PERITONEAL UREA AND CREATININE CLEARANCES IN CONTINUOUS PERITONEAL-DIALYSIS PATIENTS WITH DIFFERENT TYPES OF PERITONEAL SOLUTE TRANSPORT

We studied whether anuric subjects on continuous ambulatory peritoneal dialysis (CAPD) who achieve the target Kt/V urea of 2.0 weekly will a lso achieve the target normalized creatinine clearance (NCCr) of 60 li ter/1.73 m(2) weekly, and the reasons of discrepancy between the two c learances in anuric subjects, by analyzing 476 clearance studies perfo rmed in 309 CAPD patients within 12 months of the performance of a per itoneal equilibration test (PET). On the basis of the PET, peritoneal solute transport was classified as low (37 clearance studies), low-ave rage (199 studies), high-average (186 studies) and high (54 studies). We found that weekly values of Kt/V urea in the low transport group (L TG) was 1.74 +/- 0.51, in the low-average transport group (LATG) was 1 .66 +/- 0.41, in the high-average transport group (HATG) 1.68 +/- 0.41 , and in the high transport group (HTG) 1.73 +/- 0.46 (NS, variance an alysis). Weekly values for NCCr, liter/1.73 m(2) were: LTG, 37.8 +/- 9 .0; LATG, 44.0 +/- 9.2; HATG, 49.2 +/- 10.0; HTG 56.8 +/- 13.3 (P < 0. 0001). The ratios of raw (not-normalized) peritoneal creatinine cleara nce to peritoneal urea clearance were: LTG, 0.65 +/- 0.14; LATG, 0.76 +/- 0.09; HATG, 0.84 +/- 0.09; HTG. 0.91 +/- 0.12 (P < 0.0001). Linear regression with Kt/V urea as x and NCCr as y revealed the following r esults: LTG, y = 19.486 + 10.500x, r = 0.591 [if x = 2.0, y = 40.5, 95 % confidence interval (95% CI) of y 25.3 to 55.7]; LATG, y = 15.004 17.482x, r = 0.774 (if x = 2.0, y = 50.0, 95% CI of y 38.4 to 61.6); H ATG, y = 15.285 + 20.162x, r = 0.829 (if x = 2.0, y = 55.6, 95% CI of y 44.4 to 66.8); HTG, y = 14.945 + 24.134x, r = 0.839 (if x = 2.0, y = 63.2, 95% CI of y 48.4 to 78.1). Peritoneal solute transport type has a major effect on peritoneal creatinine clearance, but an insignifica nt effect on peritoneal urea clearance. Consequently, the majority of anuric patients who achieve a weekly Kt/V urea of 2.0 will have a week ly NCCr lower than 60 liter/1.73 m(2) and will require a Kt/V urea muc h higher than 2.0 to achieve the target NCCr of 60 liter/1.73 m(2) wee kly. The current targets of urea and creatinine clearance are not comp atible in anuric patients on CAPD.