Nutritional markers during peritoneal dialysis: Data from the 1998 peritoneal dialysis core indicators study

Objective: This analysis explores the nutritional status of adult U.S. peri toneal dialysis (PD) patients. Design:The Peritoneal Dialysis Core Indicators Study is a prospective cross -sectional prevalence survey describing the care provided to a random sampl e of adult U.S. PD patients. Methods and Population: Prevalence data were collected from a national rand om sample of 1381 adult PD patients participating in the United States End Stage Renal Disease (ESRD) program. Results: The median age of these patients was 55 years, 61% were Caucasian; the leading cause of ESRD was diabetes mellitus. Age, sex, size, peritonea l permeability, dialysis adequacy, and nutritional indices did not differ b etween patients on continuous ambulatory PD and patients on automated PD. T he dialysis prescriptions employed achieved mean weekly Kt/V urea (wKt/V) a nd creatinine clearance (wCCr) values of 2.22 +/- 0.57 and 67.8 +/- 22.5 L/ 1.73 m(2)/week, respectively. The PD patients were large, with a mean body weight of 77 +/- 21 kg and body mass index (BMI) of 27 +/- 8.6 kg/m(2). The mean serum albumin of these patients was 3.5 +/- 0.51 g/dL, and 43% of val ues fell below the National Kidney Foundation Dialysis Outcomes Quality Ini tiative's desired range. The PD patients had a normalized protein equivalen t of nitrogen appearance (nPNA) of 1.0 +/- 0.57 g/kg/day, a normalized crea tinine appearance rate (nCAR) of 17 +/- 7.3 mg/kg/day, and an estimated lea n body mass (%LBM) of 62% +/- 18% of body weight. Serum albumin correlated positively with patient size, nCAR, and nPNA, but negatively with age, the presence of diabetes mellitus, female gender, erythropoietin dose, the crea tinine dialysate-to-plasma ratio results of peritoneal equilibration testin g, and the dialysis portion of the wCCr. The duration of ESRD experience co rrelated negatively with both serum albumin and patient size, although thes e relationships were complex. Conclusion: Peritoneal dialysis patients generally have marginal serum albu min levels, a finding incongruent with alternative measures of nutritional status, such as weight, BMI, and creatinine generation. Serum albumin is re duced in patients with high peritoneal permeability (Le., rapid transporter s) and, because these patients generally have higher than average wCCr valu es, serum albumin is inversely correlated with the dialysis component of th e wCCr. The presumptive nutritional indicators (BIVII, %LBM, nPNA, and seru m albumin) provide disparate estimates, varying from 10% to 50% for the pre valence of nutritionally stressed PD patients.