Prognostic abilities of different calculation formulas for the glomerular filtration rate in elderly Chinese patients with coronary artery disease

OBJECTIVE As a standard indicator of renal function, the glomerular filtration rate (GFR) is vital for the prognostic analysis of elderly patients with coronary artery disease (CAD). Thus, the search for the calculation equation of GFR with the best prognostic ability is an important task. The most commonly used Modification of Diet in Renal Disease (MDRD) equation and the Chinese version (CMDRD) of the MDRD equation has many shortcomings. The newly developed Mayo Clinic quadratic (Mayo) and Chronic Kidney Disease (CKD) Epidemiology Collaboration (CKD-EPI) equations may overcome these shortcomings. Because the populations involved in these equation-related studies are almost completely devoid of subjects > 70 years of age, there are more debates on the performance of these equations in the elderly. This study was designed to compare the prognostic abilities of different calculation formulas for the GFR in elderly Chinese patients with CAD. METHODS This study included 1050 patients (≥60 years of age) with CAD. The endpoint was all-cause mortality over a mean follow-up period of 417 days. RESULTS The median age was 86 years (60-104 years). The median values for the MDRD-GFR, CMDRD-GFR, CKD-EPI-GFR, and Mayo-GFR were 66.0, 69.2, 65.6, and 75.8 mL/minute/1.73 m(2), respectively. The prevalence of GFR < 60 mL/minute/1.73 m(2) based on these measures was 39.3%, 35.4%, 43.0%, and 28.7%, respectively. Their area under the curve values for predicting death were 0.611, 0.610, 0.625, and 0.632, respectively. Their cut-off points for predicting death were 54.1, 53.5, 48.0, and 57.4 mL/minute/1.73 m(2), respectively. Compared with the MDRD-GFR, the net reclassification improvement values of the CMDRD-GFR, CKD-EPI-GFR, and Mayo-GFR were 0.02, 0.10, and 0.14, respectively. CONCLUSION The prognostic abilities of the CKD-EPI and Mayo equations were significantly superior to the MDRD and CMDRD equations; the Mayo equation had a mild, but not statistically significant superiority compared with the CKD-EPI equation in elderly Chinese patients with CAD.