Diabetes and Long-Term Survival After Acute Myocardial Infarction:
Comparability of Risk with Prior Myocardial Infarction
Some, but not all, recent studies have found that diabetes is independently associated with long-term mortality following hospitalization for acute myocardial infarction. These studies have also failed to control for certain possible confounding factors, such as alcohol use, physical exertion, and socioeconomic status. In the Determinants of Myocardial Infarction Onset Study, trained interviewers performed chart reviews and face-to-face interviews with 1935 patients hospitalized with acute myocardial infarction between 1989 and 1993. We used Cox proportional hazards regression to determine the effect of diabetes on long-term survival after adjustment for sociodemographic characteristics, medical history, and acute infarct-related complications. Of the 1935 patients, 320 (17%) died during a median follow-up of 3.8 years. Diabetes was associated with higher total mortality in adjusted analyses (hazard ratio 1.6; 95% confidence interval, 1.3-2.1). The magnitude of the effect of diabetes was identical to that of a previous myocardial infarction. The effect of diabetes was not significantly modified by age, smoking, household income, use of thrombolytic therapy, type of hypoglycemic treatment, or duration of diagnosed diabetes, but the mortality risk associated with diabetes was higher among women than among men (adjusted hazard ratios 2.8 versus 1.3; p=0.02). In summary, diabetes is independently associated with increased mortality following acute myocardial infarction, particularly among women. The increase in risk is of the same magnitude as a previous myocardial infarction and provides further support for aggressive treatment of coronary risk factors among diabetic patients.