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Purpose: Accurate assessment of kidney function is critical to evaluate living kidney donors. Direct glomerular filtration rate measurement using isotopes is currently the gold standard but it is complex and costly. We evaluated the performance of surrogate markers of the glomerular filtration rate in living kidney donors by comparing direct measurement of the rate to the creatinine based equation estimated rate, the kidney volume based estimated rate using a newly developed equation and creatinine clearance., Materials and Methods: We first statistically compared direct glomerular filtration rate measurement to the results of the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) creatinine based equations, and to creatinine clearance in 54 potential renal donors from 2006 to 2010. In 32 donors with cross-sectional computerized tomography available we used measured functional renal volume with age, gender, weight and serum creatinine to estimate the rate based on kidney volume according to a previously reported model. Kidney volume based measurement was compared to direct glomerular filtration rate measurement and assessed against the results of the best performing creatinine based equation., Results: In the first group of 54 donors the correlation index of the estimated glomerular filtration rate according to MDRD and CKD-EPI creatinine based equations, and to creatinine clearance was low compared to direct measurement. In the subset of 32 potential donors the kidney volume based estimated rate correlated better with direct measurement than MDRD equation results with higher accuracy (estimated 87.5% and 75.0% within 30% and 10% of direct rate measurement, respectively)., Conclusions: To estimate the glomerular filtration rate in healthy individuals a volume based model correlated better than the MDRD equation, which is the best performing creatinine based equation used to estimate the rate. By providing a more robust estimation of the glomerular filtration rate in healthy potential kidney donors, the volume based model adds value to routine preoperative computerized tomography above that of anatomical evaluation., (Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.)

Objective: The control of hypertension is often suboptimal, and it is frequently due to excessive sodium intake. Monitoring sodium intake is cumbersome and involves 24-hour collection of urine. We hypothesize that a spot urine test can accurately predict 24-hour urine sodium excretion in an Asian population., Design: This is a prospective, observational study. We used stored urine specimens (n = 333) from the Asian Kidney Disease Study and Singapore Kidney Function Study Phase I. We measured spot urine tests and correlated these variables to the previously measured 24-hour urine sodium measurements., Results: Age, gender, ethnicity, diastolic blood pressure, height, weight, body mass index, serum creatinine, spot urine sodium, spot urine chloride, and spot urine osmolality were associated with 24-hour urine sodium excretion. The final model for predicting 24-hour urine sodium less than 100 mmol included age, gender, ethnicity, weight, and spot urine sodium., Conclusion: Spot urine sodium can help monitor a patient's sodium intake when used in the derived 5-variable equation., (Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Objectives: The underlying mechanism for amphotericin B-induced acute kidney injury (AKI) remains poorly understood and may be immunologically mediated. We assessed whether the development of nephrotoxicity is linked to a distinct cytokine profile in patients receiving amphotericin B deoxycholate (AmBD)., Patients and Methods: In 58 patients who received AmBD, circulating serum interleukin (IL)-6, IL-8 and IL-10 were measured at baseline, week 1 and week 2 of antifungal treatment and correlated to the development of renal impairment. The Cox proportional hazards model approach was adopted for analysis., Results: The P value was 0.026 for the overall effect of IL-6 on time to development of AKI. An increasing or non-receding IL-6 trend by week 1 of AmBD treatment (followed by a decreasing or non-receding IL-6 trend from week 1 to week 2) correlated with an increased likelihood of nephrotoxicity [hazard ratio (HR) 6.93, P value 0.005 and HR 3.46, P value 0.035, respectively]. Similarly, persistently increasing IL-8 levels were linked to a 3.84-fold increased likelihood of AKI., Conclusions: In patients receiving AmBD, persistence of an elevated pro-inflammatory cytokine milieu is associated with a predisposition to drug-related kidney injury.

