. Nephrol Dial Transplant 2021; 37:382-389. [PMID: 33760035 DOI: 10.1093/ndt/gfab068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The cholesterol content of circulating triglyceride-rich lipoproteins is characterized as remnant cholesterol, although little is known about its role in the development of CVD outcomes, all-cause mortality, or transplant failure in kidney transplant recipients. Our primary aim was to investigate the prospective association of remnant cholesterol and the risk of CVD events in renal transplant recipients with secondary aims evaluating remnant cholesterol and renal graft failure and all-cause mortality among participants in the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) trial. METHODS Among 4,110 enrolled participants, 98 were excluded for missing baseline remnant cholesterol levels and covariates. Non fasting remnant cholesterol levels were calculated based upon lipid profiles in 3,812 FAVORIT trial participants at randomization. Wilcoxon-type test for trend were used to compare baseline characteristics across remnant cholesterol quartiles. Cox proportional hazards regression was used to evaluate the association of baseline remnant cholesterol levels with time to primary and secondary study outcomes. RESULTS During a median follow-up of 4.0 years, we documented 548 CVD incident events, 343 transplant failures, 452 All-Cause deaths. When comparing highest quartile 4 to quartile 1, proportional hazards modeling revealed a significant increase in CVD risk (HR, 1.32; 95% CI, 1.04-1.67) and all-cause mortality risk (HR, 1.34; 95% CI, 1.01-1.69). A non-significant increase in transplant failure was seen as well (HR, 1.20; 95% CI, 0.87-1.64). CONCLUSION Remnant cholesterol is associated with CVD and all-cause mortality in long-term kidney transplant recipients KTRs. A randomized controlled clinical trial in KTRs that assesses the potential impact of remnant cholesterol-lowering therapy on these outcomes may be warranted.
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Affiliation(s)
- Reuben William Horace
- Brown University School of Public Health, Department of Epidemiology, USA.,Center for Primary Care, Prevention, Brown University, Providence, RI, USA
| | - Mary Roberts
- Center for Primary Care, Prevention, Brown University, Providence, RI, USA
| | - Theresa I Shireman
- Brown University School of Public Health: Center for Gerontology and Healthcare Research, Brown University, Providence, RI, USA
| | - Basma Merhi
- Division of Hypertension and Kidney Diseases, Department of Medicine, Rhode Island Hospital, USA
| | - Paul Jacques
- Nutritional Epidemiology Program, USDA Human Nutrition Research Center on Aging, USA
| | - Andrew G Bostom
- Division of Hypertension and Kidney Diseases, Department of Medicine, USA
| | - Simin Liu
- Departments of Epidemiology and Medicine and Center for Global Cardiometabolic Health, USA
| | - Charles B Eaton
- Center for Primary Care, Prevention, Brown University, Providence, RI, USA
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2
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Kang AW, Bostom AG, Kim H, Eaton CB, Gohh R, Kusek JW, Pfeffer MA, Risica PM, Garber CE. Physical activity and risk of cardiovascular events and all-cause mortality among kidney transplant recipients. Nephrol Dial Transplant 2020; 35:1436-1443. [PMID: 32437569 DOI: 10.1093/ndt/gfaa038] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Insufficient physical activity (PA) may increase the risk of all-cause mortality and cardiovascular disease (CVD) morbidity and mortality among kidney transplant recipients (KTRs), but limited research is available. We examine the relationship between PA and the development of CVD events, CVD death and all-cause mortality among KTRs. METHODS A total of 3050 KTRs enrolled in an international homocysteine-lowering randomized controlled trial were examined (38% female; mean age 51.8 ± 9.4 years; 75% white; 20% with prevalent CVD). PA was measured at baseline using a modified Yale Physical Activity Survey, divided into tertiles (T1, T2 and T3) from lowest to highest PA. Kaplan-Meier survival curves were used to graph the risk of events; Cox proportional hazards regression models examined the association of baseline PA levels with CVD events (e.g. stroke, myocardial infarction), CVD mortality and all-cause mortality over time. RESULTS Participants were followed up to 2500 days (mean 3.7 ± 1.6 years). The cohort experienced 426 CVD events and 357 deaths. Fully adjusted models revealed that, compared to the lowest tertile of PA, the highest tertile experienced a significantly lower risk of CVD events {hazard ratio [HR] 0.76 [95% confidence interval (CI) 0.59-0.98]}, CVD mortality [HR 0.58 (95% CI 0.35-0.96)] and all-cause mortality [HR 0.76 (95% CI 0.59-0.98)]. Results were similar in unadjusted models. CONCLUSIONS PA was associated with a reduced risk of CVD events and all-cause mortality among KTRs. These observed associations in a large, international sample, even when controlling for traditional CVD risk factors, indicate the potential importance of PA in reducing CVD and death among KTRs.
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Affiliation(s)
- Augustine W Kang
- Center for Health Equity Research, Brown University School of Public Health, Providence, RI, USA.,Department of Behavioral and Social Sciences, Brown University School of Public Health, Providence, RI, USA
| | - Andrew G Bostom
- Department of Family Medicine, Warren Alpert Medical School of Brown University, Providence, RI, USA.,Center for Primary Care and Prevention, Kent Hospital, Warwick, RI, USA
| | - Hongseok Kim
- Department of Epidemiology, Brown University School of Public Health, Providence, RI, USA
| | - Charles B Eaton
- Department of Family Medicine, Warren Alpert Medical School of Brown University, Providence, RI, USA.,Center for Primary Care and Prevention, Kent Hospital, Warwick, RI, USA.,Department of Epidemiology, Brown University School of Public Health, Providence, RI, USA
| | - Reginald Gohh
- Division of Nephrology, Rhode Island Hospital, Providence, RI, USA
| | - John W Kusek
- Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, Philadelphia, PA, USA
| | - Marc A Pfeffer
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Patricia M Risica
- Center for Health Equity Research, Brown University School of Public Health, Providence, RI, USA.,Department of Behavioral and Social Sciences, Brown University School of Public Health, Providence, RI, USA.,Department of Epidemiology, Brown University School of Public Health, Providence, RI, USA
| | - Carol E Garber
- Teachers' College, Columbia University, New York, NY, USA
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Shemin D, Bostom AG, Lambert C, Hill C, Kitsen J, Kliger AS. Residual Renal Function in a Large Cohort of Peritoneal Dialysis Patients: Change over Time, Impact on Mortality and Nutrition. Perit Dial Int 2020. [DOI: 10.1177/089686080002000411] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
ObjectiveResidual renal function contributes importantly to total solute clearance in peritoneal dialysis (PD) patients. This study was designed to examine the progression of residual renal function over time and its impact on nutrition and mortality in PD patients in the six New England states (ME, NH, VT, CT, MA, RI) comprising End Stage Renal Disease (ESRD) Network 1.DesignAs part of the ESRD Clinical Indicators Project, data on 990 PD patients in Network 1 were abstracted from data supplied by dialysis units in the fourth quarter of 1997. This included demographic information; dose of PD in L/day; weekly renal, dialysis, and total Kt/V urea; weekly renal, dialysis, and total creatinine clearance (CCr); serum albumin level; and mortality and transplantation information. Data collection was repeated in the second and fourth quarters of 1998 and in the second quarter of 1999.Patients990 PD patients in Network 1.Outcome MeasuresThe change in total and renal solute clearances over time, the relationship between renal clearance and mortality, and the relationship between renal clearance and nutritional status, as represented by serum albumin.ResultsOver the 2-year period, mean weekly renal Kt/V urea and weekly renal CCr dropped significantly. To examine the effect of residual renal function on mortality, patients were divided into high and low (above and below the median) weekly renal Kt/V urea and weekly renal CCr groups. Patients above the median levels of both weekly renal Kt/V urea and weekly renal CCr had a significantly decreased risk of dying during the observation period, after controlling for age, gender, serum albumin level, and diabetic status [OR for high vs low renal Kt/V urea 0.54 (CI 0.34 – 0.84), OR for high vs low renal CCr 0.61 (CI 0.40 – 0.94)]. The mean weekly renal Kt/V urea was significantly and directly correlated with the mean serum albumin level by Spearman rank correlation ( R = 0.133, p < 0.001), as was the mean weekly renal CCr ( R = 0.115, p < 0.001).ConclusionsResidual renal function is an important contributor to total solute clearance in PD patients. Even at low levels it is linked to decreased mortality and better nutritional status.
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Affiliation(s)
- Douglas Shemin
- Division of Renal Diseases, Rhode Island/Brown University School of Medicine, Providence, Rhode Island
- End Stage Renal Disease Network of New England New Haven, Connecticut, U.S.A
| | - Andrew G. Bostom
- Division of Renal Diseases, Rhode Island/Brown University School of Medicine, Providence, Rhode Island
| | - Cynthia Lambert
- End Stage Renal Disease Network of New England New Haven, Connecticut, U.S.A
| | - Connie Hill
- End Stage Renal Disease Network of New England New Haven, Connecticut, U.S.A
| | - Jenny Kitsen
- End Stage Renal Disease Network of New England New Haven, Connecticut, U.S.A
| | - Alan S. Kliger
- End Stage Renal Disease Network of New England New Haven, Connecticut, U.S.A
- Yale University School of Medicine, New Haven, Connecticut, U.S.A
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Abstract
PURPOSE Research examining the relationship between physical activity (PA) and cardiovascular disease (CVD) risk factors among kidney transplant recipients (KTR) is limited. Accordingly, we sought to 1) describe the levels of PA in KTR and 2) analyze the associations between PA levels and CVD risk factors in KTR. METHODS Baseline data from KTR participants in a large multiethnic, multicenter trial (the Folic Acid for Vascular Outcome Reduction in Transplantation) were examined. PA was categorized in tertiles (low, moderate, and high) derived from a modified PA summary score from the Yale Physical Activity Survey. CVD risk factors were examined across levels of PA by ANOVA, Kruskal-Wallis rank test, and hierarchical multiple regression. RESULTS The 4034 participants were 37% female (mean ± SD = 51.9 ± 9.4 yr of age, 75% White, 97% with stage 2T-4T chronic kidney disease, and 20% with prevalent CVD. Participants in the "high" PA tertile reported more vigorous PA and walking, compared with participants in moderate and low tertiles (both P < 0.001). No differences were observed in daily household, occupational, or sedentary activities across PA tertiles. More participants in the "low" PA tertile were overweight/obese, had a history of prevalent diabetes, and/or had CVD compared with more active participants (all P < 0.001). Hierarchical modeling revealed that younger age (P = 0.002), cadaveric donor source (P = 0.006), shorter transplant vintage (P = 0.025), lower pulse pressure (P < 0.001), and no history of diabetes (P < 0.001) were associated with higher PA scores. CONCLUSION The most active KTR engaged in more intentional exercise. Lower levels of PA were positively associated with more CVD risk factors. Higher PA levels were associated with younger age and with more positive KTR outcomes.
