MYOCARDIAL INFARCT SIZE AND MORTALITY IN PATIENTS WITH NONINSULIN-DEPENDENT DIABETES-MELLITUS

Objectives. To study the infarct size and mortality in patients with non-insulin-dependent diabetes mellitus (NIDDM) and in non-diabetic subjects with their first acute myocardial infarction. Design. Seven year follow-up study of large representative cohorts of patients with non-insulin-dependent diabetes mellitus and non-diabetic subjects (study 1) and the FINMONICA acute myocardial infarction register study in 1988-89 (study 2). Setting. Populations of the districts of the Kuopio University Hospital and Turku University Central Hospital (study 1). Populations of Kuopio and North Karelia provinces and Turku/Loimaa area (study 2). Subjects. Study 1: 1059 patients with non-insulin dependent diabetes mellitus and 1373 non-diabetic subjects aged 45-64 years at baseline; during the follow-up 166 patients with non-insulin-dependent diabetes mellitus (91 men and 75 women) and 30 non-diabetic subjects (25 men and five women) were hospitalized for their first acute myocardial infarction. Study 2: 1622 patients aged 25-64 years hospitalized for their first acute myocardial infarction; 144 patients (90 men and 54 women) had non-insulin-dependent diabetes mellitus and 1153 (890 men and 263 women) were non-diabetic. Main outcome measures. The infarct size was assessed on the basis of maximum levels of serum cardiac enzymes (studies 1 and 2) and QRS-score (study 1). Results. No differences were found in maximum levels of serum cardiac enzymes between diabetic and non-diabetic patients. Similarly ORS-score gave no suggestion of a difference in infarct size between diabetic and non-diabetic patients. In both studies mortality before hospital admission was similar in diabetic and non-diabetic patients, but mortality within 28 days from hospital admission was twice as high in diabetic patients as in non-diabetic patients. Cardiac failure was the main cause of death significantly more often in diabetic patients than in nondiabetic patients (study 2). Conclusions. Poorer prognosis of acute myocardial infarction in diabetic patients appears not to be explained by a larger infarct size but probably by adverse effects of the diabetic state itself on myocardial function.