Addition of the multidimensional prognostic index to the estimated glomerular filtration rate improves prediction of long-term all-cause mortality in older patients with chronic kidney disease

Current prognostic scores of chronic kidney disease (CKD) are not accurate in older patients. The aim of this study was to evaluate the prognostic accuracy of the Multidimensional Prognostic Index (MPI) in comparison with and in addition to the estimated glomerular filtration rate (eGFR) to predict long-term all-cause mortality in hospitalized older patients with CKD. In a prospective cohort study with a mean follow-up of 2 years, we calculated eGFR according to the Modification of Diet in Renal Disease study and collected information on functional, cognitive, nutritional, co-morbidities, drug use, and co-habitation status to calculate the MPI on 1,198 patients aged ≥65 years with a diagnosis of CKD from an hospital-based sample. The all-cause mortality incidence rate for 100 person-years was 18.3 (men 22.7 vs. women 15.3, p<0.0001). Adding the MPI to the eGFR model significantly improved all-cause mortality prediction accuracy: The C-index increased from 0.579 to 0.648 (p<0.0001), with correct reclassification of 25.9% of patients (Net Reclassification Improvement [NRI], 0.259, p<0.0001; Integrated Discrimination Improvement [IDI], 3.8%, p<0.0001). The correct reclassification was higher in patients who did not die (259/741 patients, reclassification rate=34.9%) than in patients who died (62/457 patients, reclassification rate=13.6%). Conversely, adding the eGFR to the MPI model seems to improve prediction accuracy less consistently. In fact, the C-index increased, but not significantly (from 0.639 to 0.648, p=0.444), with correct reclassification of 5.8% of patients (NRI, 0.058, p=0.012; IDI, 0.009, p=0.001), suggesting a small, although significant improvement. Adding MPI information to the eGFR markedly improved the prediction of 2-year all-cause mortality in older patients with CKD. A multidimensional evaluation for all-cause mortality risk prediction should be considered in older patients with CKD.

A simple prediction score for kidney disease in the Korean population

AIM

Screening algorithms for chronic kidney disease have been developed and validated in American populations. Given the worldwide burden of kidney disease, developing algorithms for populations outside the USA is needed.

METHODS

Using simple, non-invasive questions, we developed a prediction model for chronic kidney disease from national population samples in Korea. The Korean National Health and Nutrition Examination Survey (n = 6565) was used for model development while validation was performed in two independent population samples, internal (n = 2921) and external datasets (n = 8166). Chronic kidney disease was defined as glomerular filtration rate < 60 mL/min per 1.73 m(2).

RESULTS

Seven factors - age, female gender, anaemia, hypertension, diabetes mellitus, cardiovascular disease and proteinuria - were significantly associated with prevalent chronic kidney disease. Integer scores were assigned to variables based on the magnitude of associations: 2 for age 50-59 years, 3 for age 60-69 years and 4 for age 70 years or older, and 1 for female gender, anaemia, hypertension, diabetes, proteinuria and cardiovascular dis ase. Based on the Youden index, a value of 4 or greater defined a high risk population with sensitivity 89%, specificity 71%, and positive predictive value 19%, and negative predictive value 99%. The area under the curve was 0.83 for the development set, and 0.87 and 0.78 in the two validation datasets.

CONCLUSION

This prediction algorithm, weighted towards common non-invasive variables, had good performance characteristics in an Asian population, and provides new evidence of the similarity of the algorithms for Western and Eastern populations.

Renal safety of tenofovir containing antiretroviral regimen in a Singapore cohort

BACKGROUND

Tenofovirdisoproxilfumarate (TDF) is a nucleotide analogue widely recommended in international HIV treatment guidelines. The association of TDF and renal dysfunction has remained an area of interest.

FINDINGS

We conducted a retrospective review of all patients on TDF from July 2007 to December 2009 in our institution and evaluated their renal function. Absolute change of creatinine clearance (CLCr) using Cockroft-Gault equation from baseline was calculated at 6, 12, 18 and 24 months. Overall, 226 patients were included in the study. Ninety percent were male. The median age was 46 yrs old (23-82), median weight was 60 kg (IQR 53.75-68), median CD4 count was 127 cells/mm3 (IQR 38-258) and median CLCr 82.7 mL/min (IQR 71.4-101.7) on initiation of TDF. The median decline of CLCr from baseline was -3.9 ml/min (IQR -12.3 to 7.6), and -3.6 ml/min (IQR -12.4 to 6.7) at 12 (n = 102), 24 months (n = 75) respectively. Eighteen of 226 patients had a decline in renal function to </=50 ml/min. Majority of which had an improvement of CLCr on follow up. Only 80% of patients ever received monitoring of renal function.

CONCLUSION

While we noted renal toxicity to be rare and transient among our cohort receiving TDF as part of their ARV regimen, these results reflect the short term renal effects of TDF given that ARV treatment is lifelong. Given that laboratory monitoring may be difficult to implement in many situations, future prospective studies looking into an evidence based algorithm for less frequent renal function monitoring than current guideline recommendations may be helpful.

Predicting progression of IgA nephropathy: new clinical progression risk score

IgA nephropathy (IgAN) is a common cause of end-stage renal disease (ESRD) in Asia. In this study, based on a large cohort of Chinese patients with IgAN, we aim to identify independent predictive factors associated with disease progression to ESRD. We collected retrospective clinical data and renal outcomes on 619 biopsy-diagnosed IgAN patients with a mean follow-up time of 41.3 months. In total, 67 individuals reached the study endpoint defined by occurrence of ESRD necessitating renal replacement therapy. In the fully adjusted Cox proportional hazards model, there were four baseline variables with a significant independent effect on the risk of ESRD. These included: eGFR [HR = 0.96(0.95-0.97)], serum albumin [HR = 0.47(0.32-0.68)], hemoglobin [HR = 0.79(0.72-0.88)], and SBP [HR = 1.02(1.00-1.03)]. Based on these observations, we developed a 4-variable equation of a clinical risk score for disease progression. Our risk score explained nearly 22% of the total variance in the primary outcome. Survival ROC curves revealed that the risk score provided improved prediction of ESRD at 24th, 60th and 120th month of follow-up compared to the three previously proposed risk scores. In summary, our data indicate that IgAN patients with higher systolic blood pressure, lower eGFR, hemoglobin, and albumin levels at baseline are at a greatest risk of progression to ESRD. The new progression risk score calculated based on these four baseline variables offers a simple clinical tool for risk stratification.

One-year change in kidney function is associated with an increased mortality risk

BACKGROUND

Serum creatinine is routinely measured to estimate glomerular filtration rate (GFR). Long-term cohort studies report that death is a likelier outcome than progression to kidney failure. However, it is unclear how short-term changes in estimated GFR (eGFR) over a 1-year period relate to subsequent mortality risk.

METHODS

Using a provincial laboratory registry from Alberta, Canada, we identified 598,397 adults who had ≥2 outpatient eGFR measurements at least 6 months apart during a 1-year accrual period. Change in kidney function was categorized by both changes in eGFR category and percent change ≥25% into 5 groups: certain drop, uncertain drop, stable (no change in CKD category), uncertain rise, and certain rise. Cox proportional hazards models, adjusting for baseline covariates, kidney function, and proteinuria were used to estimate the risk of all-cause mortality associated with each group change in kidney function in reference to stable kidney function.

