Janak de Zoysa

Mendelian randomization analysis associates increased serum urate, due to genetic variation in uric acid transporters, with improved renal function

Increased serum urate predicts chronic kidney disease independent of other risk factors. The use of xanthine oxidase inhibitors coincides with improved renal function. Whether this is due to reduced serum urate or reduced production of oxidants by xanthine oxidase or another physiological mechanism remains unresolved. Here we applied Mendelian randomization, a statistical genetics approach allowing disentangling of cause and effect in the presence of potential confounding, to determine whether lowering of serum urate by genetic modulation of renal excretion benefits renal function using data from 7979 patients of the Atherosclerosis Risk in Communities and Framingham Heart studies. Mendelian randomization by the two-stage least squares method was done with serum urate as the exposure, a uric acid transporter genetic risk score as instrumental variable, and estimated glomerular filtration rate and serum creatinine as the outcomes. Increased genetic risk score was associated with significantly improved renal function in men but not in women. Analysis of individual genetic variants showed the effect size associated with serum urate did not correlate with that associated with renal function in the Mendelian randomization model. This is consistent with the possibility that the physiological action of these genetic variants in raising serum urate correlates directly with improved renal function. Further studies are required to understand the mechanism of the potential renal function protection mediated by xanthine oxidase inhibitors.

A Novel Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitor (GSK1278863) for Anemia in CKD: A 28-Day, Phase 2A Randomized Trial.

BACKGROUND Anemia associated with chronic kidney disease (CKD) often requires treatment with recombinant human erythropoietin (EPO). Hypoxia-inducible factor-prolyl hydroxylase inhibitors (PHIs) stimulate endogenous EPO synthesis and induce effective erythropoiesis by non-EPO effects. GSK1278863 is an orally administered small-molecule PHI. STUDY DESIGN Multicenter, single-blind, randomized, placebo-controlled, parallel-group study. SETTING & PARTICIPANTS Anemic non-dialysis-dependent patients with CKD stages 3-5 (CKD-3/4/5 group; n=70) and anemic hemodialysis patients with CKD stage 5D (CKD-5D group; n=37). INTERVENTIONS Patients with CKD-3/4/5 received placebo or GSK1278863 (10, 25, 50, or 100mg), and patients with CKD-5D received placebo or GSK1278863 (10 or 25mg) once daily for 28 days. OUTCOMES & MEASUREMENTS Primary pharmacokinetic and pharmacodynamic (increase and response rates in achieving the target hemoglobin [Hb] concentration, plasma EPO concentrations, reticulocyte count, and others]) and safety and tolerability end points were obtained. RESULTS Both CKD-3/4/5 and CKD-5D populations showed a dose-dependent increase in EPO concentrations and consequent increases in reticulocytes and Hb levels. Percentages of GSK1278863 participants with an Hb level increase > 1.0g/dL (CKD-3/4/5) and >0.5g/dL (CKD-5D) were 63% to 91% and 71% to 89%, respectively. Per-protocol-defined criteria, high rate of increase in Hb level, or high absolute Hb value was the main cause for withdrawal (CKD-3/4/5, 30%; CKD-5D, 22%). A dose-dependent decrease in hepcidin levels and increase in total and unsaturated iron binding were observed in all GSK1278863-treated patients. LIMITATIONS Sparse pharmacokinetic sampling may have limited covariate characterization. EPO concentrations at the last pharmacodynamic sample (5-6 hours) postdose may not represent peak concentrations, which occurred 8 to 10 hours postdose in previous studies. Patients were not stratified by diabetes status, potentially confounding vascular endothelial growth factor and glucose analyses. CONCLUSIONS GSK1278863 induced an effective EPO response and stimulated non-EPO mechanisms for erythropoiesis in anemic non-dialysis-dependent and dialysis-dependent patients with CKD.

End-stage renal failure due to amyloidosis: outcomes in 490 ANZDATA registry cases

