Evaluation of glomerular filtration rate estimation by Cockcroft–Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae in oncology patients

Abstract

The aim was to evaluate the accuracy of Cockcroft-Gault, Jelliffe, Wright and Modification of Diet in Renal Disease (MDRD) formulae as a substitute for the gold standard measure of glomerular filtration rate (GFR) using chromium 51 EDTA. Retrospective analysis of GFR measurements in oncology patients from a University Teaching Hospital over 3 years was carried out. Bias and precision of estimates of GFR were compared with measured GFR. Six hundred and sixty patients with measured GFR (median 90 ml/min, range 23-179 ml/min) were identified. Cockcroft-Gault produced the smallest bias (median percentage error -1.4%) and highest precision (median absolute percentage error 14.0%) and was the most accurate for carboplatin dosing. For patients>30% over their ideal body weight (IBW), using IBW+30% in the Cockcroft-Gault formula was more precise than using actual body weight or IBW. The Wright formula was most accurate for patients aged 70+years and patients with a body mass index (BMI)≥30 but overestimated GFR when GFR<50 ml/min. When measured GFR is unavailable, we advise estimating GFR using the Cockcroft-Gault formula and using IBW+30% for patients weighing>30% over their IBW. If the GFR is ≥50 ml/min and the patient is >70 years and/or BMI≥30, the Wright formula gives the best estimate of GFR.