Relation of New and Old Formulas for Estimating Creatinine Clearance among Stroke Survivors

Abstract

Objective: To assess whether the newly proposed formula for estimating glomerular filtration function (GFR) – the Chronic Kidney Disease Epidemiology (CKD-EPI) equation – would be materially distinct from the established Modification of Diet in Renal Disease (MDRD) equation in diagnosing chronic kidney disease (CKD) among US stroke survivors. Materials and Methods: Data from the National Health and Nutrition Examination Survey from 1999–2004, a nationally representative sample of adults from the United States, were used to assess the correlation between the MDRD and CKD-EPI equations among persons aged ≧55 years who had experienced a prior stroke. CKD was defined as GFR <60 ml/min/1.73 m². Results: Among 6,382 adults, 5,321 (83%) had full and complete data. With MDRD, 20.4% of the sample had CKD vs. 19.4% using the CKD-EPI. There was 97.7% agreement between MDRD and CKD-EPI using the 60 ml/min/ 1.73 m² cutoff point. The correlation between both equations was extremely high (r = 0.954). Conclusion: The newly developed CKD-EPI equation is very highly correlated to the more established MDRD formula and does not materially change CKD diagnosis made by the latter among persons with a history of stroke.