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Affiliation(s)
- Augustine W Kang
- Department of Behavioral and Social Sciences, Brown University School of Public Health, Providence, RI.,Center for Health Equity Research, Brown University, Providence, RI
| | - Carol Ewing Garber
- Department of Biobehavioral Sciences, Teachers College, Columbia University, New York, NY
| | - Charles B Eaton
- Department of Family Medicine, Warren Alpert Medical School of Brown University, Providence, RI.,Center for Primary Care and Prevention, Kent Hospital, Warwick, RI.,Department of Epidemiology, Brown University School of Public Health, Providence, RI
| | - Patricia M Risica
- Department of Behavioral and Social Sciences, Brown University School of Public Health, Providence, RI.,Center for Health Equity Research, Brown University, Providence, RI.,Department of Epidemiology, Brown University School of Public Health, Providence, RI
| | - Andrew G Bostom
- Department of Family Medicine, Warren Alpert Medical School of Brown University, Providence, RI.,Center for Primary Care and Prevention, Kent Hospital, Warwick, RI
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Malhotra R, Katz R, Weiner DE, Levey AS, Cheung AK, Bostom AG, Ix JH. Blood Pressure, Chronic Kidney Disease Progression, and Kidney Allograft Failure in Kidney Transplant Recipients: A Secondary Analysis of the FAVORIT Trial. Am J Hypertens 2019; 32:816-823. [PMID: 31179500 DOI: 10.1093/ajh/hpz095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 06/07/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND In chronic kidney disease, intensive systolic blood pressure (SBP) control reduces mortality at a cost of greater acute kidney injury risk. Kidney transplantation involves implantation of denervated kidneys and immunosuppressive medications that increase acute kidney injury risk. The optimal blood pressure (BP) target in kidney transplant recipients (KTRs) is uncertain. Prior observational studies from the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) trial demonstrate associations of lower SBP levels and reduced mortality risk, but the relationship of BP with kidney allograft function remains unknown. Thus, in FAVORIT, we investigated the relationship of SBP and diastolic blood pressure (DBP) with risk of kidney allograft failure and estimated glomerular filtration rate (eGFR) slope among stable KTRs. METHODS Cox proportional hazards and multivariable linear regression models adjusted for demographics, transplant characteristics, comorbidities, baseline eGFR, and urine albumin-to-creatinine ratio were used to determine associations of SBP and DBP with time to a composite kidney outcome of ≥50% eGFR decline or dialysis dependence, and with annualized eGFR change, respectively. Multivariable restricted cubic spline plots were developed to evaluate the functional form of the relationships. RESULTS Among 3,598 KTRs, mean age was 52 ± 9 years, SBP was 136 ± 20 mm Hg, DBP was 79 ± 12 mm Hg, and eGFR was 49 ± 18 ml/minute/1.73 m2. There were 369 events of ≥50% eGFR decline or dialysis dependence during a mean follow-up of 4.0 ± 1.5 years. There was no association of either SBP (compared with SBP 120 to <130 mm Hg, hazard ratio (HR) for the SBP < 110 was 1.01 (95% confidence interval (CI) 0.60 to 1.70) and 130 to <140 was 0.89 (0.64 to 1.24)) or DBP (compared with DBP 70 to <80 mm Hg, HR for the DBP 60 to <70 was 1.00 (95% CI 0.74 to 1.34) and 80 to <90 was 0.90 (0.68 to 1.18)) with the kidney failure outcome or annualized eGFR slope, and, when examined using restricted cubic splines, there was no evidence of "J"- or "U"-shaped relationships. CONCLUSIONS In a large sample of stable KTRs, we found no evidence of thresholds at which lower BPs were related to higher risk of allograft failure or eGFR decline. In light of prior findings of mortality benefit at low SBP, these observational findings suggest lower BP may be beneficial in KTRs. This important question requires confirmation in future randomized trials in KTRs.
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Affiliation(s)
- Rakesh Malhotra
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, San Diego, California, USA
- Imperial Valley Family Care Medical Group, El Centro, California, USA
| | - Ronit Katz
- Kidney Research Institute, University of Washington, Seattle, Washington, USA
| | - Daniel E Weiner
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts, USA
| | - Andrew S Levey
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts, USA
| | - Alfred K Cheung
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
- Medical Service, Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, Utah, USA
| | - Andrew G Bostom
- Division of Hypertension and Kidney Diseases, Rhode Island Hospital, Providence, Rhode Island, USA
| | - Joachim H Ix
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, San Diego, California, USA
- Division of Preventive Medicine, Department of Family Medicine and Public Health, University of California San Diego, San Diego, California, USA
- Nephrology Section, Veterans Affairs San Diego Healthcare System, La Jolla, California, USA
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Weiner DE, Park M, Tighiouart H, Joseph AA, Carpenter MA, Goyal N, House AA, Hsu CY, Ix JH, Jacques PF, Kew CE, Kim SJ, Kusek JW, Pesavento TE, Pfeffer MA, Smith SR, Weir MR, Levey AS, Bostom AG. Albuminuria and Allograft Failure, Cardiovascular Disease Events, and All-Cause Death in Stable Kidney Transplant Recipients: A Cohort Analysis of the FAVORIT Trial. Am J Kidney Dis 2018; 73:51-61. [PMID: 30037726 DOI: 10.1053/j.ajkd.2018.05.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 05/23/2018] [Indexed: 12/30/2022]
Abstract
RATIONALE & OBJECTIVE Cardiovascular disease (CVD) is common and overall graft survival is suboptimal among kidney transplant recipients. Although albuminuria is a known risk factor for adverse outcomes among persons with native chronic kidney disease, the relationship of albuminuria with cardiovascular and kidney outcomes in transplant recipients is uncertain. STUDY DESIGN Post hoc longitudinal cohort analysis of the Folic Acid for Vascular Outcomes Reduction in Transplantation (FAVORIT) Trial. SETTING & PARTICIPANTS Stable kidney transplant recipients with elevated homocysteine levels from 30 sites in the United States, Canada, and Brazil. PREDICTOR Urine albumin-creatinine ratio (ACR) at randomization. OUTCOMES Allograft failure, CVD, and all-cause death. ANALYTICAL APPROACH Multivariable Cox models adjusted for age; sex; race; randomized treatment allocation; country; systolic and diastolic blood pressure; history of CVD, diabetes, and hypertension; smoking; cholesterol; body mass index; estimated glomerular filtration rate (eGFR); donor type; transplant vintage; medications; and immunosuppression. RESULTS Among 3,511 participants with complete data, median ACR was 24 (Q1-Q3, 9-98) mg/g, mean eGFR was 49±18 (standard deviation) mL/min/1.73m2, mean age was 52±9 years, and median graft vintage was 4.1 (Q1-Q3, 1.7-7.4) years. There were 1,017 (29%) with ACR < 10mg/g, 912 (26%) with ACR of 10 to 29mg/g, 1,134 (32%) with ACR of 30 to 299mg/g, and 448 (13%) with ACR ≥ 300mg/g. During approximately 4 years, 282 allograft failure events, 497 CVD events, and 407 deaths occurred. Event rates were higher at both lower eGFRs and higher ACR. ACR of 30 to 299 and ≥300mg/g relative to ACR < 10mg/g were independently associated with graft failure (HRs of 3.40 [95% CI, 2.19-5.30] and 9.96 [95% CI, 6.35-15.62], respectively), CVD events (HRs of 1.25 [95% CI, 0.96-1.61] and 1.55 [95% CI, 1.13-2.11], respectively), and all-cause death (HRs of 1.65 [95% CI, 1.23-2.21] and 2.07 [95% CI, 1.46-2.94], respectively). LIMITATIONS No data for rejection; single ACR assessment. CONCLUSIONS In a large population of stable kidney transplant recipients, elevated baseline ACR is independently associated with allograft failure, CVD, and death. Future studies are needed to evaluate whether reducing albuminuria improves these outcomes.