RESULTS

Among the study participants, 447,570 (74.8%) had stable kidney function, 19,591 (3.3%) had a certain drop, and 22,171 (3.7%) had a certain rise in kidney function. Participants with change in kidney function (both drop and rise) were older, more likely to be female, and had a higher prevalence of comorbidities in comparison to those with stable kidney function. There were 51,473 (8.6%) deaths during a median follow-up of 3.5 years. Compared to participants with stable kidney function, those with a certain drop had an almost twofold increased mortality risk (hazard ratio 1.89, 95% CI 1.83-1.95) adjusted for baseline eGFR, proteinuria, and covariates. Participants with a certain rise (3.7%) in kidney function also experienced an increased mortality risk (hazard ratio 1.51, 95% CI 1.46-1.56) compared to those with stable kidney function. Risk of death was similarly increased with adjustment for eGFR at the last visit.

CONCLUSION

Change in kidney function of ≥25% in any direction over a 1-year period is associated with a substantially increased risk of mortality.

C5a and its receptors in human anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis

Introduction

The complement system is crucial for the development of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). In particular, C5a plays a central role. In this study, plasma and urinary levels of C5a as well as renal C5a receptors (CD88 and C5L2) expression were investigated in patients with AAV.

Methods

Twenty-four patients with AAV in the active phase, 19 patients with AAV in the remission phase, and 20 patients with lupus nephritis (LN) were included. Plasma and urinary levels of C5a were measured with enzyme-linked immunosorbent assay (ELISA). The staining of CD88 and C5L2 in renal specimens was detected with immunohistochemistry.

Results

The level of plasma C5a was significantly higher in patients with AAV in the active phase than that in patients in remission, that in patients with LN, and that in normal controls. The urinary C5a level was significantly higher in patients with AAV in the active phase than that in patients in remission and that in normal controls, but not significantly different between patients with active AAV and patients with LN. The mean optical density of CD88 staining in the tubulointerstitium was significantly lower in AAV patients than that in normal controls (0.0052 ± 0.0011 versus 0.029 ± 0.0042; P = 0.005). The mean optical density of C5L2 in glomeruli was significantly higher in AAV patients than that in normal controls (0.013 ± 0.0027 versus 0.0032 ± 0.0006; P < 0.001). The mean optical density of CD88 staining closely correlated with the initial eGFR (r = 0.835; P < 0.001) in AAV patients. Double-labeling immunofluorescence assay suggested that CD88 did not express on neutrophils, monocytes, or macrophages, but C5L2 expressed on neutrophils (or monocytes) and macrophages.

Conclusion

The elevated plasma and urinary C5a levels indicated complement activation in human AAV. The level of renal CD88 expression could reflect the disease severity of ANCA-associated glomerulonephritis. CD88 expression was downregulated, and C5L2 was upregulated in ANCA-associated glomerulonephritis.

Estimated glomerular filtration rate from serum cystatin C: significant differences among several equations results

OBJECTIVES

Several equations for the estimation of glomerular filtration rate (GFR) from serum cystatin C have been reported. We compared the results obtained using these equations to test the homogeneity of their results as well as their usefulness in clinical practice.

DESIGN AND METHODS

Seven hundred and twenty-seven outpatients were studied. Of these, 439 were male and 288 were female, and their mean age was 60.8 ± 24.1 years. GFR was estimated from serum creatinine using the abbreviated Modification of Diet in Renal Disease (MDRD-4) equation. GFR was estimated from serum cystatin C levels using five different equations.

RESULTS

The simplest (100/cystatin C) formula rendered the highest estimated GFR and the Hoek's equation rendered the lowest GFR, even significantly lower than the MDRD-4 equation (p < 0.001, Student's t-test). From the simplest formula to the Hoek equation the mean difference calculated was 25.1 ± 8.7 mL/min (p < 0.001, Student's t-test). No differences by gender were found among the results of different equations. All cystatin C-derived equations reduced the number of patients diagnosed of chronic renal failure when compared with MDRD-4 formula. No patient with normal renal function was shifted to the renal disease group.

CONCLUSIONS

A higher value could be expected when GFR is estimated from cystatin C. Nevertheless, vast differences were found in the results when tested using several equations. Physicians should be aware of this problem to avoid a wrong clinical diagnosis of renal function.

Estimating GFR among participants in the Chronic Renal Insufficiency Cohort (CRIC) Study

BACKGROUND

Glomerular filtration rate (GFR) is considered the best measure of kidney function, but repeated assessment is not feasible in most research studies.

STUDY DESIGN

Cross-sectional study of 1,433 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study (ie, the GFR subcohort) to derive an internal GFR estimating equation using a split-sample approach.

SETTING & PARTICIPANTS

Adults from 7 US metropolitan areas with mild to moderate chronic kidney disease; 48% had diabetes and 37% were black.

INDEX TEST

CRIC GFR estimating equation.

REFERENCE TEST OR OUTCOME

Urinary (125)I-iothalamate clearance testing (measured GFR [mGFR]).

OTHER MEASUREMENTS

Laboratory measures, including serum creatinine and cystatin C, and anthropometrics.

RESULTS

In the validation data set, the model that included serum creatinine level, serum cystatin C level, age, sex, and race was the most parsimonious and similarly predictive of mGFR compared with a model additionally including bioelectrical impedance analysis phase angle, CRIC clinical center, and 24-hour urinary creatinine excretion. Specifically, root mean square errors for the separate models were 0.207 versus 0.202, respectively. Performance of the CRIC GFR estimating equation was most accurate for the subgroups of younger participants, men, nonblacks, non-Hispanics, those without diabetes, those with body mass index <30 kg/m(2), those with higher 24-hour urine creatinine excretion, those with lower high-sensitivity C-reactive protein levels, and those with higher mGFRs.

LIMITATIONS

Urinary clearance of (125)I-iothalamate is an imperfect measure of true GFR; cystatin C level is not standardized to certified reference material; lack of external validation; small sample sizes limit analyses of subgroup-specific predictors.

CONCLUSIONS

The CRIC GFR estimating equation predicts mGFR accurately in the CRIC cohort using serum creatinine and cystatin C levels, age, sex, and race. Its performance was best in younger and healthier participants.

The effectiveness of intensive nursing care on seasonal variation of blood pressure in patients on peritoneal dialysis

AIM

  This article is a report of a study to reduce the seasonal variation of blood pressure in patients on peritoneal dialysis through an intensive programme of nursing care.

BACKGROUND

  The seasonal variation of blood pressure is a common phenomenon in patients on maintenance dialysis. Whether or not this variation can be reduced through a given intervention is unknown.

METHODS

  The programme of intensive nursing care including education on volume control, home blood pressure monitoring and intensified antihypertensive treatment, was implemented from December 2006. The blood pressure, fluid and sodium removal and defined daily doses of antihypertensive agents were measured at 1-monthly intervals and averagely quarterly for seasonal values for spring, summer, autumn and winter, respectively, before (December 2005-November 2006) and after intervention (December 2006-November 2007).

FINDINGS

  A total of 76 clinically stable patients on peritoneal dialysis were enrolled and finally analysed. The mean age was 60·6 years, and dialysis duration was 23·2 months. Before intervention, there were important seasonal variations in systolic and diastolic blood pressure. After intensive nursing care was implemented, the seasonal variation of systolic blood pressure disappeared. The diastolic blood pressure still represented a season pattern, but the discrepancy between winter and summer decreased. There were no seasonal patterns of total fluid and sodium removal before and after intervention.

CONCLUSIONS

  Intensive nursing care reduced the seasonal variation of blood pressure in patients on peritoneal dialysis. These data provided an evidence for implementing nurse-centred interventions in this population.

