Rationale and design of the balANZ trial: A randomised controlled trial of low GDP, neutral pH versus standard peritoneal dialysis solution for the preservation of residual renal function

Background: The main hypothesis of this study is that neutral pH, low glucose degradation product (GDP) peritoneal dialysis (PD) fluid better preserves residual renal function in PD patients over time compared with conventional dialysate. Methods/Design: Inclusion criteria are adult PD patients (CAPD or APD) aged 18-81 years whose first dialysis was within 90 days prior to or following enrolment and who have a residual GFR >= 5 ml/min/1.73 m(2), a urine output >= 400 ml/day and an ability to understand the nature and requirements of this trial. Pregnant or lactating patients or individuals with an active infection at the time of enrolment, a contra-indication to PD or participation in any other clinical trial where an intervention is designed to moderate rate of change of residual renal function are excluded. Patients will be randomized 1: 1 to receive either neutral pH, low GDP dialysis solution (Balance (R)) or conventional dialysis solution (Stay.safe (R)) for a period of 2 years. During this 2 year study period, urinary urea and clearance measurements will be performed at 0, 3, 6, 9, 12, 18 and 24 months. The primary outcome measure will be the slope of residual renal function decline, adjusted for centre and presence of diabetic nephropathy. Secondary outcome measures will include time from initiation of peritoneal dialysis to anuria, peritoneal small solute clearance, peritoneal transport status, peritoneal ultrafiltration, technique survival, patient survival, peritonitis rates and adverse events. A total of 185 patients has been recruited into the trial. Discussion: This investigator-initiated study has been designed to provide evidence to help nephrologists determine the optimal dialysis solution for preserving residual renal function in PD patients.