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Affiliation(s)
| | - Meyeon Park
- Division of Nephrology, University of California, San Francisco, San Francisco, CA
| | | | - Alin A Joseph
- Division of Nephrology, Tufts Medical Center, Boston, MA
| | - Myra A Carpenter
- Collaborative Studies Coordinating Center, University of North Carolina, Chapel Hill, NC
| | - Nitender Goyal
- Division of Nephrology, Tufts Medical Center, Boston, MA
| | - Andrew A House
- Division of Nephrology, London Health Sciences Centre, London, Ontario, Canada
| | - Chi-Yuan Hsu
- Division of Nephrology, University of California, San Francisco, San Francisco, CA
| | - Joachim H Ix
- Division of Nephrology-Hypertension, University of California, San Diego, San Diego, CA
| | - Paul F Jacques
- Human Nutrition Research Center on Aging, Tufts University, Boston, MA
| | - Clifton E Kew
- Division of Nephrology, University of Alabama, Birmingham, AL
| | - S Joseph Kim
- Division of Nephrology and the Kidney Transplant Program, Toronto General Hospital, Toronto, Ontario, Canada
| | - John W Kusek
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | | | - Marc A Pfeffer
- Cardiovascular Division, Brigham and Women's Hospital, Boston, MA
| | | | - Matthew R Weir
- Division of Nephrology, University of Maryland, Baltimore, MD
| | - Andrew S Levey
- Division of Nephrology, Tufts Medical Center, Boston, MA
| | - Andrew G Bostom
- Division of Hypertension and Kidney Diseases, Rhode Island Hospital, Providence, RI
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7
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Kalil RS, Carpenter MA, Ivanova A, Gravens-Mueller L, John AA, Weir MR, Pesavento T, Bostom AG, Pfeffer MA, Hunsicker LG. Impact of Hyperuricemia on Long-term Outcomes of Kidney Transplantation: Analysis of the FAVORIT Study. Am J Kidney Dis 2017; 70:762-769. [DOI: 10.1053/j.ajkd.2017.06.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 06/04/2017] [Indexed: 02/07/2023]
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Bostom AG, Merhi B, Walker J, Robinson-Bostom L. More than skin deep? Potential nicotinamide treatment applications in chronic kidney transplant recipients. World J Transplant 2016; 6:658-664. [PMID: 28058215 PMCID: PMC5175223 DOI: 10.5500/wjt.v6.i4.658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 10/03/2016] [Accepted: 11/02/2016] [Indexed: 02/05/2023] Open
Abstract
Non-melanoma cutaneous carcinomas, or skin cancers, predominantly squamous cell carcinomas (SCCs), are the most common malignancies occurring in kidney transplant recipients (KTRs). Squamous cell carcinoma risk is dramatically elevated in KTRs, occurring at rates of up 45-250 times those reported in general populations. New non-melanoma skin cancers in KTRs with a prior non-melanoma skin cancer also develop at 3-times the rate reported in non-KTRs with the same clinical history. The unique aggressiveness of SCCs in KTRs increases patient morbidity, due to the high rate of new lesions requiring treatment, frequently surgical excision. Oral nicotinamide shows promise in the chemoprevention of the especially aggressive non-melanoma skin cancers which occur in KTRs. This benefit might be conferred via its inhibition of sirtuin enzymatic pathways. Nicotinamide’s concurrent hypophosphatemic effect may also partially ameliorate the disturbed calcium-phosphorus homeostasis in these patients-a putative risk factor for mortality, and graft failure. Conceivably, a phase 3 trial of nicotinamide for the prevention of non-melanoma skin cancers in KTRs, lasting at least 12-mo, could also incorporate imaging and laboratory measures which assess nicotinamide’s impact on subclinical cardiovascular and chronic kidney disease risk, and progression.
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9
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Weir MR, Gravens-Muller L, Costa N, Ivanova A, Manitpisitkul W, Bostom AG, Diamantidis CJ. Safety events in kidney transplant recipients: results from the folic Acid for vascular outcome reduction in transplant trial. Transplantation 2015; 99:1003-8. [PMID: 25393158 DOI: 10.1097/tp.0000000000000454] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Kidney transplant recipients are at increased risk for adverse safety events related to their reduced renal function and many medications. METHODS We determined the incidence of adverse safety events based on previously defined Agency for Healthcare and Research Quality (AHRQ) International Classification of Diseases-9 (ICD-9) code-derived patient safety indicators (PSI) in the Folic Acid for Vascular Outcome Reduction in Transplant trial participants who had a hospitalization stratified by tertiles of estimated glomerular filtration rate (GFR). We also examined the frequency of Micromedex defined two precautionary drug-drug interactions, and two medications whose use may be contraindicated because of reduced GFR from the Folic Acid for Vascular Outcome Reduction in Transplant trial medication thesaurus at baseline, and annually among 4,110 participants. Logistic regression was used to examine the relationship between patient safety events and baseline demographic and clinical variables at a participant level. Event rates were estimated at participant and visit levels. RESULTS Of the 2,514 patients with a hospitalization, 978 (38.9%) experienced an AHRQ PSI. Factors which were associated with more common AHRQ PSI included: U.S. location, history of cardiovascular disease or diabetes, and lower tertile of estimated GFR. At a participant level, 2,524 of the 4,110 participants (61.4%) were taking calcineurin inhibitor and statin, 378 (9.2%) were taking azathioprine and an angiotensin-converting enzyme inhibitor, 171 (12.9%) were taking a sulfonylurea), 45 (3.4%) were taking metformin despite a baseline GFR below 40 mL per min per 1.73 m. CONCLUSION We conclude that patient safety events are not uncommon in kidney transplant recipients. Careful monitoring is necessary to prevent adverse outcomes.
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Affiliation(s)
- Matthew R Weir
- 1 Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD. 2 Department of Biostatistics, University of North Carolina, Chapel Hill, NC. 3 Department of Pharmacy, University of Maryland Medical Center, Baltimore, MD. 4 Rhode Island Hospital, Brown University School of Medicine, Providence, RI
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10
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Weiner DE, Carpenter MA, Levey AS, Ivanova A, Cole EH, Hunsicker L, Kasiske BL, Kim SJ, Kusek JW, Bostom AG. Kidney function and risk of cardiovascular disease and mortality in kidney transplant recipients: the FAVORIT trial. Am J Transplant 2012; 12:2437-45. [PMID: 22594581 PMCID: PMC3424309 DOI: 10.1111/j.1600-6143.2012.04101.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In kidney transplant recipients, cardiovascular disease (CVD) is the leading cause of death. The relationship of kidney function with CVD outcomes in transplant recipients remains uncertain. We performed a post hoc analysis of the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial to assess risk factors for CVD and mortality in kidney transplant recipients. Following adjustment for demographic, clinical and transplant characteristics, and traditional CVD risk factors, proportional hazards models were used to explore the association of estimated GFR with incident CVD and all-cause mortality. In 4016 participants, mean age was 52 years and 20% had prior CVD. Mean eGFR was 49 ± 18 mL/min/1.73 m(2) . In 3676 participants with complete data, there were 527 CVD events over a median of 3.8 years. Following adjustment, each 5 mL/min/1.73 m(2) higher eGFR at levels below 45 mL/min/1.73 m(2) was associated with a 15% lower risk of both CVD [HR = 0.85 (0.80, 0.90)] and death [HR = 0.85 (0.79, 0.90)], while there was no association between eGFR and outcomes at levels above 45 mL/min/1.73 m(2) . In conclusion, in stable kidney transplant recipients, lower eGFR is independently associated with adverse events, suggesting that reduced kidney function itself rather than preexisting comorbidity may lead to CVD.
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Affiliation(s)
| | | | | | | | | | | | - Bertram L Kasiske
- Hennepin County Medical Center and the University of Minnesota, Minneapolis, MN
| | | | - John W Kusek
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
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11
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Carpenter MA, Weir MR, Adey DB, House AA, Bostom AG, Kusek JW. Inadequacy of cardiovascular risk factor management in chronic kidney transplantation - evidence from the FAVORIT study. Clin Transplant 2012. [PMID: 22775763 DOI: 10.1111/j.1399-0012.2012.01676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Kidney transplant recipients (KTRs) have increased risk of cardiovascular disease (CVD). Our objective is to describe the prevalence of CVD risk factors applying standard criteria and use of CVD risk factor-lowering medications in contemporary KTRs. METHODS The Folic Acid for Vascular Outcome Reduction in Transplantation study enrolled and collected medication data on 4107 KTRs with elevated homocysteine and stable graft function an average of five yr post-transplant. RESULTS CVD risk factors were common (hypertension or use of blood pressure (BP) lowering medication in 92%, borderline or elevated low-density lipoprotein (LDL) or use of lipid-lowering agent in 66%, history of diabetes mellitus in 41%, and obesity in 38%); prevalent CVD was reported in 20% of study participants. National Kidney Foundation BP guidelines (BP <130/80 mmHg) were not met by 69% of participants. Uncontrolled hypertension (BP of 140/90 mmHg or higher) was present in 44% of those taking antihypertension medication; 18% of participants had borderline or elevated LDL, of which 60% were untreated, and 31% of the participants with prevalent CVD were not using an antiplatelet agent. CONCLUSION There is opportunity to improve treatment and control of traditional CVD risk factors in kidney transplant recipients.
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Affiliation(s)
- Myra A Carpenter
- Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA.
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Carpenter MA, Weir MR, Adey DB, House AA, Bostom AG, Kusek JW. Inadequacy of cardiovascular risk factor management in chronic kidney transplantation - evidence from the FAVORIT study. Clin Transplant 2012; 26:E438-46. [PMID: 22775763 DOI: 10.1111/j.1399-0012.2012.01676.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2012] [Indexed: 12/31/2022]
Abstract
BACKGROUND Kidney transplant recipients (KTRs) have increased risk of cardiovascular disease (CVD). Our objective is to describe the prevalence of CVD risk factors applying standard criteria and use of CVD risk factor-lowering medications in contemporary KTRs. METHODS The Folic Acid for Vascular Outcome Reduction in Transplantation study enrolled and collected medication data on 4107 KTRs with elevated homocysteine and stable graft function an average of five yr post-transplant. RESULTS CVD risk factors were common (hypertension or use of blood pressure (BP) lowering medication in 92%, borderline or elevated low-density lipoprotein (LDL) or use of lipid-lowering agent in 66%, history of diabetes mellitus in 41%, and obesity in 38%); prevalent CVD was reported in 20% of study participants. National Kidney Foundation BP guidelines (BP <130/80 mmHg) were not met by 69% of participants. Uncontrolled hypertension (BP of 140/90 mmHg or higher) was present in 44% of those taking antihypertension medication; 18% of participants had borderline or elevated LDL, of which 60% were untreated, and 31% of the participants with prevalent CVD were not using an antiplatelet agent. CONCLUSION There is opportunity to improve treatment and control of traditional CVD risk factors in kidney transplant recipients.
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Affiliation(s)
- Myra A Carpenter
- Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA.
