Blog entry by Meguid El Nahas

Anyone in the world
The BalANZ study (David Johnson and Colleagues J Am Soc Nephrol 23: ccc–ccc, 2012. doi: 10.1681/ASN.2011121201)

More than 15 years ago Wieslander and co-workers working in Lund, Sweden, identified a number of components of peritoneal dialysis solutions that are potentially damaging both in mesothelial cells in culture as well as in vivo. Among these are the glucose degradation products (GDP) that occur when glucose containing solutions are sterilised at high temperature. In order to reduce the formation of these agents a new generation of peritoneal dialysis solutions based on 2 separate compartments were developed where the glucose component was sterilised at a very low pH (2-3) in order to reduce GDP formation and then combined with a buffer to neutralise the pH just prior to infusion into the patient. There have been several clinical studies that have explored the clinical benefit of these new solutions but the benefits have not been clearly demonstrated. Against this background the eagerly awaited BalANZ study has just been published in JASN and is important since it is the largest randomised controlled trial of biocompatible peritoneal dialysate vs standard dialysate to date. The investigators are to be congratulated for persisting despite recruitment difficulties, and successfully recruiting 185 incident peritoneal dialysis patients to this 2 year study. Patients were randomized 1:1 to receive either a neutral pH, lactate buffered, low GDP Balance solution (Fresenius Medical Care, Bad Homburg, Germany) or a conventional, standard, lactate-buffered PD solution (stay.safe).

The primary outcome measure was the difference in the slope of the decline in residual renal function and this was not met. However there was a significant difference between the groups both in time to anuria (p=0.009) and time to first peritonitis episode (p=0.01) in favour of the more biocompatible solution. Indeed the peritonitis rate in the biocompatible group was 0.30 vs 0.49 (p=0.01) episodes per year. In addition there was a significant reduction in over all infection in the biocompatible group (4 non PD infections out of 91 patients vs 20 out of 91 in the control group). Thus the biocompatible group demonstrated meaningful benefits in terms of infection and time to anuria compared with the control solution.

As usual with studies of this kind there are several caveats – for example few patients were on automated peritoneal dialysis and the use of icodextrin was relatively low. There was also a difference in ultrafiltration between the groups with lower 24 hour ultrafiltration in the Balance group at 3 and 6 months, although there was no significant difference in dialysate glucose concentrations used. Unfortunately, this study did not report information on membrane function. Furthermore it is not clear that the results would be apply to other types of more biocompatible solutions since the concentrations of glucose degradation products vary between the types – for example Physioneal (Baxter) is reported to contain higher concentrations of 3-deoxyglucosone than the Balance solution. Clearly this study has to be considered in light of those that have gone before where the value for biocompatible solutions has not been clearly demonstrated. However it gives an important signal of a significant benefit for the more biocompatible solution for two important outcome measures in patients on peritoneal dialysis – time to anuria and peritonitis rates. Progress in medicine is incremental, and although this study has not answered all the outstanding questions on the impact of solution design on patient outcomes in PD, it has provided important information relevant to patients and their clinical teams.
[ Modified: Thursday, 1 January 1970, 1:00 AM ]