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PRACTICE: Prabir Kumar Mitra, Peter R W Tasker, and M S Ell Chronic kidney disease BMJ 2007; 334: 1273 [Full text]

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eGFR: MDRD Formula has its limitations

Shirwan A. Mirza, MD, FACP, FACE   (18 June 2007)

eGFR: MDRD Formula has its limitations 18 June 2007
Shirwan A. Mirza, MD, FACP, FACE, Clinical Assistant Professor Auburn, New York, USA Send response to journal: Re: eGFR: MDRD Formula has its limitations	In their 10-minute consultation on Chronic kidney disease (CKD), Drs. Mitra, et al outline the utility of eGFR. They assert that eGFR, a number that is based on the "modification of diet in renal disease" [MDRD] formula, determines the stage of CKD. However, the MDRD formula relies solely on serum creatinine taking into account age, gender and ethnicity. Since serum creatinine excretion declines in the elderly and is determined by a person’s size and muscle mass, eGFR based on MDRD formula cannot be reliable for the elderly or at the early stages of CKD.This tool is good when the GFR is > 60, but less precise for GFR < 60. There are recent calls to incorporate cystatin C as a measure for renal function.Despite these limitations, eGFR is considered more reliable than Cockcroft-Gault equation. Reference: Poggio ED, et al Performance of the modification of diet in renal disease and Cockcroft-Gault equations in the estimation of GFR in health and chronic kidney disease. Am J Soc nephrol 2005; 16:459-66 Competing interests: None declared