Randomized Controlled Trial Comparing Residual Kidney Function in Patients Undergoing Three or Four Exchanges CAPD

1. The primary end point for this study was changes in residual kidney function including GFR, daily urine volume (Uvol), and anuria-free survival. GFR and Uvol were evaluated within 1 week before CAPD initiation (the baseline), and then at month 1, 6, 12, 18 and 24. At the same time, body weight, blood pressure, daily net ultrafiltration, dialysis adequacy, peritoneal solute transport rate, and biochemical parameters etc. were assessed. Once an episode of peritonitis or other serious reversible intercurrent illness occurred, all the assessments were delayed one month after being cured. Anuria was termed by daily Uvol permanently less than 100 ml. 2. The secondary end points included technique survival, patient survival and peritonitis. Technique failure was defined as switching to maintenance hemodialysis.