Predictive performance of eGFR equations in South Africans of African and Indian ancestry compared with ⁹⁹mTc-DTPA imaging

BACKGROUND

South African guidelines for early detection and management of chronic kidney disease (CKD) recommend using the Cockcroft-Gault (CG) or Modification of Diet in Renal Disease (MDRD) equations for calculating estimated glomerular filtration rate (eGFR) with the correction factor, 1.212, included for MDRD-eGFR in black patients. We compared eGFR against technetium-99m-diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) imaging.

METHODS

Using clinical records, we retrospectively recorded demographic, clinical, and laboratory data as well as (99m)Tc-DTPA-measured GFR (mGFR) results obtained from routine visits. Data from 148 patients of African (n = 91) and Indian (n = 57) ancestry were analyzed.

RESULTS

Median (IQR) mGFR was 38.5 (44) ml/min/1.73 m(2), with no statistical difference between African and Indian patients (P = 0. 573). In African patients with stage 3 CKD, MDRD-eGFR (unadjusted for black ethnicity) overestimated mGFR by 5.3% [2.0 (16.0) ml/min/1.73 m(2)] compared to CG-eGFR and MDRD-eGFR (corrected for black ethnicity) that overestimated mGFR by 17.7% [6.0 (15.0) ml/min/1.73 m(2)] and 17.1% [6.0 (17.5) ml/min/1.73 m(2)], respectively. In stage 1-2, CKD eGFR overestimated mGFR by 52.5, 38.0, and 19.3% for CG, MDRD (ethnicity-corrected), and MDRD (without correction), respectively. In Indian stage 3 CKD patients, MDRD-eGFR underestimated mGFR by 35.6% [-21.0 (6.5) ml/min/1.73 m(2)] and CG-eGFR by 4.4% [-2.0 (27.0) ml/min/1.73 m(2)], while in stage 1-2 CKD, CG-eGFR and MDRD-eGFR overestimated mGFR by 13.8 and 6.3%, respectively.

CONCLUSION

MDRD-eGFR calculated without the African-American correction factor improved GFR prediction in African CKD patients and using the MDRD correction factor of 1.0 in Indian patients as in Caucasians may be inappropriate.

Association between nonalcoholic fatty liver disease (NAFLD) and osteoporotic fracture in middle-aged and elderly Chinese

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) has been considered as a hepatic manifestation of the metabolic syndrome and is associated with various metabolic abnormalities, which may link to an increased risk of osteoporotic fracture. However, epidemiological studies investigating the association between NAFLD and osteoporotic fracture were not available.

OBJECTIVE

The objective of the study was to determine whether NAFLD associates with osteoporotic fracture.

DESIGN, SETTING, AND PARTICIPANTS

This was a cross-sectional study of 7797 Chinese adults aged 40 yr or older in the Jiading District, Shanghai, China.

MAIN OUTCOME MEASURES

A questionnaire, anthropometric measurements, laboratory tests, and a hepatic ultrasonic examination were conducted. NAFLD was diagnosed by hepatic ultrasound after the exclusion of alcohol abuse and other liver diseases. A history of fractures was collected with an interviewer-assisted questionnaire. Osteoporotic fractures were defined as fractures that occurred due to low-trauma in 2 yr prior to the study.

RESULTS

Among men, the prevalence of osteoporotic fractures was significantly higher in those with NAFLD (3.6 vs. 1.7%, P = 0.003); however, no difference was found in women (3.4 vs. 2.6%, P = 0.14). The presence of NAFLD was significantly associated with increased odds of osteoporotic fracture among men (odds ratio 2.53; 95% confidence interval 1.26-5.07; P = 0.009) after controlling for potential confounders. The significant associations were not detected in women.

CONCLUSIONS

The presence of NAFLD was significantly associated with a recent history of osteoporotic fracture in middle-aged and elderly Chinese men.

Association of glomerular filtration rate with high-sensitivity cardiac troponin T in a community-based population study in Beijing

BACKGROUND

Reduced renal function is an independent risk factor for cardiovascular disease mortality, and persistently elevated cardiac troponin T (cTnT) is frequently observed in patients with end-stage renal disease. In the general population the relationship between renal function and cTnT levels may not be clear because of the low sensitivity of the assay. In this study, we investigated the level of cTnT using a highly sensitive assay (hs-cTnT) and evaluated the association of estimated glomerular filtration rate (eGFR) with detectable hs-cTnT levels in a community-based population.

METHODS

The serum hs-cTnT levels were measured in 1365 community dwelling population aged ≥45 years in Beijing, China. eGFR was determined by the Chinese modifying modification of diet in renal disease (C-MDRD) equation.

RESULTS

With the highly sensitive assay, cTnT levels were detectable (≥3pg/mL) in 744 subjects (54.5%). The result showed that eGFR was associated with Log hs-cTnT (r = -0.14, P<0.001). After adjustment for the high predicted Framingham Coronary Heart Disease (CHD) risk (10-year risk >20%) and other prognostic indicators, moderate to severe reduced eGFR was independently associated with detectable hs-cTnT, whereas normal to mildly reduced eGFR was not independently associated with detectable hs-cTnT. In addition, after adjustment for other risk factors, the high predicted Framingham CHD risk was associated with detectable hs-cTnT in the subjects with different quartile levels of eGFR.

CONCLUSION

The levels of hs-cTnT are detectable in a community-based Chinese population and low eGFR is associated with detectable hs-cTnT. Moreover, eGFR and high predicted Framingham CHD risk are associated with detectable hs-cTnT in subjects with moderate-to-severe reduced renal function.

Risk factors of cardiovascular disease among children with chronic kidney disease in Gaza strip

Background:

Chronic kidney disease (CKD) is increasingly recognized as a global public health problem. Cardiovascular disease (CVD) is a major cause of mortality in patients with mild-to-moderate CKD and end-stage renal disease. There is accumulating evidence that the increase in CVD burden is present in CKD patients prior to dialysis, due both to conventional risk factors and kidney-specific disease. Detection and initiation of treatment for CVD risk factors at early stages of CKD should be effective in reducing CVD events before as well as after the onset of kidney failure.

Materials and Methods:

The study sample consisted of a total of 112 subjects aged ≤12 years: 60 CKD patients and 52 healthy control individuals. All subjects were investigated for a group of CVD risk factors such as: Hypertension, diabetes, dyslipidemia, physical inactivity, body mass index (BMI), family history of CVD, hypoalbuminemia, albuminuria, anemia, Ca x P product, and inflammation in terms of C-reactive protein (CRP).

Results:

Patients (40 males and 20 females) were categorized into four CKD stages (2, 3, 4, and 5) where, Stage 4 had the highest frequency, followed by Stages 3, 5 and 2. Evaluation of the patients indicated that they were shorter, had lower weight and had higher systolic and diastolic blood pressure as compared with control subjects. Frequency of physical inactivity among patients was two-fold higher than controls (50% vs. 25%). The patients showed significantly higher levels of cholesterol (163.6±39.8 vs. 141.8±24.2 mg/dL, P<0.0001), triglycerides (145.5±67.1 vs. 82.9±39.8 mg/dL, P<0.0001), low-density lipoprotein (92.6±31.9 vs. 72.5±19 mg/dL, P<</i>0.0001) and albumin/creatinine ratio (1792±3183 vs. 11.1±6.6 mg/g, P<0.0001). Moreover, the patients had lower levels of high-density lipoprotein (41.9±11.0 vs. 52.7±11.7 mg/dL, P<0.0001), hemoglobin (9.8±1.4 vs. 11.9±0.8 g/dL, P<0.0001) and albumin (4.6±0.6 vs. 4.8±0.2 g/dL, P=0.012). The CRP showed higher occurrence among patients (40% were positive for CRP). Calcium and phosphorus evaluation showed significantly lower calcium and higher phosphorus among patients. However, the difference in Ca X P product was not statistically significant.

