Measures of Insulin Resistance as a Screening Tool for Dysglycemia in Patients With Coronary Artery Disease: A Report From the EUROASPIRE V Population

Abstract

OBJECTIVE The optimal screening strategy for dysglycemia (including type 2 diabetes and impaired glucose tolerance) in patients with coronary artery disease (CAD) is debated. We tested the hypothesis that measures of insulin resistance by HOMA indexes may constitute good screening methods. RESEARCH DESIGN AND METHODS Insulin, C-peptide, glycated hemoglobin A1c, and an oral glucose tolerance test (OGTT) were centrally assessed in 3,534 patients with CAD without known dysglycemia from the fifth European Survey of Cardiovascular Disease Prevention and Diabetes (EUROASPIRE V). Three different HOMA indexes were calculated: HOMA of insulin resistance (HOMA-IR), HOMA2 based on insulin (HOMA2-ins), and HOMA2 based on C-peptide (HOMA2-Cpep). Dysglycemia was diagnosed based on the 2-h postload glucose value obtained from the OGTT. Information on study participants was obtained by standardized interviews. The optimal thresholds of the three HOMA indexes for dysglycemia diagnosis were obtained by the maximum value of Youden’s J statistic on receiver operator characteristic curves. Their correlation with clinical parameters was assessed by Spearman coefficients. RESULTS Of 3,534 patients with CAD (mean age 63 years; 25% women), 41% had dysglycemia. Mean insulin, C-peptide, and HOMA indexes were significantly higher in patients with versus without newly detected dysglycemia (all P < 0.0001). Sensitivity and specificity of the three HOMA indexes for the diagnosis of dysglycemia were low, but their correlation with BMI and waist circumference was strong. CONCLUSIONS Screening for dysglycemia in patients with CAD by HOMA-IR, HOMA2-ins, and HOMA2-Cpep had insufficient diagnostic performance to detect dysglycemia with reference to the yield of an OGTT, which should still be prioritized despite its practical drawbacks.