Prognosis following first acute myocardial infarction in Type 2 diabetes: a comparative population study

To estimate the incidence of death and macrovascular complications after a first myocardial infarction for patients with Type 2 diabetes.

In a retrospective, incidence cohort study in the Tayside Region of Scotland we studied all patients hospitalized with a diagnosis of first acute myocardial infarction from 1 April 1993 to 31 December 1994. The primary endpoint was time to death. Secondary endpoints were 2-year incidence of hospital admission for angina, myocardial infarction, stroke, heart failure, coronary angiography, coronary artery bypass graft (CABG) and percutaneous transluminal coronary angioplasty (PTCA).

The 147 patients with Type 2 diabetes had significantly worse survival with an increase in relative hazard of 67% compared with non-diabetic patients. After adjustment for age, sex, smoking status, prior heart failure, prior angina, delay to hospitalization, site of infarction, drug therapy with aspirin, beta-blockers, streptokinase and hyperlipidaemia and treated hypertension, Type 2 diabetes was still associated with a 40% higher death rate compared with people without diabetes (P < 0.05) There was no significant difference in death rates in those aged over 70 years, but an indication of a trend in younger individuals with a four-fold increase in death rate in those with diabetes aged < 60 years, compared with a rate ratio of 2.6 in those with diabetes aged 61-70 years.

Among hospitalized patients with first acute myocardial infarction, Type 2 diabetes mellitus is consistently associated with increased mortality and increased hospital admission for heart failure. The estimated 4-year survival rate is only 50%. Our results indicate that younger subjects with Type 2 diabetes and acute myocardial infarction are a high-risk group deserving of special study, and support the argument for aggressive targeting of coronary risk factors among patients with Type 2 diabetes.