Predictors of Residual Renal Function Decline in Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

BACKGROUND: Residual renal function (RRF) is an important prognostic indicator in continuous ambulatory peritoneal dialysis (CAPD) patients. We determined the predictors of RRF loss in a cohort of incident CAPD patients. METHODS: We reviewed the record of 645 incident CAPD patients. RRF loss is represented by the slope of decline of residual glomerular filtration rate (GFR) as well as the time to anuria. RESULTS: The average rate of residual GFR decline was -0.083 ± 0.094 mL/min/month. The rate of residual GFR decline was faster with a higher proteinuria (r = -0.506, p < 0.0001) and baseline residual GFR (r = -0.560, p < 0.0001). Multivariate analysis showed that proteinuria, baseline residual GFR, and the use of diuretics were independent predictors of residual GFR decline. Cox proportional hazard model showed that proteinuria, glucose exposure, and the number of peritonitis episodes were independent predictors of progression to anuria, while a higher baseline GFR was protective. Each 1 g/day of proteinuria is associated with a 13.2% increase in the risk of progressing to anuria, each 10 g/day higher glucose exposure is associated with a 2.5% increase in risk, while each peritonitis episode confers a 3.8% increase in risk. CONCLUSIONS: Our study shows that factors predicting the loss of residual solute clearance and urine output are different. Proteinuria, baseline residual GFR, and the use of diuretics are independently related to the rate of RRF decline in CAPD patients, while proteinuria, glucose exposure, and the number of peritonitis episodes are independent predictors for the development of anuria. The role of anti-proteinuric therapy and measures to prevent peritonitis episodes in the preservation of RRF should be tested in future studies.