HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Demirovic, J. A. Articles by Pai, M. P. Search for Related Content PubMed PubMed Citation Articles by Demirovic, J. A. Articles by Pai, M. P.

JASMINA A. DEMIROVIC, PHARM.D., is Infectious Diseases Pharmacotherapy Resident, College of Pharmacy, University of New Mexico (UNM), Albuquerque. AMY BARTON PAI, PHARM.D., BCPS, FASN, is Associate Professor, Department of Pharmacy Practice, Albany College of Pharmacy and Health Sciences, Albany, NY; at the time of writing she was Associate Professor of Pharmacy and Nephrology, College of Pharmacy, UNM. MANJUNATH P. PAI, PHARM.D., is Scientist, Translational Medicine, Institute for Clinical Pharmacodynamics, Ordway Research Institute, Latham, NY; at the time of writing he was Associate Professor, College of Pharmacy, UNM.

Address correspondence to Dr. Manjunath P. Pai at the Institute for Clinical Pharmacodynamics, Ordway Research Institute, 43 British American Boulevard, Latham, NY 12186 (apai-icpd{at}ordwayresearch.com).

Purpose. Estimates of creatinine clearance (CLcr) based on equations and various body-size descriptors were compared with 24-hour measured CLcr values in morbidly obese patients. Methods. Patients age 18–75 years with a body mass index (BMI) of 40 kg/m2 with stable serum creatinine values were enrolled. Covariates known to contribute to alteration in CLcr were used to exclude patients. Twenty-four-hour urine collection was performed to measure CLcr. Bioelectric impedance analysis was used to estimate fat-free weight (FFW). Glomerular filtration rate was estimated using the four-variable Modification of Diet in Renal Disease (MDRD4) equation. CLcr was estimated using the Cockcroft–Gault and Salazar–Corcoran methods using total body weight (TBW). Body-size descriptors, such as ideal body weight (IBW), adjusted body weight (ABW), and lean body weight (LBW), and FFW were substituted in the Cockcroft–Gault equation to generate additional estimates of CLcr. Results. Fifty-four patients (mean ± S.D. age, 48.4 ± 12.9 years; TBW, 142.3 ± 41.7 kg; BMI, 50.5 ± 12.6 kg/m2) completed the study. All three equations were biased in their estimation of CLcr. Use of MDRD4 and IBW in the Cockcroft–Gault equation underestimated CLcr, while the Salazar–Corcoran equation and use of TBW or ABW in the Cockcroft–Gault equation overestimated this value. Substitution of fat-free weight or LBW in the Cockcroft–Gault equation provided unbiased estimates of CLcr. Conclusion. An LBW estimate, based on TBW and BMI, incorporated into the Cockcroft–Gault equation provided an unbiased, relatively precise, accurate, and clinically practical estimate of 24-hour measured CLcr in morbidly obese patients. Index terms: Calculations; Creatinine; Methodology; Obesity; Weight