How to predict carboplatin clearance from standard morphological and biological characteristics in obese patients.
BACKGROUND
We previously proposed a formula to predict carboplatin clearance (CL) from four patient characteristics: plasma creatinine level, body weight, age, and sex (J Natl Cancer Inst 1995; 87: 573). Its accuracy was studied in a subpopulation of obese patients.


METHODS
Twenty-five patients (16 male and 9 female, 23 to 82 years old) were studied. They were 20% to 67% (median 36%) over the ideal weight which was calculated according to the Lorentz equation. Their actual CL was obtained individually by the Siphar program. The pharmacokinetic population program NONMEM was used to determine the best value of substitution for weight in the formula.


RESULTS
By using the actual weight, CL was significantly over predicted (by more than 20% for 7 of 25 patients). By using the mean value between the ideal and the actual weight, a good prediction of CL was obtained: the percentage of error ranged from -21% to +22%.


CONCLUSIONS
The formula is applicable to obese patients if both ideal and actual weights are taken into account.
Bénézet
S
S
Centre Claudius Regaud, Toulouse, France.
Guimbaud
R
R
Chatelut
E
E
Chevreau
C
C
Bugat
R
R
Canal
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D000970:Antineoplastic Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001835:Body Weight / Q000502:physiology; D016190:Carboplatin / Q000493:pharmacokinetics* / Q000627:therapeutic use; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy / Q000378:metabolism; D009765:Obesity / Q000378:metabolism*; D011237:Predictive Value of Tests; D012737:Sex Factors
D000970:Antineoplastic Agents; D003404:Creatinine; D016190:Carboplatin