Chi Bon Leung

The Oxford classification of IgA nephropathy: rationale, clinicopathological correlations, and classification

IgA nephropathy is the most common glomerular disease worldwide, yet there is no international consensus for its pathological or clinical classification. Here a new classification for IgA nephropathy is presented by an international consensus working group. The goal of this new system was to identify specific pathological features that more accurately predict risk of progression of renal disease in IgA nephropathy, thus enabling both clinicians and pathologists to improve individual patient prognostication. In a retrospective analysis, sequential clinical data were obtained on 265 adults and children with IgA nephropathy who were followed for a median of 5 years. Renal biopsies from all patients were scored by pathologists blinded to the clinical data for pathological variables identified as reproducible by an iterative process. Four of these variables: (1) the mesangial hypercellularity score, (2) segmental glomerulosclerosis, (3) endocapillary hypercellularity, and (4) tubular atrophy/interstitial fibrosis were subsequently shown to have independent value in predicting renal outcome. These specific pathological features withstood rigorous statistical analysis even after taking into account all clinical indicators available at the time of biopsy as well as during follow-up. The features have prognostic significance and we recommended they be taken into account for predicting outcome independent of the clinical features both at the time of presentation and during follow-up. The value of crescents was not addressed due to their low prevalence in the enrolled cohort.

Outcome of IgA nephropathy in adults graded by chronic histological lesions

This prognostic study of primary immunoglobulin A (IgA) nephropathy focused on chronic irreversible glomerular sclerosis and interstitial fibrosis, based on the premise that this disease is characterized by a protracted and, for many, progressive course. We used a chronicity-based histological grading system to assess the biopsy specimens of 126 adults with IgA nephropathy over a median follow-up of 10 years. Our grading system included a glomerular grading (GG) of 1 to 3 based on the extent of glomerular sclerosis, a tubulointerstitial grading (TIG) of 1 to 3 based on the degree of tubular loss or interstitial fibrosis, and the evaluation of hyaline arteriolosclerosis (HA). These three histological parameters were correlated with each other and with serum creatinine level, degree of proteinuria, and blood pressure at the time of renal biopsy. Univariate analysis showed that these three histological and three clinical parameters were significantly correlated with renal survival. By multivariate analysis using the Cox regression model, GG, serum creatinine level, and degree of proteinuria represented independent prognostic factors of renal survival. For a subset of patients at a relatively early stage of disease with a serum creatinine level less than 130 micromol/L at the time of biopsy, all three histological features and degree of proteinuria were significantly correlated with renal survival, and GG was the only independent prognostic factor for renal outcome. This study shows that glomerular sclerosis represents the most important prognostic factor in adult patients with primary IgA nephropathy and has a strong predictive value. Our chronicity-based histological grading system not only correlates well with the natural history of IgA nephropathy but is also reproducible and relatively simple to apply.

Antibody Response to Hepatitis B Vaccine in End-Stage Renal Disease Patients

Background: This retrospective and comparative study evaluated the relationship between different factors which may contribute to suboptimal immunological response to intramuscular recombinant hepatitis B vaccine in end-stage renal disease (ESRD) subjects. Methods: From a cohort of 64 dialysis subjects undergoing primary vaccination with Engerix-B®, we determined the predictive factors that impinged on patients’ response to vaccine, as defined by anti-HBs level ≧10 mIU/l. Dose efficacy was further evaluated by comparing three historical cohorts vaccinated by the regimens of 20, 40 and 80 µg/dose, respectively. Results: We identified 64 ESRD patients (mean age 43 ± 12 years, 81% receiving peritoneal dialysis) who received primary vaccination from April 1997 to September 2004. Median follow-up was 6.5 years. They achieved 81% seroconversion rate. Older age, diabetes mellitus, obesity and low Engerix-B dose were risk factors of inadequate anti-HBs response by univariate analysis. By stepwise logistic regression analysis, hepatitis B vaccine dose was the only independent predictive factor of impaired antibody response. An Engerix-B vaccine dose of 20 µg was associated with more than tenfold increase in risk of non-response to hepatitis B vaccine (hazards ratio 32.2 (95% CI 3.85–250.0)). Immunization with 80 µg of Engerix-B increased the likelihood of persistent protective antibody (log-rank test, p = 0.014). Immunization with Engerix-B 80-µg dose is estimated to prevent one extra ESRD subject who would lose seroprotective anti-HBs level at 1 year for every 5.6 patients treated (number needed to treat to benefit, 5.6 (95% CI 5.4–5.8)). Conclusions: Our results suggest the potential for the three-dose schedule of recombinant vaccine Engerix-B 80 µg to prolong the immune response among ESRD population.

