Cardiac outcomes after myocardial infarction in elderly patients with diabetes mellitus.

OBJECTIVES To examine the association between (1) comorbid conditions related to diabetes mellitus, clinical findings on arrival at the hospital, and characteristics of the myocardial infarction and (2) risk of heart failure, recurrent myocardial infarction, and mortality in the year after myocardial infarction in elderly 30-day survivors of myocardial infarction who had non-insulin- or insulin-treated diabetes. METHODS Medical records for June 1, 1992, through February 28, 1993, of Medicare beneficiaries (n = 1698), 65 years or older, hospitalizedfor acute myocardial infarction in Connecticut were reviewed by trained abstractors. RESULTS One year after myocardial infarction, elderly patients with non-insulin- and insulin-treated diabetes mellitus had significantly greater risk for readmission for heart failure and recurrent myocardial infarction than did patients without diabetes mellitus, and risk was greater in patients treated with insulin than in patients not treated with insulin. Diabetes mellitus, comorbid conditions related to diabetes mellitus, clinical findings on arrival, and characteristics of the myocardial infarction, specifically measures of ventricular function, were important predictors of these outcomes. Mortality was greater in patients not treated with insulin than in patients treated with insulin; the increased risk was mostly due to comorbid conditions related to diabetes mellitus and poorer ventricular function. CONCLUSIONS Risk of heart failure, recurrent myocardial infarction, and mortality is elevated in elderly patients who have non-insulin- or insulin-treated diabetes mellitus. Comorbid conditions related to diabetes mellitus and ventricular function at the time of the index myocardial infarction are important contributors to poorer outcomes in patients with diabetes mellitus.