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Bostom AG, Maclean AA, Maccubbin D, Tipping D, Giezek H, Hanlon WA. Extended-release niacin/laropiprant lowers serum phosphorus concentrations in patients with type 2 diabetes. J Clin Lipidol 2011; 5:281-7. [PMID: 21784373 DOI: 10.1016/j.jacl.2011.03.455] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 02/26/2011] [Accepted: 03/09/2011] [Indexed: 11/18/2022]
Abstract
BACKGROUND Niacin compounds lower serum phosphorus concentrations in patients with end-stage renal disease. METHODOLOGY We evaluated the impact of extended release niacin, given in fixed-dose combination with laropiprant, a specific inhibitor of prostaglandin-mediated, niacin-induced flushing, versus placebo, on serum phosphorus concentrations measured serially (at weeks 0, 4, 8, 12, 18, 24, 30, and 36) during a 36-week randomized, controlled trial. All subjects had a confirmed diagnosis of type 2 diabetes (n = 446 niacin/laropiprant; n = 339 placebo). Estimated glomerular filtration rate ranged from 36 to 184 mL/min/1.73 m(2), with n = 111 (14.1%) having a value <60 mL/min/1.73 m(2). Subjects received one tablet daily of extended-release niacin/laropiprant (1g niacin/ 20 mg laropiprant) for the first 4 weeks, and 2 tablets once daily, thereafter, or matched placebo. Niacin lowered serum phosphorus concentrations by 0.36 mg/dL (95% CI: -0.40, -0.31; P < .001), relative to placebo, from baseline values of 3.57 and 3.56 mg/dL in the niacin and placebo groups, respectively. Subgroup analyses revealed no evidence for phosphorus-lowering effect modification by these baseline variables: glomerular filtration rate <60 (n = 111;14.1%) vs ≥60 mL/min/m(2) (n = 674; 85.9%); phosphorus ≤3.5 mg/dL (n = 392; 49.9%) vs >3.5 mg/dL (n = 393; 50.1%); or prior statin use (n = 618; 78.7%) vs nonuse (n = 167; 21.3%). CONCLUSIONS AND IMPLICATIONS These data confirm that niacin's phosphorus-lowering effects-which may have therapeutic implications for the management of hyperphosphatemia and possible prevention of cardiorenal outcomes in renal disease-extend across a broad spectrum of renal function in type 2 diabetics without stage 4 or 5 chronic kidney disease (a glomerular filtration rate ≥30 mL/min/1.73 m(2)).
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Affiliation(s)
- Andrew G Bostom
- Rhode Island Hospital, Division of Kidney Diseases and Hypertension, 593 Eddy Street, Providence, RI 02903, USA.
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Garber C, Campbell SM, Carpenter MA, McKenney J, Bostom AG. Relationship Between Baseline Physical Activity, Self-reported Coronary Heart Disease (CHD) and CHD Risk Factors In Renal Transplant Recipients: Findings From The Folic Acid For Vascular Outcome Reduction In Transplantation (FAVORIT) Trial. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000403004.97475.c0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ix JH, Ganjoo P, Tipping D, Tershakovec AM, Bostom AG. Sustained hypophosphatemic effect of once-daily niacin/laropiprant in dyslipidemic CKD stage 3 patients. Am J Kidney Dis 2011; 57:963-5. [PMID: 21496982 DOI: 10.1053/j.ajkd.2011.03.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 03/09/2011] [Indexed: 02/04/2023]
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Bostom AG, Carpenter MA, Kusek JW, Levey AS, Hunsicker L, Pfeffer MA, Selhub J, Jacques PF, Cole E, Gravens-Mueller L, House AA, Kew C, McKenney JL, Pacheco-Silva A, Pesavento T, Pirsch J, Smith S, Solomon S, Weir M. Homocysteine-lowering and cardiovascular disease outcomes in kidney transplant recipients: primary results from the Folic Acid for Vascular Outcome Reduction in Transplantation trial. Circulation 2011; 123:1763-70. [PMID: 21482964 DOI: 10.1161/circulationaha.110.000588] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Kidney transplant recipients, like other patients with chronic kidney disease, experience excess risk of cardiovascular disease and elevated total homocysteine concentrations. Observational studies of patients with chronic kidney disease suggest increased homocysteine is a risk factor for cardiovascular disease. The impact of lowering total homocysteine levels in kidney transplant recipients is unknown. METHODS AND RESULTS In a double-blind controlled trial, we randomized 4110 stable kidney transplant recipients to a multivitamin that included either a high dose (n=2056) or low dose (n=2054) of folic acid, vitamin B6, and vitamin B12 to determine whether decreasing total homocysteine concentrations reduced the rate of the primary composite arteriosclerotic cardiovascular disease outcome (myocardial infarction, stroke, cardiovascular disease death, resuscitated sudden death, coronary artery or renal artery revascularization, lower-extremity arterial disease, carotid endarterectomy or angioplasty, or abdominal aortic aneurysm repair). Mean follow-up was 4.0 years. Treatment with the high-dose multivitamin reduced homocysteine but did not reduce the rates of the primary outcome (n=547 total events; hazards ratio [95 confidence interval]=0.99 [0.84 to 1.17]), secondary outcomes of all-cause mortality (n=431 deaths; 1.04 [0.86 to 1.26]), or dialysis-dependent kidney failure (n=343 events; 1.15 [0.93 to 1.43]) compared to the low-dose multivitamin. CONCLUSIONS Treatment with a high-dose folic acid, B6, and B12 multivitamin in kidney transplant recipients did not reduce a composite cardiovascular disease outcome, all-cause mortality, or dialysis-dependent kidney failure despite significant reduction in homocysteine level.
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Affiliation(s)
- Andrew G Bostom
- Rhode Island Hospital, 110 Lockwood Street, Providence, RI 02903, USA.
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Ganjoo P, Tipping D, Tershakovec AM, Bostom AG. 42 Extended-Release Niacin/Laropiprant Lowers Serum Phosphorus Levels in Dyslipidemic Patients with Stage 3 Chronic Kidney Disease (CKD). Am J Kidney Dis 2011. [DOI: 10.1053/j.ajkd.2011.02.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hu S, Shearer GC, Steffes MW, Harris WS, Bostom AG. Once-daily extended-release niacin lowers serum phosphorus concentrations in patients with metabolic syndrome dyslipidemia. Am J Kidney Dis 2010; 57:181-2. [PMID: 20888102 DOI: 10.1053/j.ajkd.2010.06.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 06/11/2010] [Indexed: 02/04/2023]
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Bostom AG, MacLean A, Maccubbin D, Tipping D, Gizek H, Hanlon W. Extended-Release Niacin/Laropiprant Lowers Serum Phosphorus Concentrations in Patients with Type 2 Diabetes and Mild Hyperphosphatemia. J Clin Lipidol 2010. [DOI: 10.1016/j.jacl.2010.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Maccubbin D, Tipping D, Kuznetsova O, Hanlon WA, Bostom AG. Hypophosphatemic effect of niacin in patients without renal failure: a randomized trial. Clin J Am Soc Nephrol 2010; 5:582-9. [PMID: 20299362 DOI: 10.2215/cjn.07341009] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND OBJECTIVES Niacin administration lowers the marked hyperphosphatemia that is characteristic of renal failure. We examined whether niacin administration also reduces serum phosphorus concentrations in patients who have dyslipidemia and are free of advanced renal disease. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We performed a post hoc data analysis of serum phosphorus concentrations that had been determined serially (at baseline and weeks 4, 8, 12, 18, and 24) among 1547 patients who had dyslipidemia and were randomly assigned in a 3:2:1 ratio to treatment with extended release niacin (ERN; 1 g/d for 4 weeks and dose advanced to 2 g/d for 20 weeks) combined with the selective prostaglandin D2 receptor subtype 1 inhibitor laropiprant (L; n = 761), ERN alone (n = 518), or placebo (n = 268). RESULTS Repeated measures analysis revealed that ERN-L treatment resulted in a net mean (95% confidence interval) serum phosphorus change comparing ERN-L with placebo treatment of -0.13 mmol/L (-0.15 to -0.13 mmol/L; -0.41 mg/dl [-0.46 to -0.37 mg/dl]). These results were consistent across the subgroups defined by estimated GFR of <60 or > or =60 ml/min per 1.73 m(2), a serum phosphorus of >1.13 mmol/L (3.5 mg/dl) versus < or =1.13 mmol/L (3.5 mg/dl), the presence of clinical diabetes, or concomitant statin use. CONCLUSIONS We have provided definitive evidence that once-daily ERN-L treatment causes a sustained 0.13-mmol/L (0.4-mg/dl) reduction in serum phosphorus concentrations, approximately 10% from baseline, which is unaffected by estimated GFR ranging from 30 to > or =90 ml/min per 1.73 m(2) (i.e., stages 1 through 3 chronic kidney disease).
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Affiliation(s)
- Darbie Maccubbin
- Rhode Island Hospital, Division of Kidney Diseases and Hypertension, 593 Eddy Street, Providence, RI, 02903, USA
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Bostom AG, Maccubbin D, Tipping D, Kuznetsova O, Hanlon WA. EXTENDED-RELEASE NIACIN/LAROPIPRANT LOWERS SERUM PHOSPHORUS CONCENTRATIONS IN DYSLIPIDEMIC PATIENTS. J Am Coll Cardiol 2010. [DOI: 10.1016/s0735-1097(10)60515-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bostom AG, Carpenter MA, Hunsicker L, Jacques PF, Kusek JW, Levey AS, McKenney JL, Mercier RY, Pfeffer MA, Selhub J. Baseline characteristics of participants in the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial. Am J Kidney Dis 2008; 53:121-8. [PMID: 19022547 DOI: 10.1053/j.ajkd.2008.08.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 08/07/2008] [Indexed: 12/31/2022]
Abstract
BACKGROUND Hyperhomocysteinemia may be a modifiable risk factor for the prevention of arteriosclerotic outcomes in patients with chronic kidney disease (CKD). Few clinical trials of homocysteine lowering have been conducted in persons with CKD before reaching end-stage renal disease. Kidney transplant recipients are considered individuals with CKD. OBJECTIVES To describe the baseline characteristics of renal transplant recipients enrolled in a clinical trial of homocysteine lowering with a standard multivitamin containing high doses of folic acid and vitamins B(6) and B(12) aimed at reducing arteriosclerotic outcomes. Factors considered were level of kidney function, total homocysteine concentration, and prevalence of diabetes and previous cardiovascular disease (CVD). STUDY DESIGN Cross-sectional survey within a randomized controlled trial cohort. SETTING & PARTICIPANTS Participants were recruited from kidney transplant clinics in the United States, Canada, and Brazil. Eligible participants had increased levels of homocysteine (> or =12.0 micromol/L in men and > or =11.0 micromol/L in women) and kidney function measured by means of Cockroft-Gault estimated creatinine clearance of 30 mL/min or greater. RESULTS Of 4,110 randomly assigned participants, 38.9% had diabetes and 19.5% had previous CVD. Mean total homocysteine concentration was 17.1 +/- 6.3 (SD) micromol/L, whereas mean creatinine clearance was 66.4 +/- 23.2 mL/min. Approximately 90% of the trial cohort had an estimated glomerular filtration rate consistent with stages 2 to 3 CKD (i.e., 30 to 89 mL/min). LIMITATIONS Analysis is based on cross-sectional data from a randomized controlled trial, self-report of comorbid illnesses, and level of kidney function was estimated. CONCLUSIONS A large population of stable renal transplant recipients who are at high risk of the development of CVD (both de novo and recurrent) has been recruited into the Folic Acid for Vascular Outcome Reduction in Transplantation Trial and are likely to experience a sufficient number of events to address the primary hypothesis of the trial.