Conclusions:

The study indicates that many of the CVD risk factors are associated with the different stages of CKD in children patients prior to dialysis, and that some of these factors are exacerbated as CKD progresses.

Advanced oxidation protein products as prognostic biomarkers for recovery from acute kidney injury after coronary artery bypass grafting

Recovery from acute kidney injury (AKI) is related to long-term prognosis. This study, involving 56 patients with AKI and 56 controls from a prospective cohort undergoing coronary artery bypass grafting (CABG), investigated the prognostic performance of serum levels of advanced oxidation protein products (AOPPs) for predicting non-recovered AKI and non-completely recovered AKI. AOPP levels increased significantly 7 days after surgery in patients with non-recovered or non-completely recovered AKI. Increased AOPP levels were associated with both types of poor recovery from AKI. Results from receiver-operating characteristic (ROC) curves demonstrated that AOPP levels had good prognostic value for predicting non-recovered and non-completely recovered AKI.

Assessment of the CKD-EPI equation to estimate glomerular filtration rate in adults from a Chinese CKD population

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was introduced to estimate glomerular filtration rate (GFR) in chronic kidney disease (CKD) patients based on serum creatinine. The CKD-EPI equation shows better accuracy compared with the current gold standard equation, the Modification of Diet in Renal Disease (MDRD) equation, but it has not been externally validated in Chinese patients. This study compared the CKD-EPI equation with the original MDRD equation and two Chinese MDRD-based equations for estimating GFR in 200 Chinese CKD patients. The (99m)Tc-diethylenetriamine penta-acetate ((99m)Tc-DTPA) method was used to determine actual GFR. The CKD-EPI equation produced GFR estimates that were more consistent with the (99m)Tc-DTPA GFR than did the MDRD equations. The precision and accuracy of the CKD-EPI equation were significantly higher than those of the MDRD equations. In conclusion, the CKD-EPI equation was superior to the existing MDRD equations in terms of estimating GFR and we recommend its clinical use in Chinese CKD patients.

A pilot trial assessing urinary gene expression profiling with an mRNA array for diabetic nephropathy

Background

The initiation and progression of diabetic nephropathy (DN) is complex. Quantification of mRNA expression in urinary sediment has emerged as a novel strategy for studying renal diseases. Considering the numerous molecules involved in DN development, a high-throughput platform with parallel detection of multiple mRNAs is needed. In this study, we constructed a self-assembling mRNA array to analyze urinary mRNAs in DN patients with aims to reveal its potential in searching novel biomarkers.

Methods

mRNA array containing 88 genes were fabricated and its performance was evaluated. A pilot study with 9 subjects including 6 DN patients and 3 normal controls were studied with the array. DN patients were assigned into two groups according to their estimate glomerular rate (eGFR): DNI group (eGFR>60 ml/min/1.73 m², n = 3) and DNII group (eGFR<60 ml/min/1.73 m², n = 3). Urinary cell pellet was collected from each study participant. Relative abundance of these target mRNAs from urinary pellet was quantified with the array.

Results

The array we fabricated displayed high sensitivity and specificity. Moreover, the Cts of Positive PCR Controls in our experiments were 24±0.5 which indicated high repeatability of the array. A total of 29 mRNAs were significantly increased in DN patients compared with controls (p<0.05). Among these genes, α-actinin4, CDH2, ACE, FAT1, synaptopodin, COL4α, twist, NOTCH3 mRNA expression were 15-fold higher than those in normal controls. In contrast, urinary TIMP-1 mRNA was significantly decreased in DN patients (p<0.05). It was shown that CTGF, MCP-1, PAI-1, ACE, CDH1, CDH2 mRNA varied significantly among the 3 study groups, and their mRNA levels increased with DN progression (p<0.05).

Conclusion

Our pilot study demonstrated that mRNA array might serve as a high-throughput and sensitive tool for detecting mRNA expression in urinary sediment. Thus, this primary study indicated that mRNA array probably could be a useful tool for searching new biomarkers for DN.

Prevalence and risk factors of chronic kidney disease in first-degree relatives of chronic kidney disease patients in Southern China

AIM

The aim of this study was to estimate the prevalence and risk factors of chronic kidney disease (CKD) in first-degree relatives (FDRs) of CKD patients.

METHODS

A cross-section study of first-degree relatives of CKD patients was conducted between November 2007 and March 2009 in southern China. A total of 1187 first-degree relatives (494 male and 693 female; mean age 41.26 years) of 419 CKD patients (194 male and 225 female; mean age 32.10 years) were reviewed and tested for haematuria, albuminuria and reduced glomerular filtration rate. CKD risk factors, including age, gender, body mass index, hypertension and the causes of index case were also investigated. CKD was diagnosed according to the criteria of the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative.

RESULTS

The prevalence of CKD in first-degree relatives of CKD patients was 29.7% (95% confidence interval [CI]: 27.1%-32.2%). After adjusting for all the potential confounders, older age, female gender, hypertension, hyperglycaemia, hyperuricaemia, hypertriglyceridemic, low level of high density lipoproteins, increased body mass index and nephrotoxic medications were independently associated with increased risk of CKD. Furthermore, relatives of index cases with chronic glomerulonephritis were at higher risk haematuria (ORs = 2.12, 95% CI: 1.45-3.10) compared with relatives of index cases with other kinds of renal diseases.

CONCLUSION

The first-degree relatives of CKD patients are at high risk of CKD, especially those relatives of CKD patients with chronic glomerulonephritis. Screening in this high risk population might help to identify early CKD patients and make a proper intervention strategy to prevent the disease from quick progression.

Developmental cigarette smoke exposure: kidney proteome profile alterations in low birth weight pups

The Brenner hypothesis states that a congenital reduction in nephron number predisposes to adult-onset hypertension and renal failure. The reduction in nephron number induced by proportionally smaller kidney mass may predispose offspring to glomerular hyperfiltration with maturity onset obesity. Developmental cigarette smoke exposure (CSE) results in intrauterine growth retardation with a predisposition to obesity and cardiovascular disease at maturity. Utilizing a mouse model of 'active' developmental CSE (gestational day [GD] 1-postnatal day [PD] 21; cotinine>50 ng/mL) characterized by persistently smaller offspring with proportionally decreased kidney mass, the present study examined the impact of developmental CSE on the abundance of proteins associated with cellular metabolism in the kidney. Following cessation of CSE on PD21, kidney tissue was collected from CSE and Sham exposed pups for 2D-SDS-PAGE based proteome profiling with statistical analysis by partial least squares-discriminant analysis (PLS-DA) with affected molecular pathways identified by ingenuity pathway analysis. Proteins whose expression in the kidney were affected by developmental CSE belonged to the inflammatory disease, cell to cell signaling/interaction, lipid metabolism, small molecule biochemistry, cell cycle, respiratory disease, nucleic acid and carbohydrate metabolism networks. The present findings indicate that developmental CSE alters the kidney proteome. The companion paper details the liver proteome alterations in the same offspring.

Comparison of risk prediction using the CKD-EPI equation and the MDRD study equation for estimated glomerular filtration rate

CONTEXT

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation more accurately estimates glomerular filtration rate (GFR) than the Modification of Diet in Renal Disease (MDRD) Study equation using the same variables, especially at higher GFR, but definitive evidence of its risk implications in diverse settings is lacking.

OBJECTIVE

To evaluate risk implications of estimated GFR using the CKD-EPI equation compared with the MDRD Study equation in populations with a broad range of demographic and clinical characteristics.

