Water and small solute excretion in continuous peritoneal dialysis patients with lean body mass exceeding 90% of body weight as estimated from creatinine kinetics

wwLean body mass computed from creatinine kinetics (LBM) is an index of som atic nutrition and correlates with other nutrition indices in CAPD. However , LBM exceeding 90% of body weight (LBM/W greater than or equal to 0.9) may be an index of non-compliance, rather than nutrition. To test this hypothe sis, we analyzed fluid and solute excretion in 40 CAPD patients with LBM/W ? 0.9 (group A). The comparison group (group B) consisted of 885 CAPD patie nts with LBM/W < 0.9. Group A was younger (38.3 +/- 14.8 vs 54.7 +/- 14.7 y r) and had a lower percent of women (23.5% vs 41.1%) and diabetic subjects (17.5% vs 42.6%) than group B (at P < 0.019). Group A also had lower body m ass index (22.7 +/- 12.7 vs 25.8 +/- 15.1 kg/m(2), P <0.001) and serum albu min (33.0 +/- 6.7 vs 35.2 +/- 5.5 g/L, P = 0.014). Despite similar prescrib ed daily fill volumes (group A 8.3 +/- 2.4, group B 8.5 +/- 2.2 L/24 h) and similar DIP urea and creatinine values, group A had higher daily drain vol ume (11.0 +/- 3.6 vs 9.6 +/- 2.1 L/24 h, P < 0.001). Renal clearances were similar, while peritoneal and total clearances were apparently higher in gr oup A. Creatinine excretion was higher in group A (27.4 +/- 15.1 vs 13.6 +/ - 14.1 mg/kg x 24 h, P < 0.001), with a large part of the excess creatinine excretion in group A being accounted for by peritoneal excretion. The comb ination of an apparently high daily ultrafiltration volume (2.7 L/24 h on t he average), unrealistically high creatinine excretion rate, and relatively poor nutrition (low body mass index and serum albumin) in group A is consi stent with non-compliance. We suggest that the finding of LBM/W greater tha n or equal to 0.9 during a clearance study in CAPD should trigger an invest igation for non-compliance.