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Affiliation(s)
- Andrew G Bostom
- Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903, USA
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Bostom AG, Carpenter MA, Kusek JW, Hunsicker LG, Pfeffer MA, Levey AS, Jacques PF, McKenney J. Rationale and design of the Folic Acid for Vascular Outcome Reduction In Transplantation (FAVORIT) trial. Am Heart J 2006; 152:448.e1-7. [PMID: 16923411 DOI: 10.1016/j.ahj.2006.03.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 03/07/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Patients with chronic kidney disease, including kidney transplant recipients, are at high risk for cardiovascular disease (CVD). In addition to the constellation of traditional CVD risk factors in chronic kidney disease, elevated total homocysteine (tHcy) is notably more prevalent among the general population. The Folic Acid for Vascular Outcome Reduction In Transplantation (FAVORIT) trial is designed to evaluate whether lowering tHcy using vitamin supplementation reduces CVD events in renal transplant recipients. METHODS FAVORIT is a multicenter double-blind randomized controlled clinical trial. Participants are clinically stable renal transplant recipients who are 6 months or longer posttransplant with elevated tHcy. Patients are randomized to a multivitamin that includes either a high-dose or low-dose of folic acid (5 or 0 mg), vitamin B6 (50 or 1.4 mg), and vitamin B12 (1000 or 2 microg). The primary end point is a composite of incident or recurrent CVD outcomes, that is, coronary heart, cerebrovascular, or abdominal aortic/lower extremity arterial events. A sample size of 4000 is estimated to provide 87% power to detect a 20% treatment effect. Recruitment is expected to continue until July 2006, with follow-up through June 2010. RESULTS From August 2002 through December 2004, 2234 of the target 4000 patients were enrolled. In accordance with trial design, mean (SD) screening tHcy was elevated (17.4 +/- 6.2 micromol/L), and mean (SD) estimated creatinine clearance was consistent with stable renal function (58.0 +/- 18.6 mL/min). Evaluating baseline results to date, 42% of the randomized participants had a history of diabetes mellitus, and 21% had prevalent CVD. CONCLUSIONS The FAVORIT trial is designed with sufficient power and follow-up time to detect a clinically relevant change in CVD risk between renal transplant recipients receiving a high or low tHcy-lowering folic acid multivitamin. Preliminary screening and baseline data support the trial's objectives.
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Affiliation(s)
- Daniel H. Fisher
- a Higuchi Biosciences Center for Bioanalytical Research, University of Kansas , Lawrence , KS , 66047
| | - Andrew G. Bostom
- b Vitamin Bioavailability Laboratory, The Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts New England Medical Center , Boston , MA , 02111
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Abstract
BACKGROUND The inflammatory marker C-reactive protein (CRP) has been found in most, but not all, prospective studies to be associated with future cardiovascular outcomes. However, CRP has not been tested in the high-cardiovascular risk population of type 2 diabetic nephropathy. METHODS We studied the independent relationship between CRP and the subsequent development of incident or recurrent arteriosclerotic outcomes (primary) and congestive heart failure events (secondary) in 1560 individuals with diabetic nephropathy, overt proteinuria, and hypertension enrolled in the prospective Irbesartan Diabetic Nephropathy Trial. RESULTS Traditional cardiac risk factors were highly prevalent, CRP levels were high overall [quintiles (mg/L) 1st, 0 to 1.2; 2nd, 1.3 to 2.5; 3rd, 2.6 to 5.0; 4th, 5.1 to 10.0; and 5th, >10), and subsequent cardiovascular events were very common. A univariate relationship existed between CRP and total arteriosclerotic outcomes (P < 0.0001). However, after adjusting for study intervention and traditional risk factors, the relationship no longer remained. In fact, controlling for previous cardiovascular disease alone caused the association to become nonsignificant. The secondary analysis found a significant univariate relationship between CRP and congestive heart failure events (P= 0.007) that persisted in multivariate analyses (P= 0.006). However, this relationship was confined to the highest CRP quintile [RR (95% CI) 2.0 (1.27, 3.16)]. CONCLUSION In diabetic patients with nephropathy, CRP does not add predictive information above and beyond that provided by traditional established risk factors. Whether this holds true for other populations with similar risk burdens is an important public health question that should be addressed. A secondary finding of a link between CRP and congestive heart failure requires further confirmation.
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Affiliation(s)
- Allon N Friedman
- Division of Nephrology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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Friedman AN, Hunsicker LG, Selhub J, Bostom AG. Total plasma homocysteine and arteriosclerotic outcomes in type 2 diabetes with nephropathy. J Am Soc Nephrol 2005; 16:3397-402. [PMID: 16162814 DOI: 10.1681/asn.2004100846] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Total serum homocysteine (tHcy) has been shown to predict de novo and recurrent cardiovascular events in many studies. However, results in diabetic populations with minimal nephropathy are mixed. The independent relationship between tHcy and arteriosclerotic outcomes and congestive heart failure (CHF) events in a population with high cardiovascular risk and diabetic nephropathy was examined. A total of 1575 individuals were enrolled in the international Irbesartan Diabetic Nephropathy Trial (IDNT) and followed for 2.6 yr. All participants had baseline diabetic nephropathy, overt proteinuria, and hypertension and were recruited between 1996 and 1999. A total of 492 total arteriosclerotic outcomes (primary outcome) and 317 CHF events (secondary outcome) were tallied. Established cardiovascular risk factors were highly prevalent, as were high tHcy levels (quintiles [microM]: first 4.5 to 11; second >11 to 13; third >13 to 15; fourth >15 to 19; fifth >19). No association between tHcy and arteriosclerotic outcomes was observed in a univariate model or after adjustment for study randomization and established cardiovascular risk factors. The strongest outcome predictor was the presence of baseline cardiovascular disease, followed by an inverse relationship to diastolic BP. The significant univariate association between tHcy and CHF events disappeared when serum creatinine alone was added to the model. These findings question the utility of tHcy in predicting de novo or recurrent cardiovascular events in individuals with diabetic nephropathy. Further studies are needed to confirm whether these negative results apply to other populations with heavy cardiovascular risk burdens. Previous positive findings can potentially be explained through tHcy's role as a sensitive surrogate marker for kidney disease, itself a recognized cardiovascular risk factor.
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Affiliation(s)
- Allon N Friedman
- Division of Nephrology, Indiana University School of Medicine, 1481 W. 10th Street-111N, Indianapolis, IN 46202, USA.
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Abstract
BACKGROUND Patients with diabetic nephropathy are at elevated cardiovascular risk. C-reactive protein (CRP) has been used to successfully predict cardiovascular events. OBJECTIVE We identified clinical and biochemical characteristics that correlate with CRP levels in diabetic nephropathy patients. DESIGN Baseline data obtained from 722 patients in the Irbesartan Diabetic Nephropathy Trial included age, sex, body mass index (BMI), systolic blood pressure (BP), serum creatinine, plasma low- and high-density cholesterol, triacylglycerol, serum albumin, hemoglobin A1C, 24h urinary protein excretion, plasma total homocysteine (tHcy), folate, B12, pyridoxal 5'-phosphate (PLP, active form of Vitamin B(6)), and plasma CRP levels. RESULTS In univariate analyses CRP was positively associated with female sex (r=0.08; P=0.04), BMI (r=0.34; P<0.01), serum creatinine (r=0.21; P<0.01), hemoglobin A1C (r=0.08; 0.04), and inversely associated with PLP (r=-0.17; P<0.01) and folate (r=-0.09; P=0.02). A stepwise multiple regression model found CRP directly correlated with BMI (P<0.01) and serum creatinine (P<0.01), and inversely correlated with PLP (P<0.01). The final model explained 16% of the total variance of CRP. CONCLUSIONS These results extend previous findings of an inverse relationship between Vitamin B(6) and CRP. The lack of association between CRP and certain established or emerging cardiovascular risk factors offers novel information regarding cardiovascular risk in this population.
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Affiliation(s)
- Allon N Friedman
- Division of Nephrology, Indiana University School of Medicine, 1481 W. 10th St.-111N, Indianapolis, IN 46202, USA.
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Friedman AN, Bostom AG, Laliberty P, Selhub J, Shemin D. The effect of N-acetylcysteine on plasma total homocysteine levels in hemodialysis: a randomized, controlled study. Am J Kidney Dis 2003; 41:442-6. [PMID: 12552508 DOI: 10.1053/ajkd.2003.50054] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND The chronic hemodialysis population has an accelerated rate of cardiovascular morbidity and death. Furthermore, elevated levels of the putative atherothrombotic risk factor homocysteine are almost ubiquitous in this population. Attempts to normalize elevated plasma total homocysteine (tHcy) levels in dialysis patients using pharmacological-dose vitamin therapy or other strategies generally have been unsuccessful. Preliminary uncontrolled evidence suggests that N-acetylcysteine (NAC) may be an effective tHcy-lowering agent. We designed a randomized placebo-controlled study to determine the effect of prolonged oral NAC therapy on lowering tHcy levels in vitamin-replete chronic hemodialysis patients. METHODS Thirty-eight subjects were treated before intervention with a standard dialysis vitamin supplement to ensure a uniform vitamin-replete state. They were then block randomized to treatment with NAC, 1.2 g twice a day, for 4 weeks or matched placebo. RESULTS There were no significant baseline differences between the two groups, although differences in pyridoxal 5'-phosphate (active form of vitamin B(6)) levels approached significance (P = 0.06). In a paired analysis, there was no statistically significant difference between the NAC and placebo groups. NAC was very well tolerated in hemodialysis patients. CONCLUSION This randomized placebo-controlled trial found that chronic oral NAC therapy did not significantly reduce tHcy levels in hemodialysis patients. Although a larger sample size theoretically could have increased the statistical significance between groups, implications of the potentially very modest reduction in tHcy levels are not yet known. Finally, based on this limited study, NAC appears to be a safe and well-tolerated therapy in the hemodialysis population.
