High creatinine excretion ratio predicts a good outcome in peritoneal dialysis patients

The creatinine excretion (CrEx) ratio was first described as a method for d etecting noncompliance in peritoneal dialysis (PD) patients. However, a hig h CrEx ratio is not specific for noncompliance and may also be found in com pliant patients with a relatively greater lean body mass (LBM). A cohort of 44 PD patients was followed up for a mean of 13 +/- 8 months after measure ment of baseline CrEx ratio to investigate whether greater values were pred ictive of good or poor clinical outcomes. During this follow-up, 11 patient s died, 12 patients transferred to hemodialysis, 4 patients underwent trans plantation, 1 patient recovered renal function, and 16 patients continued o n PD. The mean CrEx ratio in all patients was 1.14 +/- 0.32. It did not dif fer between men and women (1.15 versus 1.13, respectively; P = 0.76) but sh owed a trend toward being less in patients with diabetes (1.03 versus 1.19; P = 0.19). The mean weekly Kt/V, weekly creatinine clearance, normalized p rotein equivalent of nitrogen appearance, and serum albumin values were 2.1 8 +/- 0.57, 73.57 +/- 33.75 L/1.73 m(2), 0.80 +/- 0.22 g/kg/d, and 3.22 +/- 0.59 g/dL, respectively. Technique failure (P < 0.001) and death (P < 0.05 ) were significantly more common in patients with a CrEx ratio less than 1 compared with those with a CrEx ratio greater than 1. On Cox regression ana lysis, the CrEx ratio was the only significant predictor of technique failu re and was also an independent predictor of death. High CrEx ratio is a pre dictor of good, rather than poor, outcome in PD patients, perhaps because i t is primarily an index of nutrition. This further weakens the argument tha t it is a reliable or useful marker of noncompliance. (C) 2000 by the Natio nal Kidney Foundation, Inc.