Estimating glomerular filtration rate: comparison of the CKD-EPI and MDRD equations in a large UK cohort with particular emphasis on the effect of age

Background: The chronic kidney disease (CKD)-Epidemiology Collaboration (CKD-EPI) equation was developed to address the underestimation of measured glomerular filtration rate (GFR) by the Modification of Diet in Renal Disease (MDRD) equation at levels >60 mL/min/1.73 m2. Aim: To assess the impact of the CKD-EPI equation on the estimation of GFR in a large adult UK population (n = 561 400), particularly looking at the effect of age. Design: Serum creatinine results (ID-MS-aligned enzymatic assay) were extracted from the pathology database during 1 year on adult ( 18 years) patients from primary care. Methods: The first available creatinine result from 174 448 people was used to estimate GFR using both equations and agreement assessed. Results: Median CKD-EPI GFR was significantly higher than median MDRD GFR (82 vs. 76 mL/min/1.73 m2, P 70 years there is very little difference between the equations, and among the very elderly CKD-EPI may actually increase CKD prevalence estimates.