The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation is less accurate in patients with Type 2 diabetes when compared with healthy individuals

P>Aims To analyse the performances of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and of Modification of Diet in Renal Disease (MDRD) study equations to estimate glomerular filtration rate (GFR) in patients with Type 2 diabetes mellitus with GFRs > 60 ml/min and in healthy volunteers. Methods This cross-sectional study included 111 individuals (56 patients with Type 2 diabetes and 55 healthy volunteers), aged 58 +/- 9 years; 54 individuals were men (49%) and ninety-eight (88%) were white. Glomerular filtration rate was measured by the 51Cr-EDTA single-injection method (51Cr-GFR) and estimated according to the standardized MDRD and CKD-EPI equations. Serum creatinine was measured by a traceable Jaffe method. Bland-Altman analysis was used to examine the agreement between measured and estimated GFR. Bias, accuracy and precision were evaluated. Results In diabetic individuals, 51Cr-GFR was 106 +/- 27 ml/min/1.73 m2, CKD-EPI-estimated GFR 82 +/- 18 ml/min/1.73 m2 and MDRD-estimated GFR 80 +/- 21 ml/min/1.73 m2 (P < 0.001). In healthy volunteers, the corresponding values were 98 +/- 20, 89 +/- 13 and 84 +/- 14 ml/min/1.73 m2 (P < 0.001). The accuracy of CKD-EPI (P30) was higher in healthy volunteers than in diabetic patients (90 vs. 66%, respectively, P < 0.001). The MDRD equation performed as poorly as the CKD-EPI equation in individuals with Type 2 diabetes. Conclusions The CKD-EPI equation is less accurate in patients with Type 2 diabetes when compared with healthy individuals, with a 2.5-fold greater bias.