DESIGN, SETTING, AND PARTICIPANTS

A meta-analysis of data from 1.1 million adults (aged ≥ 18 years) from 25 general population cohorts, 7 high-risk cohorts (of vascular disease), and 13 CKD cohorts. Data transfer and analyses were conducted between March 2011 and March 2012.

MAIN OUTCOME MEASURES

All-cause mortality (84,482 deaths from 40 cohorts), cardiovascular mortality (22,176 events from 28 cohorts), and end-stage renal disease (ESRD) (7644 events from 21 cohorts) during 9.4 million person-years of follow-up; the median of mean follow-up time across cohorts was 7.4 years (interquartile range, 4.2-10.5 years).

RESULTS

Estimated GFR was classified into 6 categories (≥90, 60-89, 45-59, 30-44, 15-29, and <15 mL/min/1.73 m(2)) by both equations. Compared with the MDRD Study equation, 24.4% and 0.6% of participants from general population cohorts were reclassified to a higher and lower estimated GFR category, respectively, by the CKD-EPI equation, and the prevalence of CKD stages 3 to 5 (estimated GFR <60 mL/min/1.73 m(2)) was reduced from 8.7% to 6.3%. In estimated GFR of 45 to 59 mL/min/1.73 m(2) by the MDRD Study equation, 34.7% of participants were reclassified to estimated GFR of 60 to 89 mL/min/1.73 m(2) by the CKD-EPI equation and had lower incidence rates (per 1000 person-years) for the outcomes of interest (9.9 vs 34.5 for all-cause mortality, 2.7 vs 13.0 for cardiovascular mortality, and 0.5 vs 0.8 for ESRD) compared with those not reclassified. The corresponding adjusted hazard ratios were 0.80 (95% CI, 0.74-0.86) for all-cause mortality, 0.73 (95% CI, 0.65-0.82) for cardiovascular mortality, and 0.49 (95% CI, 0.27-0.88) for ESRD. Similar findings were observed in other estimated GFR categories by the MDRD Study equation. Net reclassification improvement based on estimated GFR categories was significantly positive for all outcomes (range, 0.06-0.13; all P < .001). Net reclassification improvement was similarly positive in most subgroups defined by age (<65 years and ≥65 years), sex, race/ethnicity (white, Asian, and black), and presence or absence of diabetes and hypertension. The results in the high-risk and CKD cohorts were largely consistent with the general population cohorts.

CONCLUSION

The CKD-EPI equation classified fewer individuals as having CKD and more accurately categorized the risk for mortality and ESRD than did the MDRD Study equation across a broad range of populations.

Chronic kidney disease and long-term outcomes of myocardial infarction

BACKGROUND

Although chronic kidney disease (CKD) is a risk factor for cardiovascular disease, information about myocardial infarction (MI) with CKD is limited in the acute revascularization era.

METHODS

To clarify the relationship between CKD and long-term outcomes of MI, consecutive 4550 patients with acute MI treated at 17 participating hospitals were analyzed. The primary study outcome was death from any cause, and a secondary endpoint was the first appearance major adverse cardiovascular events.

RESULTS

Acute revascularization therapies were performed in 75.2% of the patients and the mean left ventricular ejection fraction (LVEF) was 53%. The median follow-up was 4.1 years (follow-up rate, 95.2%). Patients were divided into four categories (<45.0, 45.0 to 59.9, 60.0 to 74.9, and ≥ 75.0 mL/min per 1.73 m(2) of body-surface area) according to the glomerular filtration rate (GFR) estimated by the Modification of Diet in Renal Disease equation. A total of 1941 (42.7%) patients had an estimated GFR of <60.0 mL/min per 1.73 m(2). Mortality rates increased with declining estimated GFR. Unadjusted hazard ratios for total and cardiovascular death in the group with an estimated GFR of 45.0 to 59.9 mL/min per 1.73 m(2) using the group with an estimated GFR of ≥ 75.0 mL/min per 1.73 m(2) as the reference were 1.63 (95% CI, 1.28 to 2.07) and 2.09 (95% CI, 1.45 to 3.01), respectively.

CONCLUSIONS

Even early-stage CKD should be considered a powerful risk factor for long-term cardiovascular death after acute MI with preserved LVEF in the acute revascularization era.

SLICC/ACR damage index independently associated with left ventricular diastolic dysfunction in patients with systemic lupus erythematosus

Left ventricular (LV) diastolic dysfunction has been reported in both active and inactive systemic lupus erythematosus (SLE) patients without clinical evidence of cardiovascular disease. However, the relationship between the long-term inflammatory burden reflected by the SLICC/ACR damage index and LV diastolic function has not been studied. Eighty-two SLE patients and 82 controls matched for age, sex, body mass index, blood pressure and heart rate underwent echocardiography with tissue Doppler imaging (TDI). LV diastolic function was estimated by the myocardial early diastolic velocity (E') at the lateral annulus. There were 51 patients (62.2%) with nephritis, 23 patients (28.0%) with hypertension, 21 patients (25.6%) with vasculitis, 16 patients (19.5%) with pulmonary hypertension, 4 patients (4.9%) with cerebrovascular disease and 2 patients (2.4%) with diabetes mellitus. Sixty-two patients (75.6%) were taking prednisone and 35 patients (42.7%) used a immunosuppressant. Forty-five patients (54.8%) had active disease and suffered from disease-related end-organ damage. Patients with SLICC/ACR damage index ≥1 had more evidence of LV diastolic dysfunction with lower lateral annulus E' (9.6 ± 3.4 vs 12.9 ± 3.5 cm/s, p < 0.001) than those without. In addition, the proportion of patients with abnormal LV myocardial relaxation (defined as lateral E' < 10.0 cm/s) (51.1% vs 16.2%, χ(2) = 10.8, p = 0.001) were significantly higher. Multivariate analysis showed that the SLICC/ACR damage index ≥1 was independently associated with LV diastolic dysfunction (OR = 3.80, 95%CI: 1.21-11.95, p = 0.023) after adjusting for hypertension, disease duration and medical therapy. This may suggest that the overall inflammatory burden in SLE, as reflected by SLICC/ACR damage index, is associated with the development of diastolic dysfunction in SLE patients.

Urinary mRNA markers of epithelial-mesenchymal transition correlate with progression of diabetic nephropathy

OBJECTIVE

Epithelial-mesenchymal transition (EMT) plays an important role in the pathogenesis and progression of diabetic nephropathy (DN). Quantification of messenger RNA (mRNA) expression in urinary sediment is emerging as a noninvasive method of screening DN-associated biomarkers. The aim of our study was to examine whether urinary mRNA profile of EMT-associated genes may provide valuable clinical insight into the different stages of DN.

DESIGN AND METHODS

Diabetic nephropathy patients (n = 44) and healthy controls (n = 12) were enrolled in this study. DN patients were divided into three groups according to the levels of estimated glomerular filtration rate (eGFR): Group A (eGFR > 60 ml/min per 1·73 m(2), n = 27), Group B (45 < eGFR < 60 ml/min per 1·73 m(2), n = 9), and Group C (eGFR < 45 ml/min per 1·73 m(2), n = 8). Relative mRNA abundance of α-smooth muscle actin (α-SMA), fibronectin, FSP1 and matrix metalloproteinase-9 (MMP-9) were quantified, and correlations between target mRNAs and clinical parameters were examined.

RESULTS

The urinary mRNA levels of α-SMA, fibronectin and MMP-9 were significantly higher in the DN group compared with controls (P < 0·05), and mRNA levels increased with DN progression. Urinary mRNA levels of all target genes positively correlated with both urinary albumin excretion (UAE) and blood urea nitrogen (BUN). Moreover, the expression of α-SMA, fibronectin and MMP-9 mRNA correlated with serum creatinine levels (r = 0·514, r = 0·53 and r = 0·469, all P < 0·001) and GFR levels (r = -0·374, r = -0·392 and r = -0·487, all P < 0·01).

