Estimating glomerular filtration rate (GFR) in diabetes: the performance of MDRD and CKD-EPI equations in patients with various degrees of albuminuria.

OBJECTIVES: The aim of this study was to compare the performance of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease Study (MDRD) equations in estimating GFR in a large cohort of diabetic patients with various degrees of albuminuria. DESIGN AND METHODS: In a group of 842 diabetic patients GFR was estimated from standardized creatinine, with MDRD-Study and CKD-EPI equations, and their performance evaluated regarding clinical stages of albuminuria and chronic kidney disease (CKD).
RESULTS: Patients with normoalbuminuria had higher eGFR when calculated by CKD-EPI, than MDRD-Study equation [median (IQR): 103 (91-115) vs 97 (85-113)mL/min/1.73 m(2), P=0.006, n=364], which significantly influenced the prevalence of stage 1 CKD [eGFR>90 mL/min/1.73 m(2): 76.7% (CKD-EPI) vs. 65.1% (MDRD-Study), P=0.005]. There were no differences between the eGFR values derived by two equations in patients with micro- and macroalbuminuria, and more advanced staging of CKD.
CONCLUSION: CKD-EPI equation might be a superior surrogate marker of GFR in patients with normoalbuminuria and hyperfiltration and could be used as a screening tool for early renal impairment in diabetes. It's validity as a marker of progression of diabetic nephropathy merits further investigation.