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Affiliation(s)
- Allon N Friedman
- Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA.
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Jacques PF, Bostom AG, Selhub J, Rich S, Ellison RC, Eckfeldt JH, Gravel RA, Rozen R. Effects of polymorphisms of methionine synthase and methionine synthase reductase on total plasma homocysteine in the NHLBI Family Heart Study. Atherosclerosis 2003; 166:49-55. [PMID: 12482550 DOI: 10.1016/s0021-9150(02)00204-6] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The metabolism of homocysteine requires contributions of several enzymes and vitamin cofactors. Earlier studies identified a common polymorphism of methylenetetrahydrofolate reductase that was associated with mild hyperhomocysteinemia. Common variants of two other enzymes involved in homocysteine metabolism, methionine synthase and methionine synthase reductase, have also been identified. Methionine synthase catalyzes the remethylation of homocysteine to form methionine and methionine synthase reductase is required for the reductive activation of the cobalamin-dependent methionine synthase. The methionine synthase gene (MTR) mutation is an A to G substitution, 2756A-->G, which converts an aspartate to a glycine codon. The methionine synthase reductase gene (MTRR) mutation is an A to G substitution, 66A-->G, that converts an isoleucine to a methionine residue. To determine if these polymorphisms were associated with mild hyperhomocysteinemia, we investigated subjects from two of the NHLBI Family Heart Study field centers, Framingham and Utah. Total plasma homocysteine concentrations were determined after an overnight fast and after a 4-h methionine load test. MTR and MTRR genotype data were available for 677 and 562 subjects, respectively. The geometric mean fasting homocysteine was unrelated to the MTR or MTRR genotype categories (AA, AG, GG). After a methionine load, a weak positive association was observed between change in homocysteine after a methionine load and the number of mutant MTR alleles (P-trend=0.04), but this association was not statistically significant according to the overall F-statistic (P=0.12). There was no significant interaction between MTR and MTRR genotype or between these genotypes and any of the vitamins with respect to homocysteine concentrations. This study provides no evidence that these common MTR and MTRR mutations are associated with alterations in plasma homocysteine.
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Affiliation(s)
- Paul F Jacques
- Jean Mayer USDA, Human Nutrition Research Center on Aging at Tufts University, 711 Wasington Street, Boston, MA 02111, USA.
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Ghandour H, Bagley PJ, Shemin D, Hsu N, Jacques PF, Dworkin L, Bostom AG, Selhub J. Distribution of plasma folate forms in hemodialysis patients receiving high daily doses of L-folinic or folic acid. Kidney Int 2002; 62:2246-9. [PMID: 12427152 DOI: 10.1046/j.1523-1755.2002.00666.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND We have previously reported that a daily oral high dose of l-folinic acid for the treatment of hyperhomocysteinemia in hemodialysis patients does not provide significantly greater reduction in fasting total homocysteine (tHcy) levels than an equimolar dose of folic acid. The present study uses the affinity/HPLC method to analyze the distribution of plasma folate forms in patients who received l-folinic acid versus those who received folic acid. This was done to investigate claims that renal insufficiency is associated with impaired folate interconversion, a stance that is supportive of the premise that tHcy lowering in these patients is more efficacious with folinic acid and other reduced folates, than folic acid. METHODS Forty-eight chronic and stable hemodialysis patients were block-randomized, based on their screening predialysis tHcy levels, sex, and dialysis center, into two groups treated for 12 weeks with oral folic acid at 15 mg/day or an equimolar amount (20 mg/day) of oral l-folinic acid. All 48 subjects also received 50 mg/day of oral vitamin B6 and 1 mg/day of oral vitamin B12. Folate distribution was determined in plasma of 46 participants (Folinic acid group, N = 22; Folic acid group, N = 24) by using the affinity/HPLC method, with electrochemical (coulometric) detection. RESULTS Both groups had similar baseline geometric means of plasma total folate and similar folate forms distribution. Following treatment, both groups demonstrated similar marked elevation in plasma total folate (geometric mean of the increase: Folinic acid group, +337 ng/mL; Folic acid group, +312 ng/mL; P = 0.796). In the folinic acid-treated group, practically all of the increase in total folate was due to 5-methyltetrahydrofolate. In the folic acid-treated group 5-methyltetrahydrofolate accounted for 35% of the increase in total folate and the remainder was unmethylated folic acid. CONCLUSIONS Data from the present findings suggest that defects in folate absorption or impairment in folate interconversion are not the cause of the persistent hyperhomocysteinemia in hemodialysis patients.
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Affiliation(s)
- Haifa Ghandour
- Vitamin Metabolism, Jean Mayer United States Department of Agriculture, Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111, USA
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Tofler GH, D'Agostino RB, Jacques PF, Bostom AG, Wilson PWF, Lipinska I, Mittleman MA, Selhub J. Association between increased homocysteine levels and impaired fibrinolytic potential: potential mechanism for cardiovascular risk. Thromb Haemost 2002; 88:799-804. [PMID: 12428097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
BACKGROUND Elevated homocysteine levels increase cardiovascular risk although the mechanism is not well understood. Since thrombosis plays an important role in plaque development and acute coronary syndromes, hyperhomocysteinemia may increase risk by increasing the thrombotic potential. METHODS AND RESULTS Hemostatic risk factors were measured in 3,216 individuals (1,451 men and 1,765 women) free of cardiovascular disease who participated in cycle 5 of the Framingham Offspring Study. An increase in homocysteine level was associated with a rise in plasminogen activator inhibitor (PAI-1), tissue plasminogen activator (TPA) antigen, von Willebrand factor and fibrinogen level. After regression analyses adjusting for covariates, there remained significant associations between homocysteine and PAI-1 and TPA antigen. CONCLUSION Increasing homocysteine levels are associated with impaired fibrinolytic potential, as indicated by increased PAI-1 and TPA antigen levels. These data suggest that folic acid and other homocysteine lowering therapies may decrease cardiac events through a reduction in thrombotic tendency.
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Abstract
OBJECTIVE Patients with diabetes who manifest proteinuria are at increased risk for cardiovascular events. Some studies suggest that proteinuria exerts its cardiovascular effects at least partly through a positive association with total plasma homocysteine (tHcy). Modestly sized but better designed contrary studies find no such link through a limited range of serum creatinine and proteinuria. We tested the hypothesis that proteinuria independently predicts tHcy levels in a larger cohort of type 2 diabetic patients with nephropathy throughout a much broader range of kidney disease and proteinuria. RESEARCH DESIGN AND METHODS Baseline data for the cross-sectional study were obtained from 717 patients enrolled in the multicenter Irbesartan Diabetic Nephropathy Trial. All subjects had type 2 diabetes, hypertension, and proteinuria and were between 29 and 78 years of age. Data included age, sex, BMI, serum creatinine and albumin, LDL and HDL cholesterol, triglyceride, proteinuria and albuminuria, plasma folate, B12, and pyridoxal 5'-phosphate (PLP) (the active form of B6), HbA(1c), and tHcy levels. Unadjusted and multivariable models were used in the analysis. RESULTS Crude analyses revealed significant associations between tHcy and age (r = 0.074; P = 0.008), creatinine (r = 0.414; P < 0.001), PLP (r = -0.105; P = 0.021), B12 (r = -0.216; P < 0.001), folate (r = -0.241; P < 0.001), and HbA(1c) (r = -0.119; P = 0.003), with serum albumin approaching significance (r = 0.055; P = 0.072). Only serum creatinine, plasma folate, B12, serum albumin, sex, HbA(1c), and age were independent predictors of tHcy after controlling for all other variables. CONCLUSIONS By finding no independent correlation between proteinuria (or albuminuria) and tHcy levels, this study improves the external validity of previous negative findings. Therefore, it is unlikely that the observed positive association between proteinuria and cardiovascular disease is directly related to hyperhomocysteinemia.
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Affiliation(s)
- Allon N Friedman
- Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111, USA.
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Bostom AG, Kronenberg F, Ritz E. Predictive performance of renal function equations for patients with chronic kidney disease and normal serum creatinine levels. J Am Soc Nephrol 2002; 13:2140-4. [PMID: 12138147 DOI: 10.1097/01.asn.0000022011.35035.f3] [Citation(s) in RCA: 281] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Accurate renal function measurements are important for the diagnosis and treatment of kidney disease, proper medication dosing, interpretation of possible uremic symptoms, and decision-making regarding when to initiate renal replacement therapy. Because the use of highly accurate filtration markers to measure renal function has traditionally been limited by cumbersome and costly techniques and the involvement of radioactivity (among other factors), renal function is typically estimated by using specially derived prediction equations. These formulae usually use serum creatinine levels, i.e., a marker of filtration that is insensitive to mild/moderate decreases in GFR. Although attempts have been made to validate certain renal function prediction equations among patients with chronic kidney disease (CKD) with abnormal serum creatinine levels, this is the first study to specifically evaluate the predictive performance of these equations for patients with CKD and serum creatinine levels in the normal range. The results of eight prediction equations for 109 patients with CKD and serum creatinine levels of < or =1.5 mg/dl were compared with standard iohexol GFR values. The most accurate results were obtained with the Cockroft-Gault and Bjornsson equations. The most precise formulae were the Modification of Diet in Renal Disease Study equations, although they were highly biased. Even the most accurate results exhibited levels of error that made them suboptimal for clinical treatment of these patients. These results suggest that measurement of GFR with endogenous or exogenous filtration markers might be the most prudent strategy for the assessment of renal function in the CKD population with normal serum creatinine levels. Further studies are needed to confirm the generalizability of these findings for this patient subgroup.