CONCLUSIONS

Quantification of EMT-associated genes in urinary sediment may be a novel approach for searching new biomarkers of DN.

Pre-hypertension as a significant predictor of chronic kidney disease in a general population: the Ohasama Study

BACKGROUND

Hypertension is associated with an increased risk of development of chronic kidney disease (CKD). However, it is unclear whether pre-hypertension is related to the incidence of CKD.

METHODS

The incidence of CKD defined as positive proteinuria or estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2) was examined in 2150 inhabitants without pre-existing CKD from the general Japanese population. The association of blood pressure and CKD incidence was examined using a Cox regression model adjusted for age, sex, habitual smoking and drinking, obesity, history of cardiovascular disease, diabetes mellitus or hypercholesterolemia, eGFR at baseline, number of follow-up examinations and year of baseline examination. Participants were categorized according to the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure.

RESULTS

Participants were categorized into normotension (n = 586, 27.3 % ), pre-hypertension (n = 815, 37.9 % ), Stage 1 hypertension (n = 386, 18.0 % ) and Stage 2 hypertension (n = 363, 16.9 % ). During a mean follow-up of 6.5 years (14 023 person-years), 461 incidences of CKD were recorded. Compared to normotension, adjusted hazard ratios of CKD were significantly higher for pre-hypertension (1.49, P < 0.003), Stage 1 (1.83, P < 0.001) and Stage 2 (2.55, P < 0.001) hypertension. The population-attributable fraction of pre-hypertension (12.1 % ) was considered to be compatible to that of Stage 1 (8.6 % ) and Stage 2 (14.9 % ) hypertension.

CONCLUSION

This was the first study to demonstrate that pre-hypertension was significantly associated with an increased risk of CKD and was one of the considerable causes of CKD in the general population.

Tacrolimus improves the proteinuria remission in patients with refractory IgA nephropathy

BACKGROUND

Tacrolimus has been reported to be effective in refractory nephrotic syndrome, such as focal segmental glomerulosclerosis and membranous nephropathy. Some IgA nephropathy (IgAN) patients with massive proteinuria showed resistance to steroids and/or cytotoxic immunosuppressants based on the supportive therapy with renin- angiotensin system blockade. The efficacy and safety of tacrolimus in such refractory IgAN patients are extremely ambiguous, and the mechanism of tacrolimus improving proteinuria remission needs to be investigated.

METHODS

14 refractory IgAN patients were enrolled. The patients received tacrolimus (0.05-0.1 mg/kg/day) and prednisone (0.5 mg/kg/day) for at least 6 months. Synaptopodin and calcineurin expression were detected in renal tissues of patients who received re-biopsy. A puromycin aminonucleoside (PAN)-induced human podocyte injury model was applied to investigate the possible role of tacrolimus in proteinuria remission.

RESULTS

Of the 14 patients enrolled, 3 were withdrawn because serum creatinine increased over 30% baseline. In 11 patients treated with tacrolimus over 6 months, 9 showed complete or partial remission and 7 achieved remission within 1 month. In renal tissues, the expression of calcineurin increased while synaptopodin decreased and recovered partially after tacrolimus therapy. In an in vitro study, F-actin disrupted in human podocytes after stimulation of PAN, while calcineurin increased and synaptopodin decreased. After co-treatment with tacrolimus the reorganization of F-actin and the expression of calcineurin and synaptopodin recovered.

CONCLUSIONS

Tacrolimus showed a rapid proteinuria remission in refractory IgAN patients. The possible mechanism of tacrolimus to proteinuria remission might be podocyte cytoskeleton stabilization through inhibition of calcineurin expression.

Chronic kidney disease and the risk of stent thrombosis after percutaneous coronary intervention with drug-eluting stents

BACKGROUND

Chronic kidney disease (CKD) has been demonstrated to be associated with adverse clinical outcomes for patients with coronary artery disease (CAD). However, data on relation of CKD and stent thrombosis (ST) after drug-eluting stent (DES) implantation are limited.

OBJECTIVES

This study was designed to examine whether CKD is associated with higher incidence of ST after elective coronary DES implantation compared with patients with normal renal function.

METHODS

We consecutively enrolled 2,862 patients undergoing elective percutaneous coronary intervention (PCI) with DES. Demographic and clinical data were collected preoperatively. CKD was defined as estimated glomerular filtration rate (eGFR) < 60 ml/min, calculated using the modified MDRD equation. The primary outcome was 1-year definite or probable ST.

RESULTS

Four hundred and forty-five participants (15.5%) had CKD before procedure. The incidence of 1-year definite or probable ST was significantly higher in CKD patients compared with patients with normal renal function (1.8% vs. 0.6%, P = 0.014). After adjustment for multiple clinical and biochemical covariates, CKD was an independent predictor of 1-year definite or probable ST (hazard rate [HR] 0.396, 95% CI 0.165-0.951, P = 0.038).

CONCLUSION

CKD is significantly associated with increased incidence of 1-year definite or probable ST in patients undergoing PCI with DES.

Exposure to bisphenol A is associated with low-grade albuminuria in Chinese adults

Bisphenol A is an industrial chemical widely used in plastic products with a consequent exposure to humans. To assess whether exposure to bisphenol A is associated with renal disease, we searched for low-grade albuminuria in 3055 Chinese adults in the Shanghai metropolitan area aged 40 years or older. Using a value for urinary albumin-to-creatinine ratios <30 mg/g, we examined its association with urinary bisphenol A. Participants in the highest compared to the lowest quartile of urinary bisphenol A concentrations were significantly more likely to have low-grade albuminuria. Multivariate stepwise linear regression analysis, adjusted for potential confounding factors, showed that urinary bisphenol A was an independent determinant of the urinary albumin-to-creatinine ratio significantly associated with an increased risk of low-grade albuminuria with an adjusted odds ratio of 1.23 for the highest compared to the lowest concentration quartiles. This association was not modified by conventional risk factors such as age, gender, smoking, alcohol consumption, body mass index, hypertension, diabetes, and the estimated glomerular filtration rate. There was no significant relationship between bisphenol A and combined micro- and macroalbuminuria. Thus, our study lends support to a potential relation between bisphenol A exposure and an increased risk of low-grade albuminuria.

Uric acid and incident chronic kidney disease in a large health check-up population in Taiwan

AIM

Uric acid (UA) is strongly associated with the confirmed chronic kidney disease (CKD) risk factors, such as hypertension, diabetes and metabolic syndrome (MS); however, whether higher UA is independently associated with CKD is still debatable. Other studies found that low UA level may reflect inadequate protection against oxidant-mediated stress; it is also unknown whether hypouricemia may have a harmful effect on the kidney. No studies have examined whether there is a J-shaped relationship between UA and incident CKD.

METHODS

The association between UA and incident kidney disease (Glomerular filtration rate <60 mL/min per 1.73 m(2) ) was examined among 94 422 Taiwanese participants, aged ≥20 years with a mean 3.5 years follow-up in a retrospective cohort. The association between UA and CKD was evaluated using Cox models with adjustment for confounders.

