Diabetes, Insulin Resistance, and the Metabolic Syndrome in Patients With Acute Myocardial Infarction Without Previously Known Diabetes

Abstract

OBJECTIVE—Individuals with diabetes have an increased morbidity from acute myocardial infarction (AMI). Based on an oral glucose tolerance test (OGTT), 40–45% of patients with AMI have diabetes. The objective of this study was to characterize the glucometabolic profile of patients with AMI without known diabetes and to see if sustained glucometabolic perturbations are predictable during the hospital phase of the disease. RESEARCH DESIGN AND METHODS—A total of 145 patients with AMI and no previous diagnosis of diabetes were subjected to an OGTT at hospital discharge and 3 months thereafter. Based on the OGTT after 3 months, they were defined as having normal glucose tolerance (NGT; n = 50), impaired glucose tolerance (IGT; n = 59), or diabetes (n = 36). Components of the metabolic syndrome, including insulin resistance assessed by homeostasis model assessment (HOMA-IR), were recorded. RESULTS—Patients with AMI had no changes in insulin resistance from hospital discharge to follow-up. An OGTT and/or a single blood glucose taken 60 min (BG-60) after ingestion of 75 g glucose at hospital discharge were predictors of the outcome of the OGTT at follow-up. With a cutoff value for BG-60 of 8.6 mmol/l, 70% of the patients were correctly predicted as either belonging to the NGT group or the IGT/diabetes group after 3 months. Age, BMI, antihypertensive treatment, HbA1c, fasting blood glucose, blood lipids, insulin, proinsulin, HOMA-IR, and plasminogen activator inhibitor 1 did not add predictive power. CONCLUSIONS—Patients with AMI and no previous diagnosis of diabetes have no changes in insulin resistance from hospital discharge to a 3-month follow-up. An OGTT or a single BG-60 performed at hospital discharge predicts the diagnosis of IGT or diabetes 3 months thereafter.