NDT Advance Access originally published online on March 6, 2006
Nephrology Dialysis Transplantation 2006 21(5):1443-1444; doi:10.1093/ndt/gfl056
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Glomerular filtration rate prediction using lean mass is unsuccessful in diabetic subjects
Email: vincent.rigalleau{at}wanadoo.frSir,
Taylor et al. [1] recently reported that glomerular filtration rate (GFR) could be accurately predicted from lean body mass (LM) assessed by DEXA and serum creatinine, using a simple formula. The first cause of renal insufficiency is diabetes, and we have reported that the usual predictive formulas, such as the MDRD equation and the Cockcroft–Gault formula, give an imperfect prediction of GFR in diabetic patients [2], so we tested to see whether Taylor's equation gave better results.
In 54 diabetic subjects (age: 65±11 years, BMI: 26.5±4.5, 68.5% males, 24.1% with type 1 diabetes) with a wide range of renal function (serum creatinine: 1.05–4.20 mg/dl), we measured GFR (51Cr-EDTA clearance) and LM (by DEXA), and we compared GFR results to their predictions, by correlation studies and paired t-tests.
In nine subjects with serum creatinine (Scr) higher than 3.2 mg/dl, the proposed formula led to a negative result (–11±33 ml/min). This was expected because the formula is:
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The second part of the formula increases with Scr and the predicted GFR becomes null when Scr reaches 3.2 mg/dl.
For the 45 remaining subjects (mean GFR: 39±18 ml/min/1.73 m2), the predicted GFR, indexed on body surface area, are given in Table 1.
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It seems logical to develop predictive formulas, better than for the Cockcroft formula that take account of the creatinine producing tissue mass and the correlation coefficient with measured GFR. A simple equation predicting GFR from Scr and LM, that can be correctly assessed in renal insufficient patients without DEXA, simply from anthropometrics or body impedance analysis [3], would constitute important progress for practice. However, the relationships between LM and creatinine production, and between Scr and glomerular filtration, are not simple. The formula proposed by Taylor et al. [1] leads to an important overestimation of GFR for our diabetic patients. As mentioned by the authors, further work is also needed to validate this formula on a higher number of non-diabetic subjects, with Scr lower than 3.2 mg/dl.
Conflict of interest statement. None declared.
Université de Bordeaux 2—Victor Segalen 33000 Bordeaux France1 Nutrition-Diabétologie Hôpital Haut-Lévêque Avenue de Magellan, 33600 Pessac France2 Néphrologie3 Médecine Nucléaire Hôpital Pellegrin Place Amélie Raba-Léon 33000 Bordeaux, France
References
- Taylor TP, Wang W, Shrayyef MZ, Cheek D, Hutchison FN, Gadegbeku CA. Glomerular filtration rate can be accurately predicted using lean mass measured by dual-energy X-ray absorptiometry. Nephrol Dial Transplant 2006; 21: 84–87
[Abstract/Free Full Text] - Rigalleau V, Lasseur C, Perlemoine C et al. Estimation of glomerular filtration rate in diabetic subjects, Cockcroft or MDRD formula? Diabetes Care 2005; 28: 838–843
[Abstract/Free Full Text] - Rigalleau V, Lasseur C, Chauveau P et al. Body composition in diabetic subjects with chronic kidney disease: interest of bio-impedance analysis, and anthropometry. Ann Nutr Metab 2005; 48: 409–413[CrossRef]
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