Indexing glomerular filtration rate for body surface area in obese patients is misleading: concept and example

Effects of weight loss on renal function in overweight Japanese men

“…Furthermore, Cockcroft et al 38 assessed the accuracy of the equation to be in around 70% agreement in subjects with normal CCr (normal renal function), although, particularly in patients with a CCr below 50 ml min À1 , overall accuracy of the equation is substantially diminished, because creatinine is removed not only by glomerular filtration but also by renal tubular secretion. 50 Thus, CCr with the Cockcroft-Gault equation may obscure the genuine association between renal function and WL (adiposity) in subjects with normal renal function, 51 although CCr with the Cockcroft-Gault equation in mild-to-moderate renal injury cannot reflect renal functions accurately. In this study all subjects had 480 ml min À1 of CCr without proteinuria or 41.5 mg dl À1 of serum creatinine (normal renal function).…”

Effect of Intrauterine Growth Restriction on Kidney Function at Young Adult Age: The Nord Trøndelag Health (HUNT 2) Study

“…There is controversy about how to index kidney function for body size. 23 Therefore, we used different estimates of kidney function. Creatinine clearance was estimated using the Cockcroft-Gault formula, and glomerular filtration rate (GFR) was estimated using the values to avoid problems with interlaboratory calibration differences, we recalibrated our original Jaffè-based creatinine values to the Roche enzymatic method.…”

“…All analyses were performed separately for men and women, 23 and analyses were repeated with adjustment for maternal risk factors (age, preexisting diabetes and/or kidney disease, and preeclampsia), adult smoking, and educational level. As listed in Table 1, based on the Medical Birth Registry, there were no significant differences in BWs or other obstetric, neonatal, and maternal characteristics between study subjects and nonparticipants in Nord-Trøndelag County.…”

“…23 We therefore used Cockcroft-Gault estimates (milliliters per minute) as our primary outcome, but also used other estimates of kidney function. Especially in men, all outcome variables were consistently associated with BWSDS, indicating that the relation between BW and kidney function probably is not caused by chance finding or bias.…”

eGFR

“…In this regard, the eGFR-MDRD equation provides values normalized to a body surface area of 1.73 m 2 . This correction can be problematic in very obese or very lean individuals (20).…”