Measures of insulin resistance as a screening tool for dysglycaemia in patients with coronary artery disease A report from the EUROASPIRE V population
Objective The optimal screening strategy for dysglycaemia (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 homeostasis model assessment (HOMA) indexes may constitute good screening methods.
Research Design and Methods Insulin, C-peptide, glycated haemoglobin A1c (HbA1c) and an oral glucose tolerance test (OGTT) were centrally assessed in 3534 CAD patients without known dysglycaemia from the EUROASPIRE V survey. Three different HOMA indexes were calculated: HOMA-IR, HOMA2 based on insulin (HOMA2-ins), and HOMA2 based on C-peptide (HOMA2-Cpep). Dysglycaemia was diagnosed based on the two-hour postload glucose value obtained from the OGTT. Information on study participants was obtained by standardised interviews. The optimal thresholds of the three HOMA indexes for dysglycaemia diagnosis were obtained by the maximum value of Youden’s J statistic on receiver operator characteristics curves. Their correlation with clinical parameters was assessed by Spearman’s coefficients.
Results Of 3534 CAD patients (mean age 63 years, 25% women), 41% had dysglycaemia. Mean insulin, C-peptide and HOMA indexes were significantly higher in patients with vs. without newly detected dysglycaemia (all p<0.0001). Sensitivity and specificity of the three HOMA indexes for the diagnosis of dysglycaemia were low, but their correlation with body mass index and waist circumference was strong.
Conclusions Screening for dysglycaemia in CAD patients by HOMA-IR, HOMA2-ins and HOMA2-Cpep had insufficient diagnostic performance to detect dysglycaemia with reference to the yield of an OGTT, which should still be prioritized despite its practical drawbacks.