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Affiliation(s)
- Andrew G Bostom
- Division of Renal Diseases, Rhode Island Hospital, Providence, Rhode Island 02903, USA.
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Bostom AG, Sharaf B. B vitamins and restenosis after coronary angioplasty. N Engl J Med 2002; 346:1093-5. [PMID: 11936123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
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Abstract
Renal transplantation is a commonly performed curative procedure for end-stage renal disease. With the increase in renal allograft half-lives, attention is now being focused on cardiovascular morbidity and death in the renal transplant recipient (RTR) population. Among the more novel cardiovascular disease (CVD) risk factors for which this group is at risk is hyperhomocysteinemia. Hyperhomocysteinemia has been associated with an increased risk of CVD, although prospective randomized trials designed to prove causality are still ongoing. Since plasma total homocysteine levels are inversely related to renal function, RTRs have a greatly increased prevalence of hyperhomocysteinemia. Other determinants of homocysteine include B-vitamins, albumin, age, and genetic polymorphisms. Although RTRs are resistant to the typical B-vitamin doses used to correct hyperhomocysteinemia in the general population, they do respond to supraphysiologic dose therapy. In terms of prevalence, etiology, and treatment of hyperhomocysteinemia, RTRs are very similar to the much larger chronic renal insufficiency population. For this reason, RTRs have been chosen as an ideal study population in investigating the effect of reducing hyperhomocysteinemia on CVD outcomes.
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Affiliation(s)
- Allon N Friedman
- Vitamin Metabolism and Aging, Tufts Jean Mayer USDA HNRCA, Boston, MA, USA.
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Audelin MC, Selhub J, Bostom AG, Schaefer EJ, Collins D, Nadeau M, Rinfret S, McNamara JR. Hyperhomocysteinemia and cardiovascular disease in diabetes mellitus patients. J Am Coll Cardiol 2002. [DOI: 10.1016/s0735-1097(02)81131-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Bostom AG, Jacques PF, Liaugaudas G, Rogers G, Rosenberg IH, Selhub J. Total homocysteine lowering treatment among coronary artery disease patients in the era of folic acid-fortified cereal grain flour. Arterioscler Thromb Vasc Biol 2002; 22:488-91. [PMID: 11884295 DOI: 10.1161/hq0302.105369] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The prevalence of deficient plasma folate status and elevated total plasma levels of homocysteine (tHcy), have been dramatically reduced after fortification of all enriched cereal grain flour products with folic acid at 140 microg/100 g flour. Against this new background fortification, we evaluated the tHcy-lowering efficacy of pharmacological dose, folic acid-based vitamin B supplementation among stable coronary artery disease (CAD) patients. Using a 2x2 factorial design, 131 stable CAD patients (mean age 60.1 years; 29.8% women) were randomly assigned to receive a combination of folic acid 2.5 mg/d, riboflavin 5 mg/d, + B12 0.4 mg/d, or placebo, with or without vitamin B6 50 mg/d, for 12 weeks of treatment. ANCOVA adjusted for baseline fasting tHcy levels revealed only very modest (ie, approximately 1.0 micromol/L), albeit statistically significant (P<0.05), reductions in mean fasting tHcy levels afforded by the folic acid-containing treatments. Additional analyses indicated that none of the treatments provided a statistically significant reduction in the 2-hour post-methionine increase in tHcy levels, relative to placebo treatment. CAD patients exposed to cereal grain flour products fortified with folic acid who receive high-dose, folic acid-containing vitamin B regimens, experience only very modest reductions in their mean fasting plasma tHcy levels. These findings have important implications for the statistical power of clinical trials testing the hypothesis that tHcy-lowering treatment may reduce recurrent atherothrombotic event rates.
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Affiliation(s)
- Andrew G Bostom
- Division of Renal Diseases, Rhode Island Hospital, Providence 02903, USA.
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Friedman AN, Bostom AG, Levey AS, Rosenberg IH, Selhub J, Pierratos A. Plasma total homocysteine levels among patients undergoing nocturnal versus standard hemodialysis. J Am Soc Nephrol 2002; 13:265-268. [PMID: 11752047 DOI: 10.1681/asn.v131265] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Mild hyperhomocysteinemia, a putative risk factor for arteriosclerotic outcomes, is seen in >85% of hemodialysis patients. Therapeutic strategies, including pharmacologic-dose B vitamin supplementation and "high-flux" or "super-flux" hemodialysis, have consistently failed to normalize total homocysteine (tHcy) levels in these patients. Predialysis plasma tHcy levels in 23 patients who were undergoing nocturnal hemodialysis (NHD) six or seven nights/wk were compared with those in 31 patients from the same Canadian dialysis unit who were undergoing chronic standard hemodialysis (SHD) (all <65 yr of age, undergoing thrice-weekly treatments). The SHD patients were similar to typical North American chronic hemodialysis patients with respect to B vitamin status and albumin, creatinine, and tHcy levels. Geometric mean tHcy levels for the NHD patients were significantly lower (12.7 versus 20.0 microM, P < 0.0001), as was the prevalence of mild-to-moderate hyperhomocysteinemia (>12 microM; NHD, 57%; SHD, 94%; P = 0.002). Analysis of covariance adjusted for plasma folate, vitamin B12, and pyridoxal 5'-phosphate levels, age, and gender confirmed that NHD was independently associated with 6.0 microM lower geometric mean tHcy levels (P = 0.001). It is concluded that tHcy levels are significantly lower among NHD patients, compared with SHD patients. Clinical trials will be necessary to confirm that NHD is effective in reducing tHcy levels among patients with dialysis-dependent end-stage renal disease.
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Affiliation(s)
- Allon N Friedman
- *Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts; Division of Nephrology, Tufts-New England Medical Center, Boston, Massachusetts; Division of Renal Diseases, Rhode Island Hospital, Providence, Rhode Island; and Humber River Regional Hospital, University of Toronto, Toronto, Canada
| | - Andrew G Bostom
- *Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts; Division of Nephrology, Tufts-New England Medical Center, Boston, Massachusetts; Division of Renal Diseases, Rhode Island Hospital, Providence, Rhode Island; and Humber River Regional Hospital, University of Toronto, Toronto, Canada
| | - Andrew S Levey
- *Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts; Division of Nephrology, Tufts-New England Medical Center, Boston, Massachusetts; Division of Renal Diseases, Rhode Island Hospital, Providence, Rhode Island; and Humber River Regional Hospital, University of Toronto, Toronto, Canada
| | - Irwin H Rosenberg
- *Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts; Division of Nephrology, Tufts-New England Medical Center, Boston, Massachusetts; Division of Renal Diseases, Rhode Island Hospital, Providence, Rhode Island; and Humber River Regional Hospital, University of Toronto, Toronto, Canada
| | - Jacob Selhub
- *Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts; Division of Nephrology, Tufts-New England Medical Center, Boston, Massachusetts; Division of Renal Diseases, Rhode Island Hospital, Providence, Rhode Island; and Humber River Regional Hospital, University of Toronto, Toronto, Canada
| | - Andreas Pierratos
- *Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts; Division of Nephrology, Tufts-New England Medical Center, Boston, Massachusetts; Division of Renal Diseases, Rhode Island Hospital, Providence, Rhode Island; and Humber River Regional Hospital, University of Toronto, Toronto, Canada
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Bostom AG, Kronenberg F, Jacques PF, Kuen E, Ritz E, König P, Kraatz G, Lhotta K, Mann JF, Müller GA, Neyer U, Riegel W, Schwenger V, Riegler P, Selhub J. Proteinuria and plasma total homocysteine levels in chronic renal disease patients with a normal range serum creatinine: critical impact of true glomerular filtration rate. Atherosclerosis 2001; 159:219-23. [PMID: 11689224 DOI: 10.1016/s0021-9150(01)00502-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Conflicting data have been reported concerning the independent association between proteinuria and plasma total homocysteine (tHcy) levels, particularly among chronic renal disease (CRD) patients with a normal range serum creatinine. Studies of this potential relationship have been limited by failure to assess true GFR, failure to assess proteinuria in a quantitative manner, or arbitrary restriction of the range of proteinuria examined. We examined the potential independent relationship between plasma tHcy levels and a wide range of quantitatively determined proteinuria (i.e., 0.000-8.340 g/day), among 109 CRD patients with a normal range serum creatinine (range; 0.8-1.5 mg/dl; median=1.2 mg/dl). Glomerular filtration rate (GFR) was directly assessed by iohexol clearance, and plasma status of folate, pyridoxal 5'-phosphate, and B12, along with serum albumin, were also determined. Linear modeling with ANCOVA revealed that proteinuria was not independently associated with tHcy levels (partial R=0.127; P=0.201), after adjustment for potential confounding by GFR (partial R=0.408; P<0.001), age, sex, plasma B-vitamin status, and serum albumin. Moreover, descending across quartiles (Q) [from Q4 to Q1] of GFR, ANCOVA-adjusted (i.e., for age, sex, and folate status) geometric mean tHcy levels (micromol/l) were significantly increased: tHcy Q4 GFR=9.6; tHcy Q3 GFR=10.5; tHcy Q2 GFR=11.9; tHcy Q4 GFR=14.5; P<0.001 for overall Q difference. We conclude that across a broad spectrum of quantitatively determined proteinuria, after adjustment for true GFR, in particular, there is no independent relationship between proteinuria and tHcy levels among CRD patients with a normal range serum creatinine.
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Affiliation(s)
- A G Bostom
- Division of General Internal Medicine, Memorial Hospital of Rhode Island, 111 Brewster Street, Pawtucket, RI, USA.
