Important differentiation of factors that predict outcome in peritoneal dialysis patients with different degrees of residual renal function

Background. Residual renal function (RRF) is an important predictor of outcome in peritoneal dialysis (PD) patients. Whether results from survival studies in dialysis patients with RRF can also be extrapolated to anuric patients remains uncertain. In this observational study, we examined the characteristics of PD patients with a residual glomerular filtration rate (GFR) ≥1 ml/min per 1.73 m2 vs those with complete anuria and differentiated factors that predict outcome in the two groups of patients. Methods. Two hundred and forty-six continuous ambulatory peritoneal dialysis (CAPD) patients (39% being completely anuric) were recruited from a single regional dialysis centre. Assessments of haemodynamic, echocardiographic, nutritional and biochemical parameters and indices of dialysis adequacy were done at study baseline and were related to outcomes. Results. During the prospective follow-up of 30.8 ± 13.8 (mean ± SD) months, 28.0% of patients with residual GFR ≥1 ml/min per 1.73 m2 vs 50.5% of anuric patients had died (P=0.005). The overall 2 year patient survival was 89.7 and 65.0% for patients with GFR ≥1 ml/min per 1.73 m2 and anuric patients, respectively (P=0.0012). Compared with patients with GFR ≥1 ml/min per 1.73 m2, anuric patients were dialysed for longer (P<0.001), were more anaemic (P<0.005), and had higher calcium-phosphorus product (P<0.01), higher C-reactive protein (P<0.001), lower serum albumin (P<0.05), greater prevalence of malnutrition according to subjective global assess ment (P<0.05) and more severe cardiac hypertrophy (P