Risk Factors for Early Mortality in U.S. Peritoneal Dialysis Patients: Impact of Residual Renal Function

Abstract

Background Potential risk factors for 1-year mortality, including the peritoneal component of dialysis dose, residual renal function, demographic data, hematocrit, serum albumin, dialysate-to-plasma creatinine ratio, and blood pressure, were examined in a national cohort of peritoneal dialysis patients randomly selected for the Centers for Medicare and Medicaid Services End-Stage Renal Disease (ESRD) Core Indicators Project. Methods The study involved retrospective analysis of a cohort of 1219 patients receiving chronic peritoneal dialysis who were alive on December 31, 1996. Results During the 1-year follow-up period, 275 patients were censored and 200 non censored patients died. Among the 763 patients who had at least one calculable adequacy measure, the mean [± standard deviation (SD)] weekly Kt/V urea was 2.16 ± 0.61 and the mean weekly creatinine clearance was 66.1 ± 24.4 L/1.73 m2. Excluding the 365 patients who were anuric, the mean (±SD) urinary weekly Kt/V urea was 0.64 ± 0.52 (median: 0.51) and the mean (±SD) urinary weekly creatinine clearance was 31.0 ± 23.3 L/1.73 m2 (median: 26.3 L/1.73 m2). By Cox proportional hazard modeling, lower quartiles of renal Kt/V urea were predictive of 1-year mortality; lower quartiles of renal creatinine clearance were of borderline significance for predicting 1-year mortality. The dialysate component of neither the weekly creatinine clearance nor the weekly Kt/V urea were predictive of 1-year mortality. Other predictors of 1-year mortality ( p < 0.01) included lower serum albumin level, older age, and the presence of diabetes mellitus as the cause of ESRD, and, for the creatinine clearance model only, lower diastolic blood pressure. Conclusion Residual renal function is an important predictor of 1-year mortality in chronic peritoneal dialysis patients.