Long‐term survival after acute myocardial infarction and relation to type 2 diabetes and other risk factors

Abstract

Background: Diabetes mellitus (DM) is well established as a short-term prognostic indicator after myocardial infarction (MI), but little long-term data are available. Hypothesis: The objective of the study was to assess the impact of DM and other patient characteristics at baseline on long-term mortality after acute MI. Methods: Patients who were hospitalized with MI from December 1990 to November 1992 were recruited. Baseline data were recorded and patients were followed up through January 31, 2008, to assess their survival rates. Survival curves were generated by the Kaplan-Meier method. The main outcome measure was long-term survival (median 16.6 y). Results: The study followed 337 patients (mean age 66.4 y, 61.1% men) for a median of 16.6 years. Using Cox regression analysis, survival was associated with history of MI (hazard ratio [HR]: 1.47, P = 0.016), DM at baseline (HR: 1.31, P = 0.038), and age (HR: 1.061 for each additional year, P < 0.001). By multivariable regression, cardiovascular mortality was also associated with previous MI (HR: 1.58, P = 0.017), DM at baseline (HR: 1.69, P = 0.001), and age (HR: 1.075 for each additional year, P < 0.001). There was no statistically significant difference between the HRs for history of MI and history of DM. Conclusions: Diabetic patients with MI have a higher long-term all-cause and cardiovascular mortality. Our data also show that in patients with MI, DM confers the same level of risk as a previous MI. This extends to patients with documented MI, our concept of diabetes being a coronary heart disease equivalent. Based on this and on data from the literature, we propose that it would be more accurate to consider DM as an MI equivalent rather than a coronary heart disease equivalent.