RESULTS

The adjusted hazard ratio (HR) for incident CKD was 1.03 (95% confidence interval (CI), 1.01 to 1.06) for baseline UA level (increase by 1 mg/dL). Compared with serum UA in the first quintile (2.0 to 4.5 mg/dL), the multivariate-adjusted HR for CKD of the fifth (≥7.3 mg/dL), fourth (6.3 to 7.2 mg/dL), third (5.5 to 6.2 mg/dL), second (4.6 to 5.4 mg/dL) and hyopuricemia (<2.0 mg/dL) were 1.15 (95%CI, 1.01-1.30), 0.98 (95%CI, 0.87-1.10), 1.06 (95%CI, 0.94-1.19), 1.02 (95%CI, 0.91-1.14) and 1.65(95%CI, 0.53-5.15), respectively. The tests for the non-linear association were all not significant for both male and female. Gender-specific model revealed only the UA above 7.3 mg/dL with the increased risk of new-onset CKD in males.

CONCLUSION

Hyperuricemia is a risk factor for CKD in Taiwan, future studies are still necessary to determine whether hypouricemia increases the risk of CKD.

Chronic kidney disease prevention--a challenge for Asian countries: report of the Third Asian Forum of Chronic Kidney Disease Initiatives

As an independent meeting, the third Asian Forum of Chronic Kidney Disease Initiatives was held on April 18-19, 2009, in Kaohsiung, Taiwan. Nearly 700 participants from 17 countries attended and 78 posters were presented. To begin with, status quo in Asia and in Taiwan was briefed, followed by Theme 1A "Special Epidemiology and Risk Factors", during which the interrelations between chronic kidney disease (CKD) and use of herbs, low birth weight, infections, and immunoglobulin A (IgA) nephropathy were discussed. Theme 1B dealt with both cardiovascular and renal outcomes of CKD patients. In Theme 2, five presenters from different countries shared their experiences on "Cost-effectiveness of Community-based or Nationwide CKD Prevention Programs". In between the conference themes, three international and integrative works--Kidney Disease Improving Global Outcomes, the World Kidney Day, and Kidney Early Evaluation Program--were presented and possible implications for Asia were suggested. Theme 3 was initiated with a thorough discussion on "Equation of the Estimated Glomerular Filtration Rate for Asians" and the preliminary results of a cross-country study were presented. In Theme 4, the care plan, strategies, and outcomes of timely initiation of dialysis in different countries were discussed. The final session started with a concise summary of all speeches and ended with a position statement.

Prevalence of chronic kidney disease in China: a cross-sectional survey

BACKGROUND

The prevalence of chronic kidney disease is high in developing countries. However, no national survey of chronic kidney disease has been done incorporating both estimated glomerular filtration rate (eGFR) and albuminuria in a developing country with the economic diversity of China. We aimed to measure the prevalence of chronic kidney disease in China with such a survey.

METHODS

We did a cross-sectional survey of a nationally representative sample of Chinese adults. Chronic kidney disease was defined as eGFR less than 60 mL/min per 1·73 m(2) or the presence of albuminuria. Participants completed a lifestyle and medical history questionnaire and had their blood pressure measured, and blood and urine samples taken. Serum creatinine was measured and used to estimate glomerular filtration rate. Urinary albumin and creatinine were tested to assess albuminuria. The crude and adjusted prevalence of indicators of kidney damage were calculated and factors associated with the presence of chronic kidney disease analysed by logistic regression.

FINDINGS

50,550 people were invited to participate, of whom 47,204 agreed. The adjusted prevalence of eGFR less than 60 mL/min per 1·73 m(2) was 1·7% (95% CI 1·5-1·9) and of albuminuria was 9·4% (8·9-10·0). The overall prevalence of chronic kidney disease was 10·8% (10·2-11·3); therefore the number of patients with chronic kidney disease in China is estimated to be about 119·5 million (112·9-125·0 million). In rural areas, economic development was independently associated with the presence of albuminuria. The prevalence of chronic kidney disease was high in north (16·9% [15·1-18·7]) and southwest (18·3% [16·4-20·4]) regions compared with other regions. Other factors independently associated with kidney damage were age, sex, hypertension, diabetes, history of cardiovascular disease, hyperuricaemia, area of residence, and economic status.

INTERPRETATION

Chronic kidney disease has become an important public health problem in China. Special attention should be paid to residents in economically improving rural areas and specific geographical regions in China.

FUNDING

The Ministry of Science and Technology (China); the Science and Technology Commission of Shanghai; the National Natural Science Foundation of China; the Department of Health, Jiangsu Province; the Sichuan Science and Technology Department; the Ministry of Education (China); the International Society of Nephrology Research Committee; and the China Health and Medical Development Foundation.

The impact of renal function on outcomes of bariatric surgery

The effect of CKD on the risks of bariatric surgery is not well understood. Using the American College of Surgeons National Surgical Quality Improvement Program Participant Use File, we analyzed 27,736 patients who underwent bariatric surgery from 2006 through 2008. Before surgery, 34 (0.12%) patients were undergoing long-term dialysis. Among those not undergoing dialysis, 20,806 patients (75.0%) had a normal estimated GFR or stage 1 CKD, 5011 (18.07%) had stage 2 CKD, 1734 (6.25%) had stage 3 CKD, 94 (0.34%) had stage 4 CKD, and 91 (0.33%) had stage 5 CKD. In an unadjusted analysis, CKD stage was directly associated with complication rate, ranging from 4.6% for those with stage 1 CKD or normal estimated GFR to 9.9% for those with stage 5 CKD (test for trend, P<0.001). Multivariable logistic regression demonstrated that CKD stage predicts higher complication rates (odds ratio for each higher CKD stage, 1.30) after adjustment for diabetes and hypertension. Although patients with higher CKD stage had higher complication rates, the absolute incidence of complications remained <10%. In conclusion, these data demonstrate higher risks of bariatric surgery among patients with worse renal function, but whether the potential benefits outweigh the risks in this population requires further study.

Significant correlation between left ventricular systolic and diastolic dysfunction and decreased glomerular filtration rate

Cardiac dysfunction portends a poor prognosis in renal failure and vice versa. Functional abnormalities of heart in patients with renal insufficiency were frequently noted. The aim of this study is to assess the relationship between left ventricular systolic and diastolic function and renal function in patients with various degrees of renal function. This cross-sectional study included 167 patients from our Outpatient Department of Internal Medicine. Left ventricular systolic and diastolic functions were assessed by echocardiography. Clinical and echocardiographic parameters were compared and analyzed. The prevalence of left ventricular ejection fraction (LVEF) <50% was 31.7% and the average value of the ratio of peak early transmitral filling wave velocity (E) to early diastolic velocity of lateral mitral annulus (Ea) was 11.4 ± 6.2. After the multivariate analysis, low systolic blood pressure, rapid heart rate, low albumin, and low estimated glomerular filtration rate (eGFR) (odds ratio = 0.957; 95% confidence interval = 0.929-0.986; p = 0.004) levels were associated with LVEF < 50%. Besides, old age, low albumin, low eGFR (β = -0.172; p = 0.043), and high uric acid levels were associated with high E/Ea. Our findings show a significant correlation between LVEF < 50% and high E/Ea and decreased eGFR.

Acute kidney injury biomarkers for patients in a coronary care unit: a prospective cohort study

BACKGROUND

Renal dysfunction is an established predictor of all-cause mortality in intensive care units. This study analyzed the outcomes of coronary care unit (CCU) patients and evaluated several biomarkers of acute kidney injury (AKI), including neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18) and cystatin C (CysC) on the first day of CCU admission.

