Risk factors for early mortality in US peritoneal dialysis patients: Impact of residual renal function

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 m(2). 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 m(2) (median: 26.3 L/1.73 m(2)). 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.