Objective: To examine the ethnic differences in the association between metabolic syndrome components and CKD in Asian populations., Methods: We analyzed data from three independent populations in Singapore representing the three major Asian ethnic groups (n=3167 Chinese, 3082 Malays and 3228 Indians) aged 40-80 years. CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m(2). Factor analysis of metabolic syndrome components was conducted and factor scores were used as independent variables in multivariable logistic regression models., Results: The prevalence of CKD was highest among Malays (21.0% vs. 7.4%, 5.9% in Indians and Chinese). Factor analysis identified three factors among Chinese (glycemia, blood pressure [BP], and obesity/lipid) and Malays (glycemia, BP, and lipids) accounting for 70% of the variance and four factors (glycemia, BP, lipids, and obesity) among Indians accounting for 82% of the variance. Glycemia was positively associated with CKD in all three ethnic groups. BP was positively associated with CKD among Malays (OR [95% CI] of 1.16 [1.06-1.28]), whereas it showed an inverse association among Chinese (0.84 [0.71-0.99]) and Indians (0.84 [0.73-0.97]). However, this inverse association lost significance after adjusting for antihypertensive medication use in Chinese and Indians. Obesity/lipids among Chinese and obesity among Indians showed a positive association; lipids showed an inverse association among Malays., Conclusions: These data suggest that while hyperglycemia was associated with CKD in all three ethnic groups, the impact of BP, lipids, obesity on CKD varies across ethnic groups. Understanding the specific associations may allow greater understanding of how CKD develops in different racial/ethnic groups., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Aim: To determine the precision of multi-frequency bioimpedance analysis (MFBIA) in quantifying acute changes in volume and nutritional status during haemodialysis, in patients with end-stage renal disease (ESRD)., Methods: Using whole-body MFBIA, we prospectively studied changes in total body water (TBW), extracellular volume (ECV), intracellular volume (ICV), lean body mass (LBM), body cell mass (BCM) and fat mass (FM), pre- and post-haemodialysis and tested the agreement of volume changes with corresponding acute weight change and ultrafiltration volume (UF) using Bland-Altman analysis., Results: Forty-four prevalent and 17 incident haemodialysis patients were studied (median age 55 years, 56% males). MFBIA-derived TBW, ECV, ICV, LBM and BCM were significantly reduced after haemodialysis (P < 0.001), but FM remained constant. TBW change estimated weight change with mean bias of -0.52 L, with 56/61 (91.8%) data points within limits of agreement (-2.74 L, 1.69 L). TBW change estimated UF with mean bias of -0.62 L, with 55/61 (90.2%) data points within limits of agreement (-2.68 L, 1.43 L). ECV change underestimated weight change and UF with mean bias of -1.17 L and -1.27 L respectively. Similarly, ICV change underestimated both clinical measures with corresponding mean bias of -1.34 L and -1.44 L. Comparing incidents versus prevalent haemodialysis patients, TBW change estimated weight change with smaller mean bias (-0.10 L vs-0.69 L, respectively) and narrower limits of agreement., Conclusion: Multi-frequency bioimpedance analysis-derived TBW chan e has the best agreement with acute clinical volume change during haemodialysis compared to ECV or ICV change alone, but overall degree of precision remains poor. Nutritional assessment using LBM and BCM measurements is significantly confounded by hydration status., (© 2012 The Authors. Nephrology © 2012 Asian Pacific Society of Nephrology.)

Background: The main objective of this study was to investigate whether plasma pentosidine levels were associated with cataract and low estimated glomerular filtration rate (eGFR) in nonproteinuric type 2 diabetic patients., Methods: We characterized 888 nonproteinuric type 2 diabetic patients residing in Singapore according to their eGFR values. Proteinuria was excluded on the basis of multiple urinalyses. Patients with low renal function (cases, n = 125) and controls (n = 763) were defined as having eGFR < and ≥60 mL/min/1.73 m(2), respectively. Pentosidine levels were measured by enzyme-linked immunosorbent assay. Multinomial logistic regression was used to test the association between plasma pentosidine levels and the joint phenotype of cataract and low eGFR., Results: Cases had higher triacylglycerol values, higher systolic blood pressure, and were more likely to be treated with two or more antihypertensive medications. In univariate analysis, cases were potentially more than twice as likely to have had a history of cataract compared with controls. This association persisted in multivariate analyses after adjusting for the significant covariates, hypertension and triacylglycerol, but was attenuated when age was included in the model. Plasma pentosidine levels were significantly higher in cases with low eGFR who also had a history of cataract. This association persisted in multivariate analyses that included the covariates, glycosylated hemoglobin, hypertension, and diabetic retinopathy, as well as age., Conclusion: Carbonyl stress, as reflected by pentosidine levels, is present in a subset of nonproteinuric diabetic patients. Clinically, this stress was associated with the joint presence of cataract and low eGFR.

