title: Peritoneal urea and creatinine clearances in continuous peritoneal dialysis patients with different types of peritoneal solute transport.
abstract: We studied whether anuric subjects on continuous ambulatory peritoneal dialysis (CAPD) who achieve the target Kt/V urea of 2.0 weekly will also achieve the target normalized creatinine clearance (NCCr) of 60 liter/1.73 m2 weekly, and the reasons of discrepancy between the two clearances in anuric subjects, by analyzing 476 clearance studies performed in 309 CAPD patients within 12 months of the performance of a peritoneal equilibration test (PET). On the basis of the PET, peritoneal solute transport was classified as low (37 clearance studies), low-average (199 studies), high-average (186 studies) and high (54 studies). We found that weekly values of Kt/V urea in the low transport group (LTG) 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 analysis). Weekly values for NCCr, liter/1.73 m2 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 clearance 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 results: LTG, y = 19.486 + 10.500x, r = 0.591 [if x = 2.0, y = 15.004 + confidence interval (95% CI) of y 25.3 to 55.7]; LATG, y = 15.0004 + 17.482x, r = 0.774 (if x = 2.0, y = 50.0, 95% CI of y 38.4 to 61.6); HATG, 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 insignificant effect on peritoneal urea clearance. Consequently, the majority of anuric patients who achieve a weekly Kt/V urea of 2.0 will have a weekly NC cr lower than 60 liter/1.73 m2 and will require a Kt/V urea much higher than 2.0 to achieve the target NCcr of 60 liter/1.73 m2 weekly. The current targets of urea and creatinine clearance are not compatible in anuric patients on CAPD.
authors.affiliation: Renal Section, Albuquerque Veterans Affairs Medical Center, New Mexico, USA.
authors.forename: A H
authors.initials: AH
authors.lastname: Tzamaloukas
authors.forename: G H
authors.initials: GH
authors.lastname: Murata
authors.forename: B
authors.initials: B
authors.lastname: Piraino
authors.forename: P
authors.initials: P
authors.lastname: Rao
authors.forename: J
authors.initials: J
authors.lastname: Bernardini
authors.forename: D
authors.initials: D
authors.lastname: Malhotra
authors.forename: D G
authors.initials: DG
authors.lastname: Oreopoulos
mesh_terms: D000328:Adult; D000368:Aged; D001002:Anuria / Q000097:blood / Q000378:metabolism / Q000628:therapy; D001693:Biological Transport, Active; D003404:Creatinine / Q000097:blood / Q000378:metabolism*; D015314:Dialysis Solutions; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000378:metabolism / Q000628:therapy; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory; D010537:Peritoneum / Q000378:metabolism*; D014508:Urea / Q000097:blood / Q000378:metabolism*
chemical_list: D015314:Dialysis Solutions; D014508:Urea; D003404:Creatinine