METHODOLOGY/PRINCIPAL FINDINGS

Serum and urinary samples collected from 150 patients in the coronary care unit of a tertiary care university hospital between September 2009 and August 2010 were tested for NGAL, IL-18 and CysC. Prospective demographic, clinical and laboratory data were evaluated as predictors of survival in this patient group. The most common cause of CCU admission was acute myocardial infarction (80%). According to Acute Kidney Injury Network criteria, 28.7% (43/150) of CCU patients had AKI of varying severity. Cumulative survival rates at 6-month follow-up following hospital discharge differed significantly (p<0.05) between patients with AKI versus those without AKI. For predicting AKI, serum CysC displayed an excellent areas under the receiver operating characteristic curve (AUROC) (0.895 ± 0.031, p < 0.001). The overall 180-day survival rate was 88.7% (133/150). Multiple Cox logistic regression hazard analysis revealed that urinary NGAL, serum IL-18, Acute Physiology, Age and Chronic Health Evaluation II (APACHE II) and sodium on CCU admission day one were independent risk factors for 6-month mortality. In terms of 6-month mortality, urinary NGAL had the best discriminatory power, the best Youden index, and the highest overall correctness of prediction.

CONCLUSIONS

Our data showed that serum CysC has the best discriminative power for predicting AKI in CCU patients. However, urinary NGAL and serum IL-18 are associated with short-term mortality in these critically ill patients.

Comparison of the predictive value of EuroSCORE, SYNTAX score, and clinical SYNTAX score for outcomes of patients undergoing percutaneous coronary intervention for unprotected left main coronary artery disease

OBJECTIVES

We aimed to assess the prognostic values of the EuroSCORE, SYNTAX score, and the novel Clinical SYNTAX score (CSS) for 30-day and 1-year outcomes in patients undergoing left main (LM) percutaneous coronary intervention (PCI).

BACKGROUND

PCI has become an alternative treatment for LM coronary artery disease, and risk scoring system might be beneficial for pre-PCI risk stratification.

METHODS AND RESULTS

We enrolled 198 consecutive patients with unprotected LM disease undergoing PCI (mean age 71.5 ± 10.7 years). The CSS was calculated by multiplying the SYNTAX Score to (age/left ventricular ejection fraction +1 for each 10 mL the estimated glomerular filtration rate <60 mL/min per 1.73 m(2)). The endpoints were 30-day, and 1-year all-cause death and major adverse cardiovascular events (MACE), which were defined as all-cause death, nonfatal MI, and clinical-driven target vessel revascularization. Comparing with the SYNTAX score, the predictive accuracy of CSS for 30-day and 1-year all-cause death and MACE were significantly higher (c-statistics, CSS versus SYNTAX score: P < 0.01 for 30-day and 1-year all-cause death; P < 0.05 for 30-day and 1-year MACE, respectively). Furthermore, in the multivariate Cox regression analysis, both EuroSCORE and CSS were identified as the independent predictors of 30-day and 1-year all-cause death and MACE, but the SYNTAX score was not.

CONCLUSIONS

In the general practice among a high-risk population undergoing LM PCI, EuroSCORE and CSS might be independent predictors for 30-day and 1-year all-cause death and MACE. Furthermore, the CSS had a superior discriminatory ability in predicting the 30-day and 1-year clinical outcomes comparing with the SYNTAX score.

Established and emerging markers of kidney function

BACKGROUND

The kidney performs a multitude of essential functions to maintain homeostasis. In clinical medicine, glomerular filtration rate (GFR) provides the best index of overall kidney function, and proteinuria adds additional information on renal and nonrenal prognosis. Several novel biomarkers of kidney injury and function are under investigation.

CONTENT

Plasma creatinine concentration is the most widely used measure for estimation of GFR. Plasma cystatin C and β-trace protein may eventually prove to be superior to creatinine. GFR may be measured directly by use of exogenous filtration markers, although their role is primarily limited to the research setting. Real-time, noninvasive measurement of GFR by using fluorescently labeled markers may be available in the future. Novel biomarkers of tubular injury such as neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, liver-type fatty acid binding protein, N-acetyl-β-(D)-glucosaminidase, and interleukin-18 may enable the early detection of acute kidney injury before or in the absence of a change in GFR.

SUMMARY

A variety of methods are available to assist clinicians in the assessment of kidney function and injury. Ongoing investigation will help determine the utility of several new markers and clarify their role in the care of patients with and at risk for kidney disease.

Urinary tubular biomarkers in short-term type 2 diabetes mellitus patients: a cross-sectional study

The purpose of this study was to investigate the prevalence of tubular damage in short-term (less than five years) type 2 diabetes mellitus (T2DM) patients and to explore the correlation between tubular markers and their relationship with renal indices at different stages of diabetic nephropathy. A group of 101 short-term T2DM patients and 28 control subjects were recruited. Tubular markers, such as neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-β-D: -glucosaminidase (NAG), and kidney injury molecule 1 (KIM-1), as well as urinary albumin excretion were measured in voided urine. Glomerular filtration rate (GFR) was estimated via Macisaac's formula. The patients were further categorized into three groups, namely, the normoalbuminuria, microalbuminuria, and macroalbuminuria groups, according to their urine albumin/creatinine ratio (UACR). Urinary tubular markers were compared and their correlations with renal indices [UACR and estimated GFR (eGFR)] were analyzed among the different diabetic groups. Compared with the control group, Urinary NGAL [median (IQR)][83.6(41.4-138.7) μg/gcr vs. 32.9(26.1-64.5) μg/gcr], NAG [13.5(8.7-17.9) U/gcr vs. 7.6(6.5-13.0) U/gcr] and KIM-1 [120.0(98.4-139.9) ng/gcr vs. 103.1(86.8-106.2) ng/gcr] in the T2DM were all markedly increased. For all patients, urinary NGAL had stronger positive correlations with UACR than NAG (R = 0.556 vs. 0.305, both P < 0.05). In addition, only urinary NGAL showed a negative correlation with eGFR (R = -0.215, P < 0.05). Urinary KIM-1, however, showed no significant difference among the three T2DM groups and did not correlate with either UACR or eGFR. As UACR increased from the normoalbuminuria to the last macroalbuminuria group, all of the markers increased. However, only the concentrations of NGAL were statistically different among the three diabetic groups. The correlation between the tubular markers and their relationships with the renal indices differed markedly among the three T2DM groups. In conclusion, these results suggest that tubular damage is common in short-term T2DM patients. Urinary NGAL may be a promising early marker for monitoring renal impairment in short-term T2DM patients.

Improved estimation of glomerular filtration rate (GFR) by comparison of eGFRcystatin C and eGFRcreatinine

OBJECTIVE

GFR-prediction equations based upon cystatin C and creatinine have better diagnostic performance in estimating GFR than equations based upon only one of the two markers. The present work concerns in what way a comparison between separate estimations of GFR based upon cystatin C (eGFR(cystatin C)) or creatinine (eGFR(creatinine)) can be used to evaluate the diagnostic performance of a combined cystatin C- and creatinine-based estimation of GFR.

METHODS

The difference between eGFR(cystatin C) and eGFR(creatinine) was compared with measured GFR (iohexol clearance) and a combined cystatin C- and creatinine-based estimation of GFR in a Swedish-Caucasian cohort of 857 adult patients.

RESULTS

A difference between eGFR(cystatin C) and eGFR(creatinine) of ≥ 40% indicated a markedly reduced diagnostic performance of the combined cystatin C- and creatinine-based estimation of GFR.

CONCLUSION

Comparison of the agreement between eGFR(cystatin C) and eGFR(creatinine) can be used to evaluate the diagnostic performance of combined cystatin C- and creatinine-based estimations of GFR. If 'threshold values' for discordance are exceeded, it must be considered whether the clinical context requires the use of an invasive gold standard method to measure GFR. In some clinical contexts either creatinine or cystatin C are known to be invalidated as markers of GFR and in these situations the use of only the cystatin C- or the creatinine-based GFR estimate should be considered when the 'threshold values' are exceeded.