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Abstract
Homocysteine (Hcy) is an intermediate of methionine metabolism that, at elevated levels, is an independent risk factor for vascular disease and atherothrombosis. Patients with renal disease, who exhibit unusually high rates of cardiovascular morbidity and death, tend to be hyperhomocysteinemic, particularly as renal function declines. This observation and the inverse relationship between Hcy levels and GFR implicate the kidney as an important participant in Hcy handling. The normal kidney plays a major role in plasma amino acid clearance and metabolism. The existence in the kidney of specific Hcy uptake mechanisms and Hcy-metabolizing enzymes suggests that this role extends to Hcy. Dietary protein intake may affect renal Hcy handling and should be considered when measuring Hcy plasma flux and renal clearance. The underlying cause of hyperhomocysteinemia in renal disease is not entirely understood but seems to involve reduced clearance of plasma Hcy. This reduction may be attributable to defective renal clearance and/or extrarenal clearance and metabolism, the latter possibly resulting from retained uremic inhibitory substances. Although the currently available evidence is not conclusive, it seems more likely that a reduction in renal Hcy clearance and metabolism is the cause of the hyperhomocysteinemic state. Efforts to resolve this important issue will advance the search for effective Hcy-lowering therapies in patients with renal disease.
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Affiliation(s)
- Allon N Friedman
- Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Division of Nephrology, Tufts University-New England Medical Center, Boston, Massachusetts
| | - Andrew G Bostom
- Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
- Division of General Internal Medicine, Memorial Hospital of Rhode Island, Pawtucket, Rhode Island
| | - Jacob Selhub
- Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
| | - Andrew S Levey
- Division of Nephrology, Tufts University-New England Medical Center, Boston, Massachusetts
| | - Irwin H Rosenberg
- Vitamin Metabolism and Aging, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts
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Abstract
Mild to moderate hyperhomocysteinemia (Hhcy) is observed in more than 90% of patients with end-stage renal disease (ESRD) undergoing maintenance dialysis and approximately 60% to 70% of chronic stable renal transplant recipients. The reported association between Hhcy and the development of arteriosclerotic cardiovascular disease may account, in part, for the disproportionate risk for cardiovascular morbidity and mortality in patients with chronic renal disease. Treatment with the recommended daily allowances of folic acid and vitamins B(6) and B(12), which consistently normalizes total homocysteine (tHcy) levels in the general population free of chronic renal disease, rarely results in the normalization of tHcy levels in patients with ESRD. A large number of investigations now have shown that even grossly supraphysiological doses of folic acid and vitamins B(6) and B(12) fail to normalize tHcy levels in more than 90% of dialysis-dependent patients with ESRD with baseline Hhcy. Conversely, such treatment consistently normalizes tHcy levels among hyperhomocysteinemic chronic stable renal transplant recipients or patients with mild to moderate renal insufficiency. A randomized, placebo-controlled, tHcy-lowering intervention trial involving approximately 4,000 chronic stable US renal transplant recipients (RO1 DK56486 01A2) will soon be underway to formally address the tenable hypothesis that tHcy-lowering treatment may reduce the risk for arteriosclerotic outcomes. Data from this trial should be applicable to patients with chronic renal insufficiency in general.
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Affiliation(s)
- D Shemin
- Division of Renal Diseases, Rhode Island Hospital, Brown University School of Medicine, Providence, RI, USA.
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Liaugaudas G, Jacques PF, Selhub J, Rosenberg IH, Bostom AG. Renal insufficiency, vitamin B(12) status, and population attributable risk for mild hyperhomocysteinemia among coronary artery disease patients in the era of folic acid-fortified cereal grain flour. Arterioscler Thromb Vasc Biol 2001; 21:849-51. [PMID: 11348885 DOI: 10.1161/01.atv.21.5.849] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fortification of enriched cereal grain flour products with folic acid has drastically reduced the prevalence of deficient plasma folate status, a major determinant of plasma total homocysteine (tHcy) levels. We hypothesized that even more liberally defined "suboptimal" plasma folate status might no longer contribute importantly to the population attributable risk (PAR) for mild hyperhomocysteinemia, a putative atherothrombotic risk factor. We determined fasting plasma tHcy, folate, vitamin B(12), and pyridoxal 5'-phosphate levels, along with serum creatinine and albumin levels, in 267 consecutive patients (aged 61+/-9 [mean+/-SD] years, 76.4% men and 26.6% women) with stable coronary artery disease (CAD) who were nonusers of vitamin supplements or had abstained from supplement use for at least 6 weeks before examination. Subjects were evaluated a minimum of 3 months after the implementation of flour fortification was largely completed. Relative risk estimates for the calculation of PAR were derived from a multivariable-adjusted logistic regression model with >/=12 micromol/L tHcy as the dependent variable and with age, sex, pyridoxal 5'-phosphate (continuous), albumin (continuous), <5 ng/mL folate, <250 pg/mL vitamin B(12), and >/=1.3 mg/dL creatinine as the independent variables. The prevalence of >/=12 micromol/L plasma tHcy was 11.2% (30 of 267 patients). PAR estimates (percentage) for >/=12 micromol/L tHcy were as follows: <5 ng/mL folate (<1%), <250 pg/mL vitamin B(12) (24.5%), and >/=1.3 mg/dL creatinine (37.5%). In the era of folic acid-fortified cereal grain flour, renal insufficiency and suboptimal vitamin B(12) status (but not folate status) contribute importantly to the PAR for mild hyperhomocysteinemia among patients with stable CAD.
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Affiliation(s)
- G Liaugaudas
- Division of General Internal Medicine, Memorial Hospital of Rhode Island, Providence, USA
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Bostom AG, Selhub J, Jacques PF, Rosenberg IH. Power Shortage: clinical trials testing the "homocysteine hypothesis" against a background of folic acid-fortified cereal grain flour. Ann Intern Med 2001; 135:133-7. [PMID: 11453713 DOI: 10.7326/0003-4819-135-2-200107170-00014] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Large randomized, controlled trials of total homocysteine-lowering therapy for the potential reduction of cardiovascular disease outcomes are ongoing in the United States and Canada. These trials are the Vitamin Intervention for Stroke Prevention (VISP) trial, the Women's Antioxidant Cardiovascular Disease Study (WACS), and the Heart Outcomes Prevention Evaluation (HOPE-2). However, the dramatic effect of policies mandating fortification of cereal grain flour products with folic acid may reduce the statistical power of these trials. All three trials assume that the active treatment groups will achieve the same mean effects of total homocysteine-lowering therapy as those reported in the absence of folic acid-fortified cereal grain flour. This paper examines this assumption using data from studies of total homocysteine-lowering therapy in U.S. and Canadian patients with cardiovascular disease who were exposed to products made with folic acid-fortified cereal grain flour. These data showed that the VISP trial, HOPE-2, and WACS will probably achieve only approximately 20% to 25% of the projected treatment effects of mean total homocysteine-lowering therapy (1.0 to 1.5 micromol/L vs. 4.0 to 6.0 micromol/L). As a result, all three trials will be substantially underpowered to test the specific hypotheses of total homocysteine-lowering therapy identified a priori. In contrast, renal transplant recipients have a persistent excess prevalence of hyperhomocysteinemia in the era of fortification but remain very responsive to supraphysiologic doses of folic acid-based supplementation (mean reduction in total homocysteine level, 5.0 to 6.0 micromol/L). Therefore, unlike other populations with normal renal function that are at high risk for cardiovascular disease but are profoundly affected by fortification efforts, renal transplant recipients continue to merit serious consideration for a controlled trial of the "homocysteine hypothesis."
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Affiliation(s)
- A G Bostom
- Division of Renal Diseases, Rhode Island Hospital, 593 Eddy Street, Providence, RI 02903, USA.
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Selhub J, Jacques PF, Bostom AG, Wilson PW, Rosenberg IH. Relationship between plasma homocysteine and vitamin status in the Framingham study population. Impact of folic acid fortification. Public Health Rev 2001; 28:117-45. [PMID: 11411265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
Recent studies have demonstrated associations between occlusive vascular disease and hyperhomocysteinemia of both genetic and nutritional origin. In the present study we analyzed plasma samples from the 20th biannual examination of the Framingham Heart Study cohort to determine distribution of plasma homocysteine concentrations with emphasis on relationships to vitamins that serve as coenzymes in homocysteine metabolism and to prevalence of carotid artery stenosis. Results showed that homocysteine exhibited strong inverse association with plasma folate and weaker associations with plasma vitamin B12 and pyridoxal-5'-phosphate. We saw similar inverse associations between homocysteine and intakes of folate and vitamin B6, but not vitamin B12. Prevalence of high homocysteine (> 14 mumol/L) was 29.3% in this cohort, and was greatest among subjects with low folate status. Inadequate plasma concentrations of one or more B vitamins appear to contribute to 67% of the cases of high homocysteine. Prevalence of stenosis > or = 25% was 43% in men and 34% in women, with an odds ratio of 2.0 for individuals in the highest homocysteine quartile (> or = 14.4 mumol/L) compared with those in the lowest quartile (< or = 9.1 mumol/L), after adjustment for sex, age, HDL cholesterol, systolic blood pressure, and cigarette smoking (Ptrend < 0.001). Plasma concentrations of folate and pyridoxal-5'-phosphate and folate intake were inversely associated with extracranial carotid stenosis after adjustment for age, sex, and other risk factors. Studies using samples from the Framingham Study Offspring Cohort have shown that the US-mandated folic acid fortification of flour and cereal grain products resulted in an increase in the mean folate concentrations from 4.8 to 10.0 ng/mL (P < 0.001) and prevalence of low folate (< 3 ng/mL) decreased from 22.0 to 1.7% (P < 0.001) between the baseline and follow-up visits. Mean homocysteine concentration decreased from 10.1 to 9.4 microM (P < 0.001), and prevalence of high homocysteine (> 13 mumol/L) decreased from 18.7 to 9.8% (P < 0.001) between study visits. There were no statistically significant changes in the control group for folate or homocysteine between examinations. These data indicate a high prevalence of hyperhomocysteinemia in the Framingham Study population, the majority of which can be attributed to vitamin status and that this hyperhomocysteinemia is clinically relevant because of its association with increased risk of occlusive extracranial carotid stenosis. Insufficient levels of folate, and to a lesser extent vitamin B6, appear to predict part of this elevated risk through their role in homocysteine metabolism. These studies also indicate that the recently-implemented fortification of grain and cereal products with folic acid resulted in a substantial decline in plasma homocysteine. The impact of fortification on the US population is likely to be similar; however it awaits the next survey for further confirmation.
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Affiliation(s)
- J Selhub
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA.
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