Evaluation of Insulin Resistance in Normoglycemic Patients with Coronary Artery Disease

Background: Insulin resistance is clearly associated with coronary artery disease (CAD) in diabetics. Insulin resistance may also be present in normoglycemic individuals, and some of these patients can be diagnosed as having metabolic syndrome (MS) according to various definitions. However, the relationship between hyperinsulinemia and CAD is obscure in normoglycemic individuals, especially in patients who do not meet the criteria for MS. Hypothesis: This study evaluated insulin resistance in normoglycemic patients with CAD, and investigated the association of insulin resistance with inflammation and lipid levels. Methods: Fifty-six CAD patients, and 57 age- and sex-matched controls with normal coronary arteries confirmed by conventional coronary arteries angiography were included in the study. Participants were considered for the diagnosis of MS according to criteria of the National Cholesterol Education Program (NCEPATP III) and the International Diabetes Federation (IDF). Fasting plasma glucose, insulin, lipids, and c-reactive protein (CRP) levels were studied. The homeostasis model assessment insulin resistance index (HOMA IR) was calculated. Results: The ratio of subjects with MS was similar in the 2 groups. Insulin, CRP, low-density lipoprotein (LDL) cholesterol, and HOMA IR were higher in the study group than in the controls. The HOMA IR, LDL cholesterol, and serum CRP levels were determined as predictors of CAD. Conclusion: Our data revealed that insulin resistance and subclinical inflammation are present in normoglycemic patients with CAD. As the proportion of patients with MS was similar in the 2 groups, we suggest that HOMA IR values may provide more sensitive information than MS definitions about the association between insulin resistance and CAD in normoglycemic patients.