We examined the interrelationship between hypoalbuminemia (HA) and the normalized protein catabolic rate (NPCR; g/kg/day) in the face of adequate Kt/V and weekly creatinine clearances in 40 end-stage renal disease patients on long-term continuous ambulatory peritoneal dialysis (CAPD). We also evaluated serum albumin (SA) levels as an additional marker of nutritional status of the PD patients receiving adequate dialysis therapy in terms of Kt/V greater than 1.5 per week. Twenty-three of 40 patients had normal serum albumin (NSA; > or = 3.4 g/dL) and 17 had HA (< g/dL). A correlation between NPCR and SA levels was observed. Also, the NPCR values in patients with NSA (0.98 +/- 0.31) differ significantly (p < 0.0005) from patients with HA (0.80 +/- 0.13). Urea kinetic parameters for adequacy of dialysis, that is, Kt/V, blood urea nitrogen (BUN), and weekly creatinine clearance, did not reveal any statistically significant difference between patients with NSA and HA. These data suggest that low values of NPCR may be seen in hypoalbuminemic CAPD patients despite adequate dialysis therapy and indicate further investigation for associated morbid conditions or supplemental nutrition.