ABSENCE OF CIRCADIAN VARIATION IN THE ONSET OF ACUTE MYOCARDIAL-INFARCTION IN DIABETIC SUBJECTS

Objectives-To investigate the circadian pattern of acute myocardial infarction in non-insulin-dependent diabetic patients and to compare it with that of controls. Background-Previous studies have shown that there is a circadian variation in the incidence of acute myocardial infarction, but there are few data on diabetic subjects. Methods-A hospital based prospective case-control study. Results-196 diabetic patients and 196 age and sex matched controls admitted with a diagnosis of myocardial infarction during the study period. In 32 diabetic patients and 38 controls, the time of onset of myocardial infarction was unknown; in 34, 44, 42, and 44 diabetic patients the onset was in the first to fourth quarters respectively (chi(2) = 1.66, NS). The corresponding figures for the controls were 30, 56, 45, and 27 (chi(2) = 13.9, P < 0.005). The difference between the two groups was highly significant (chi(2) = 10.3, P < 0.025). Conclusions-Diabetic subjects do not show a significant circadian variation in the onset of acute myocardial infarction.