BACKGROUND There are few reports regarding the long-term renal replacement therapy (RRT) outcomes of amyloidosis. METHODS In this retrospective, multi-centre, multi-country registry analysis, all patients with and without amyloidosis who commenced RRT for end-stage renal failure (ESRF) in Australia and New Zealand between 1963 and 2010 were included. RESULTS Of 58 422 patients who underwent RRT during the study period, 490 (0.8%) had ESRF secondary to amyloidosis. The median survival of amyloidosis patients on dialysis (2.09 years, 95% CI 1.85-2.32 years) was significantly inferior to that of patients with other causes of ESRF (4.45 years, 95% CI 4.39-4.51 years) (log-rank score 242, P < 0.001). The survival of amyloidosis patients receiving peritoneal dialysis (1.9 years, 95% CI 1.58-2.22) was comparable with those receiving haemodialysis (2.17 years, 95% CI 1.89-2.45) (P = 0.18). Fifty-three (13.8%) amyloidosis patients died of amyloidosis complications. Forty-six patients underwent renal transplantation with first graft survival rates of 45% at 5 years and 26% at 10 years. Nine (16.4%) patients experienced amyloidosis recurrence in their allografts, which led to graft failure in six patients. ESRF patients with amyloidosis experienced inferior median first renal allograft survival (4.55 years, 95% CI 1.96-7.15 versus 10.7 years, 95% CI 10.5-11.0, P = 0.001) and transplant patient survival (6.03 years, 95% CI 2.71-9.36 versus 16.8 years, 95% CI 16.4-17.1, P < 0.001) compared with patients with other causes of ESRF. Respective 10-year patient survival rates were 37 and 69%. CONCLUSIONS Amyloidosis was associated with poor patient survival following dialysis and/or renal transplantation, poor renal allograft survival and a significant incidence of disease recurrence in the allograft. An appreciable proportion of amyloid ESRF patients died of amyloidosis-related complications.

Rationale and design of the Sodium Lowering In Dialysate (SoLID) trial: a randomised controlled trial of low versus standard dialysate sodium concentration during hemodialysis for regression of left ventricular mass.

BackgroundThe current literature recognises that left ventricular hypertrophy makes a key contribution to the high rate of premature cardiovascular mortality in dialysis patients. Determining how we might intervene to ameliorate left ventricular hypertrophy in dialysis populations has become a research priority. Reducing sodium exposure through lower dialysate sodium may be a promising intervention in this regard. However there is clinical equipoise around this intervention because the benefit has not yet been demonstrated in a robust prospective clinical trial, and several observational studies have suggested sodium lowering interventions may be deleterious in some dialysis patients.Methods/designThe Sodium Lowering in Dialysate (SoLID) study is funded by the Health Research Council of New Zealand. It is a multi-centre, prospective, randomised, single-blind (outcomes assessor), controlled parallel assignment 3-year clinical trial. The SoLID study is designed to study what impact low dialysate sodium has upon cardiovascular risk in dialysis patients. The study intends to enrol 118 home hemodialysis patients from 6 sites in New Zealand over 24 months and follow up each participant over 12 months. Key exclusion criteria are: patients who dialyse more frequently than 3.5 times per week, pre-dialysis serum sodium of <135 mM, and maintenance hemodiafiltration. In addition, some medical conditions, treatments or participation in other dialysis trials, which contraindicate the SoLID study intervention or confound its effects, will be exclusion criteria. The intervention and control groups will be dialysed using dialysate sodium 135 mM and 140 mM respectively, for 12 months. The primary outcome measure is left ventricular mass index, as measured by cardiac magnetic resonance imaging, after 12 months of intervention. Eleven or more secondary outcomes will be studied in an attempt to better understand the physiologic and clinical mechanisms by which lower dialysate sodium alters the primary end point.DiscussionThe SoLID study is designed to clarify the effect of low dialysate sodium upon the cardiovascular outcomes of dialysis patients. The study results will provide much needed information about the efficacy of a cost effective, economically sustainable solution to a condition which is curtailing the lives of so many dialysis patients.Trial registrationAustralian and New Zealand Clinical Trials Registry number: ACTRN12611000975998

Incidence and features of dual anti‐GBM‐positive and ANCA‐positive patients

Aims:  Goodpastures syndrome, glomerulonephritis and pulmonary haemorrhage, may be due to a variety of causes. Rarely, patients with Goodpastures syndrome present with both anti‐glomerular basement membrane (GBM) and antineutrophil cytoplasmic antibody (ANCA). The aim of this report was to determine the incidence, clinical features, management and outcomes of patients presenting with concurrent ANCA and anti‐GBM disease in Auckland.

