Do differences in baseline characteristics or in management account for the poorer in-hospital and subsequent outcome after myocardial infarction in diabetics?

Objective -There is an excess mortality after myocardial infarction in diabetics, but also documented significant differences in the characteristics of MI and in management between diabetics and non-diabetics. The aim of this prospective study in a large unselected patient cohort in a single French region was to determine if baseline characteristics, management, or in-hospital and one-year mortality differed in diabetic and non-diabetic patients with myocardial infarction. Methods and results - Data were prospectively collected in consecutive patients with myocardial infarction admitted to all hospitals in three departments in the Rhone-Alpes region between September 1, 1993 and January 3 1,1995. Among the 2,297 patients, 4 10 patients (17.8%) were diabetic. Although diabetics were older than non-diabetics (70.3 vs. 67.8 years; p < 0.0004), and less likely to receive thrombolysis (31% vs. 36%; p = 0.043), in-hospital mortality was not significantly higher (17.3% vs. 14.7%) than in non-diabetics. In multivariate analysis, diabetes was a significant predictor of one-year mortality (relative risk: 1.41; 95% CI = 1.10 - 1.79; p = 0.0063) but not of in-hospital mortality (relative risk: 1.2; 95% CI = 0.9 - 1.7; p = 0.25). Multivariate predictors of in-hospital and one-year mortality in diabetics were age and Killip class at admission. Conclusions - In this large unselected French cohort, diabetes mellitus was a significant predictor of one-year but not of in-hospital mortality after myocardial infarction in a French region. This negative effect of diabetes on mortality was not related to differences in baseline characteristics, or in initial or post-discharge management between diabetics and non-diabetics.