Prevalence of glucose abnormalities among patients presenting with an acute myocardial infarction

Background Patients with an acute myocardial infarction (AMI) who have glucose abnormalities are at increased risk for death and adverse ischemic outcomes. The contemporary prevalence of glucose abnormalities among AMI patients in the United States, as determined by hemoglobin A1c (HbA1c), is unknown. Methods Patients hospitalized with AMI in a 24-site US AMI registry from 2005 to 2008 were examined for the presence of dysglycemia using HbA1c, which was analyzed at a core laboratory. Patients were categorized by American Diabetes Association guidelines as having diabetes (HbA1c ≥ 6.5%), prediabetes (HbA1c 5.7%-6.4%), or normoglycemia. Baseline demographic, clinical, and metabolic characteristics, as well as long-term all-cause mortality, were compared among groups. Results Among 2,853 patients with AMI, 1,083 (38%) had diabetes, of which 196 (18%) were newly diagnosed. There were an additional 887 patients (31%) with prediabetes and 883 patients (31%) who had normal glucose metabolism. Patients with metabolic abnormalities were older, were more frequently female, and had higher prevalence of cardiac and noncardiac comorbidities, including multivessel disease and left ventricular systolic dysfunction. Patients with increasing metabolic abnormalities had higher mortality over the 3 years after the AMI (8.6% in those with normoglycemia, 10.6% in prediabetes, 11.3% in newly diagnosed diabetes, and 20.3% in known diabetes; log rank P <.001). Conclusions In a large US AMI registry, we found that nearly 7 in 10 patients had dysglycemia, with 38% having diabetes and an additional 31% with prediabetes based on HbA1c levels. Over half of the patients who did not have a known diagnosis of diabetes at the time of admission had either newly diagnosed diabetes or prediabetes. Progressively greater severity of dysglycemia was also associated with incremental increase in long-term mortality. These data highlight the AMI hospitalization as a key opportunity to screen for glucose abnormalities so that appropriate interventions and patient education efforts can be implemented prior to discharge.