Clinical course of myocardial infarction among diabetic patients.

The clinical course of myocardial infarction (MI) was compared between 154 known diabetic (Ds) and nondiabetic (NDs) MI patients matched for age, sex, and hospital ward. In both groups similar numbers of cases with cardiac rupture, shock, pulmonary edema, and clinically observed arrhythmias were found. In contrast, Ds patients had significantly more frequent A-V and intraventricular conduction disorders than NDs (P less than 0.02). Ds also died twice more often from MI (36%) than matched controls (18%). The excess case fatality rates from MI among Ds were limited to the period between the second and seventh day of hospitalization. The excessive fatality of Ds from MI resulted mainly from the high liability of insulin-dependent diabetic patients (IDDs), with the relative risk of over 4 in relation to NDs. Ds with arrhythmias and/or conduction disorders had a particularly poor prognosis for surviving, the relative risk exceeding 3. No ready explanation of this phenomenon is presently available.