Anti-glomerular basement membrane antibody disease is an uncommon cause of end-stage renal disease

There are few reports regarding outcomes of anti-glomerular basement membrane (GBM) disease in patients who underwent renal replacement therapy. To help define this we studied all patients with anti-GBM disease who started renal replacement therapy for end-stage renal disease (ESRD) in Australia and New Zealand (ANZDATA Registry) between 1963 and 2010 encompassing 449 individuals (0.8 percent of all ESRD patients). The median survival on dialysis was 5.93 years with death predicted by older age and a history of pulmonary hemorrhage. Thirteen patients recovered renal function, although 10 subsequently experienced renal death after a median period of 1.05 years. Of the 224 patients who received their first renal allograft, the 10-year median patient and renal allograft survival rates were 86% and 63%, respectively. Six patients experienced anti-GBM disease recurrence in their allograft, which led to graft failure in two. Using multivariable Cox regression analysis, patients with anti-GBM disease had comparable survival on dialysis or following renal transplantation (hazard ratios of 0.86 and 1.03, respectively) compared to those with ESRD due to other causes. Also, renal allograft survival (hazard ratio of 1.03) was not altered compared to other diseases requiring a renal transplant. Thus, anti-GBM disease was an uncommon cause of ESRD, and not associated with altered risks of dialysis, transplant or first renal allograft survival. Death on dialysis was predicted by older age and a history of pulmonary hemorrhage.

Nephrogenic systemic fibrosis, in patients with end-stage kidney disease on dialysis, in the greater Auckland region, from 2000–2006

Aim:  Nephrogenic systemic fibrosis (NSF) is a rare and serious disease characterised by thickening and hardening of the skin with fibrosis of the dermis with CD34‐positive fibrocytes. NSF occurs in patients with renal failure and has been linked to exposure of gadolinium contrast agents. The Auckland region has a population of 1.3 million with consultation and dialysis services for patients with end stage kidney disease provided by two separate renal units. The aim of this study was to determine the incidence and frequency of NSF in the Auckland region and determine the risk based on exposure to gadolinium based contrast agents.

Troponins in Acute Kidney Injury

Abstract Aim: To investigate and describe cardiac troponins in subjects with acute kidney injury (AKI). Methods: A prospective observational study of troponin in subjects presenting with AKI in a tertiary hospital. Creatine kinase-MB (CKMB), troponin I (Abbott Laboratories), and troponin T (Roche 4th generation) were measured. Patients with conditions known to cause elevated troponin levels were excluded. Results: Nineteen subjects were enrolled in the study. Six subjects had troponin I and T concentrations above the 99th percentile of a reference population. There was high concordance of result between troponin I and troponin T. However, the concordance of elevated troponin levels with CKMB was less marked at 45%. Statistically significant factors associated with elevated troponin levels were age over 60 years, abnormal electrocardiogram, and history of previous ischemic heart disease. Conclusion: This is the first study able to demonstrate impaired renal function occurring acutely, without known confounders, results in elevated troponin levels. This suggests that impaired renal function disease influences plasma troponin levels in AKI as well as in chronic kidney failure.

A Trial of Extending Hemodialysis Hours and Quality of Life.

The relationship between increased hemodialysis hours and patient outcomes remains unclear. We randomized (1:1) 200 adult recipients of standard maintenance hemodialysis from in-center and home-based hemodialysis programs to extended weekly (≥24 hours) or standard (target 12-15 hours, maximum 18 hours) hemodialysis hours for 12 months. The primary outcome was change in quality of life from baseline assessed by the EuroQol 5 dimension instrument (3 level) (EQ-5D). Secondary outcomes included medication usage, clinical laboratory values, vascular access events, and change in left ventricular mass index. At 12 months, median weekly hemodialysis hours were 24.0 (interquartile range, 23.6-24.0) and 12.0 (interquartile range, 12.0-16.0) in the extended and standard groups, respectively. Change in EQ-5D score at study end did not differ between groups (mean difference, 0.04 [95% confidence interval, -0.03 to 0.11]; P=0.29). Extended hours were associated with lower phosphate and potassium levels and higher hemoglobin levels. Blood pressure (BP) did not differ between groups at study end. Extended hours were associated with fewer BP-lowering agents and phosphate-binding medications, but were not associated with erythropoietin dosing. In a substudy with 95 patients, we detected no difference between groups in left ventricular mass index (mean difference, -6.0 [95% confidence interval, -14.8 to 2.7] g/m2; P=0.18). Five deaths occurred in the extended group and two in the standard group (P=0.44); two participants in each group withdrew consent. Similar numbers of patients experienced vascular access events in the two groups. Thus, extending weekly hemodialysis hours did not alter overall EQ-5D quality of life score, but was associated with improvement in some laboratory parameters and reductions in medication burden. (Clinicaltrials.gov identifier: NCT00649298).

Design and participant baseline characteristics of 'A Clinical Trial of IntensiVE Dialysis': the ACTIVE Dialysis Study

Observational reports suggest extended dialysis hours are associated with improved outcomes. These findings are confounded by better prognostic characteristics among people practising extended hours. The aim of this article is to provide an overview of the methods and baseline characteristics for ACTIVE Dialysis Study participants.