Variability in creatinine clearance (CCR) and KT/V due to different methods of calculating volume and CCR.
OBJECTIVE
This study aimed to compare the correlations between KT/V and creatinine clearance (Ccr) calculated by different methods and to determine and compare the correlations between KT/V and Ccr.


METHODS
Nonrandomized, retrospective analysis of data.


METHODS
Continuous ambulatory peritoneal dialysis (CAPD) outpatient clinic in a teaching hospital.


METHODS
All patients were included for analysis if the data collection was complete for the calculations of KT/V and Ccr using five different methods.


METHODS
Volume of distribution for urea (V) was estimated by four methods: Watson nomogram, ideal body weight (IBW), actual body weight, and total body surface area. Ccr was determined by five methods: Dialysate Ccr was calculated by creatinine (Cr) uncorrected and corrected for the presence of glucose; urinary Ccr was calculated using urinary Cr alone and the average urinary clearance of urea and Cr; and by the Cockcroft and Gault method.


METHODS
Correlations between KT/V and Ccr.


RESULTS
Sixty-three data sets were collected from 52 CAPD patients. The correlations between weekly KT/V and Ccr normalized to 1.73 m2 body surface area were found to be highly variable from one method to another (r2 = 0.012 -0.494). For obese patients (20% above IBW), KT/V values obtained were more variable using the Watson nomogram compared to the IBW and BSA methods.


CONCLUSIONS
KT/V calculated using the Watson nomogram and the Ccr determined using average of urinary urea and creatinine clearance gave the best correlation (r2 = 0.49).
Low
C L
CL
Albany College of Pharmacy, New York 12208, USA.
Bailie
G R
GR
Rasmussen
R
R
Eisele
G
G
D001824:Body Constitution; D001830:Body Surface Area; D003404:Creatinine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D010531:Peritoneal Dialysis, Continuous Ambulatory; D012189:Retrospective Studies; D014508:Urea / Q000378:metabolism*
D014508:Urea; D003404:Creatinine