Predictive Value of Dialysate Cell Counts in Peritonitis Complicating Peritoneal Dialysis

Early prediction of outcomes has major potential implications regarding the management of dialysis-related peritonitis. The outcomes of 565 consecutive episodes of peritonitis complicating peritoneal dialysis between August 2001 and July 2005 were evaluated in relation to the dialysate cell counts. Discriminatory power, based on the area under the receiver-operating characteristic (ROC) curves, of the cell counts was assessed. The findings then were validated externally in a cohort of 217 peritonitis episodes from another dialysis unit. During the study period, 565 episodes of peritonitis were included for analysis, 465 of which had treatment success defined as complete resolution of peritonitis without the need for Tenckhoff catheter removal. Of the remaining 100 episodes (treatment failure), 70 required Tenckhoff catheter removal and 30 had peritonitis-related death. The peritoneal dialysate total white blood cell count on day 3 of peritonitis predicted treatment failure independent of standard risk factors, and it had a higher area under the ROC curve than the dialysate white cell count on day 1 (0.80 versus 0.58; P < 0.0001). Using a peritoneal dialysate white count cut point > or = 1090/mm3 on day 3, the sensitivity was 75% and the specificity was 74% for the prediction of treatment failure (defined as catheter loss or peritonitis-related death). In multiple logistic regression analyses, peritoneal dialysate white count > or = 1090/mm3 on day 3 was an independent prognostic marker for treatment failure after adjustment for conventional risk factors (hazard ratio 9.03; 95% confidence interval 4.40 to 18.6; P < 0.0001). Number of years on peritoneal dialysis; diabetes; gram-negative organisms; and Pseudomonas, fungal, or Mycobacterium species were other independent risk factors that were predictive of treatment failure. Findings from an independent validation set of peritonitis (217 episodes after exclusion of Mycobacterium and fungal causes) also favored the peritoneal dialysate white count on day 3, as compared with day 1 and day 2, to predict treatment failure. Area under the ROC curve for the white counts on day 3 was 0.98 (95% confidence interval 0.95 to 0.99) in the validation set. This study demonstrated and cross-validated the superiority of peritoneal dialysate white cell count on day 3 to predict outcomes of dialysis-related peritonitis. These results call attention to the value of validating prognostic factors of peritonitis complicating peritoneal dialysis.

Comparison of double-bag and Y-set disconnect systems in continuous ambulatory peritoneal dialysis: a randomized prospective multicenter study.

We performed a multicenter, single-blinded, prospective randomized study on the use of a double-bag disconnect system (B) versus a Y-set disconnect system (Y). The peritonitis rate, exit site infection, clinical outcome, and patients acceptance to the procedure were assessed. A total of 120 new end-stage renal failure patients of three regional hospitals were randomized: 60 each to the B and the Y systems. The results of 60 patients on the B system and 51 on the Y system were analyzable. They were followed up for a median of 16 months. Peritonitis rates for the B and the Y systems were 33.5 and 29.4 patient-months per episode, respectively. Exit site infection rates for the B and Y systems were 17.4 and 16.0 patient-months per episode, respectively. Four catheters were removed in each group. Patients on the B system were hospitalized for 2.1 days per patient per year related to peritonitis and exit site infection, and those on the Y system were hospitalized for 1.2 days. There was no significant difference between the B and Y systems in the incidences of peritonitis (all causes and those due to coagulase-negative staphylococci), exit site infection, and in hospitalization days. However, there was a higher percentage of gram-positive infections in the Y system (52%) than in the B system (32%) and a lower percentage of gram-negative infections in the Y system (16%) than in the B system (32%). Patients on the B system had a better acceptance of the procedure than patients on the Y system, as assessed by a six-item, 10-point questionnaire (total score, 43.1 +/- 10.2 v 37.6 +/- 9.4; P < 0.005 at 1 month; 44.6 +/- 9.1 v 39.8 +/- 8.6; P < 0.01 at 6 months). From this study, it is concluded that the B and Y systems are similar in the incidences of peritonitis and exit site infection, although the B system is better accepted by patients. This is probably the first multicenter randomized study comparing the double-bag and Y-set disconnect system using only new patients who had never used other systems of continuous ambulatory peritoneal dialysis.

