Influence of Body Weight on the Performance of Glomerular Filtration Rate Estimators in Subjects With Type 2 Diabetes
- Richard A. Chudleigh, MRCP1,
- Gareth Dunseath, MPHIL1,
- Rajesh Peter, MRCP1,
- John N. Harvey, MD, FRCP2,
- Richard L. Ollerton, PHD3,
- Steve Luzio, MD1 and
- David R. Owens, MD, FRCP1
- 1Diabetes Research Unit, Llandough Hospital, Penarth, Cardiff, U.K
- 2Wrexham Maelor Hospital, Wrexham, North Wales, U.K
- 3School of Computing and Mathematics, University of Western Sydney, Sydney, Australia
- Address correspondence and reprint requests to Richard Chudleigh, 20 Llewelyn Goch, Parc Rhydlafar, St. Fagans, Cardiff, U.K. CF5 6HR. E-mail: rachudleigh{at}hotmail.com
- BSA, body surface area
- eGFR, estimated glomerular filtration rate
- GFR, glomerular filtration rate
- MDRD, Modification of Diet in Renal Disease
The American Diabetes Association recommends estimation of glomerular filtration rate (GFR) (1) by either the Cockcroft-Gault (2) or the Modification of Diet in Renal Disease (MDRD) (3) equation in all patients with diabetes. The implication is that these equations provide similar results. Body weight is a numerator in the Cockcroft-Gault equation; however, it is absent from the MDRD equation. This may explain some of the difference in the ability of these equations to estimate GFR in patients with type 2 diabetes, over 80% of whom are obese (4), and may lead to discrepancies in reporting of chronic kidney disease stage (5). Our study was designed to identify whether body weight may explain variability in performance between the Cockcroft-Gault and MDRD equations in patients newly diagnosed with type 2 diabetes.
RESEARCH DESIGN AND METHODS—
The study population consisted of 293 subjects newly diagnosed with type 2 diabetes; 96% were Caucasian and the remainder of South Asian origin. No African-American subjects were included.
Following an overnight fast, anthropometric and biochemical measurements were made. Subjects were intravenously cannulated, and 1 MBq 51Cr-EDTA was administered at 0 min, with further blood sampling at 44, 120, 180, and 240 min.
The 51Cr-EDTA plasma clearance method for GFR measurement, corrected for body surface area (BSA), has been validated previously (6 …
