Clinical performance measures: The changing status of peritoneal dialysis

Background. The Peritoneal Dialysis-Clinical Performance Measures Project (PD-CPM) characterizes peritoneal dialysis within the U.S. Current survey results are reported and compared to those of previous years. Methods. Prevalence data from random national samples of adult peritoneal dialysis (PD) patients participating in the United States End-Stage Renal Disease (ESRD) program have been collected annually since 1995. Results. In 1995, 79% of the respondents used continuous ambulatory peritoneal dialysis (CAPD) rather than automated peritoneal dialysis (APD). The mean hematocrit (Hct) of PD patients was 32% and only 66% of individuals had a measurement of dialysis adequacy reported. The mean weekly Kt/V_urea (wKt/V) and weekly creatinine clearance (wC_Cr) reported for CAPD patients in 1995 were 1.9 and 67 L/1.73 m²/week, respectively. In 2000 the median age of PD patients was 55 years and 63% were white. The leading cause of ESRD was diabetes mellitus (34%) and 54% of adult PD patients performed some form of APD rather than CAPD. Age, sex, size, hematocrit, peritoneal permeability, dialysis adequacy, residual renal function and nutritional indices did not differ between APD and CAPD patients. The mean hemoglobin (Hb) for the 2000 PD-CPM population was 11.6 ± 1.4 g/dL (mean ± 1 SD) and 11% of patients had an average Hb below 10 g/dL. The average serum albumin was 3.5 ± 0.5 g/dL by the bromcresol green method and 56% of subjects had an average serum albumin equal to or above 3.5 g/dL (or 3.2 g/dL by bromcresol purple). In 2000 85% of patients had a dialysis adequacy measurement reported and the mean calculated wKt/V and wC_Cr were 2.3 ± 0.6 and 72.7 ± 24.9 liters/1.73 m²/week for CAPD patients and 2.3 ± 0.6 and 71.6 ± 25.1 L/1.73 m²/week for APD patients. PD subjects had a mean body weight of 76 ± 19 kg and body mass index (BMI) of 27.5 ± 6.4 kg/m². The protein equivalent of nitrogen appearance (nPNA) of these patients was 0.95 ± 0.31 g/kg/day, their normalized creatinine appearance rate (nCAR) equaled 17 ± 6.5 mg/kg/day, resulting in a percent lean body mass (%LBM) of 64 ± 17% of actual body weight. Serum albumin correlated in a positive fashion with BMI, nPNA, nCAR and %LBM, but not with wC_Cr. Conclusions. The majority of indicator variables monitored by the PD-CPM have improved since 1995. PD patients have higher hemoglobins and a greater proportion of patients meet the criteria for adequate dialysis. Serum albumin values, however, remain marginal and unchanged over the five-year project. Furthermore, serum albumin values fail to correlate with the intensity of renal replacement therapy and are not strongly correlated with alternative estimates of nutritional status.