Posttransplant Epstein-Barr virus-associated myogenic tumors involving bone: A case report

Epstein–Barr virus (EBV)–associated myogenic tumors in immunocompromised patients were recently recognized, but their biologic behavior remains only partially understood. Although observations so far have permitted the recognition of similarities between posttransplant myogenic tumors and posttransplant lymphoproliferative disorders (PTLD), the number of reports are still few, and new experiences continue to be informative.

Plasma Exchange in the Treatment of Early Recurrent Focal Glomerulosclerosis after Renal Transplantation

We report a 29-year-old female with recurrent focal glomerulosclerosis (FGS) presenting as heavy proteinuria immediately following renal transplantation. From day 13 after transplantation, daily plasma exchange was performed 6 times. Proteinuria decreased from 13 to 0.2 g/day after plasma exchange and remained to be less than 0.1 g/day even 20 months thereafter. Our review of the literature on the use of plasma exchange in treating recurrent FGS suggests this procedure is not useful in patients whose allograft biopsy showed advanced glomerular sclerotic lesions. We propose early plasma exchange may be a therapeutic option in those patients who have no sclerotic lesions in their allograft biopsy.

Renal registry in Hong Kong—the first 20 years

Renal Registry was started by the Hospital Authority (HA) in Hong Kong in 1995. It is an online system developed by HA. It collects all patients under care in HA, which is about 90–95 % of all requiring renal replacement therapy (RRT) in Hong Kong. The total number of patients treated increased from 3312 in 1996 to 8510 in 2013. In 2013, there were 3501 renal transplant, 1192 hemodialysis (HD) and 3817 peritoneal dialysis (PD) patients. In 2013, 1147 new patients joined the RRT program, 49.6% of them suffered from diabetic nephropathy. Glomerulonephritis and hypertension are the 2nd and 3rd most common causes of RRT in Hong Kong. The median age was 59.1 years with male to female ratio of 1.54 to 1. Hong Kong practices ‘PD first policy and the majority of the patients are on CAPD treatment. The ratio of PD to HD was 76.2% to 23.8%. Eighty-six percent of all PD patients are on CAPD; the remaining 14% are on automated peritoneal dialysis (APD). Sixty-five percent of all dialysis patients are on erythropoiesis-stimulating agent treatment. The Hong Kong Renal Registry with online real-time data input and access can provide timely data and information to facilitate patient care and management and also provides invaluable data to help in development and planning of renal services in Hong Kong.

Increasing home based dialysis therapies to tackle dialysis burden around the world: a position statement on dialysis economics from the 2nd Congress of the International Society for Hemodialysis

PHILIP KAM-TAO LI, WAI LUN CHEUNG, SING LEUNG LUI, CHRISTOPHER BLAGG, ALAN CASS, LAI SEONG HOOI, HO YUNG LEE, FRANCESCO LOCATELLI, TAO WANG, CHIH-WEI YANG, BERNARD CANAUD, YUK LUN CHENG, HUI LIN CHOONG, ANGEL L DE FRANCISCO, VICTOR GURA, KAZO KAIZU, PETER G KERR, UN I KUOK, CHI BON LEUNG, WAI-KEI LO, MADHUKAR MISRA, CHEUK CHUN SZETO, KWOK LUNG TONG, KRIANG TUNGSANGA, ROBERT WALKER, ANDREW KUI-MAN WONG, ALEX WAI-YIN YU, on behalf of the participants of THE ROUNDTABLE DISCUSSION ON DIALYSIS ECONOMICS in the SECOND CONGRESS OF THE INTERNATIONAL SOCIETY FOR HEMODIALYSIS (ISHD 2009)*

Body mass index as a predictive factor for long‐term renal transplant outcomes in Asians

Abstract:u2002 Background:u2002 There is substantial evidence that renal transplant recipients with obesity or body mass index >30u2003kg/m2 have increased risk of graft loss. However, few data exist for Asian population; clinicians have to rely upon indirect evidence by extrapolating the results from Caucasians to Asian recipients.