Background: Hypophosphatemia is common in critically ill patients and has been associated with generalized muscle weakness, ventilatory failure and myocardial dysfunction. Continuous renal replacement therapy causes phosphate depletion, particularly with prolonged and intensive therapy. In a prospective observational cohort of critically ill patients with acute kidney injury (AKI), we examined the incidence of hypophosphatemia during dialysis, associated risk factors and its relationship with prolonged respiratory failure and 28-day mortality., Methods: This is a single-center prospective observational study. Included in the study were 321 patients with AKI on continuous dialysis as initial treatment modality., Results: Four per cent of the patients had a phosphate level <2 mg/dL at initiation and 27% during dialysis. Low baseline phosphate was associated with older age, female gender, parenteral nutrition, vasopressor support, low calcium, and high urea, bilirubin and creatinine, whereas hypophosphatemia during dialysis correlated with the ischemic acute tubular necrosis etiology of renal failure, intensive dose and longer therapy. Serum phosphate decline during dialysis was associated with higher incidence of prolonged respiratory failure requiring tracheostomy [odds ratio (OR) = 1.81; 95% confidence interval (CI) = 1.07-3.08], but not 28-day mortality (OR = 1.16; 95% CI = 0.76-1.77) in multivariable analysis., Conclusions: Hypophosphatemia occurs frequently during dialysis, particularly with long and intensive treatment. Decline in serum phosphate levels during dialysis is associated with higher incidence of prolonged respiratory failure requiring tracheostomy, but not 28-day mortality.

Introduction: The increasing prevalence of end-stage renal disease (ESRD) is an important public health issue due to the high costs of kidney replacement therapies. We examined the impact of ethnicity and other factors in ESRD management and hospitalisation in a multiracial Asian population in the fi rst year after diagnosis., Materials and Methods: We analysed a prospectively collected database of 168 new ESRD patients from the National University Hospital, Singapore (NUH) in 2005. Univariate and multivariate analyses were performed to assess factors for mortality and hospitalisation., Results: Sixteen patients eventually chose conservative treatment, 102 haemodialysis, 41 peritoneal dialysis and 9 patients underwent kidney transplantation for their long-term treatment. Although more Chinese patients had dialysis plans (56.7% vs 36.8%, P = 0.022), many still required urgent dialysis initiation via catheters (61.3%). These dialysed patients who required urgent treatment had more admissions (3.6 vs 2.6, P = 0.023) and longer length of stay (9.3 days, P = 0.014). Approximately 40 (7.4%) admissions were related to vascular access complications (thromboses, dislodgements and infections), and 15 (2.8%) were for new tunnelled catheter insertions. Deaths were 23.8% in the fi rst year after diagnosis and median survival was 125 days. Age, fi nal treatment modality, type of therapy centre, history of coronary artery disease, left ventricular ejection fraction (LVEF) <50%, and having no plans for dialysis were associated with mortality., Conclusions: The care of ESRD patients requires substantial commitment of healthcare resources particularly in the fi rst year after diagnosis. Steps to reduce urgent initiation of dialysis will help reduce resource utilisation and improve patient outcomes.

Background: In 1995, we described the technique of adapting a haemodialysis (HD) machine to produce a composition-adjustable, bicarbonate-based fluid (as our primary source for dialysate) for continuous HD in intensive care unit (ICU) patients with acute renal failure (ARF). The following studies the clinical effects, biochemical changes and economic costs of this practice in a large cohort of patients at a single centre over the last 10 years., Methods: The CCF-ARF Support Registry (1995-2001) was used to identify 405 patients initially supported with bicarbonate continuous HD. The registry is a prospective, observational cohort database that captures demographic, dialysis therapy, laboratory and outcome data. All supported ARF patients were recorded from 1995-98, and then one in five patients from 1999 to 2001. We also reviewed records of the individual dialysis procedures, dialysate disposal, dialysate monitoring tests and specific costs., Results: Continuous HD was performed for 1292 +/- 587 days from 1994 to 2004. Demographics [age 59.57 +/- 14.41 years, weight 84.2 +/- 24 kg, male 65%, chronic kidney disease (CKD) 34%] and ICU mortality (60.5%) were comparable to other reported series. Day 4 solute [BUN 52.3 mg/dl (95% CI 49.6-54.9), creatinine 2.79 mg/dl (95% CI 2.64-2.95)], electrolyte and acid-base balance [bicarbonate 24.12 mmol/l (95% CI 23.7-24.6)] were well controlled. Dialysate monitoring revealed no positive cultures or elevated endotoxin levels. Variable-composition dialysate was achieved and delivered to all patients without adverse consequences. The cost of dialysate actually declined over time (1995 = $0.91/l, 2005 = $0.67/l)., Conclusion: We have demonstrated that ICU ARF patients can be safely, effectively and economically supported with continuous HD using this source.