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 were admitted with a diagnosis of acute 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.

Factors that influence outcome in diabetic subjects with myocardial infarction.

OBJECTIVE: To compare the outcome of acute myocardial infarction in NIDDM patients and nondiabetic control subjects. The relation of glycemic control, duration of diabetes, and major diabetic complications to the outcome of acute myocardial infarction in diabetic subjects was investigated. RESEARCH DESIGN AND METHODS: This was a prospective, hospital-based, case-control study. RESULTS: One hundred and ninety-six NIDDM patients and 196 nondiabetic control subjects with acute myocardial infarction were entered into the study. 23.5% of diabetic subjects and 34.2% of control subjects received thrombolytic therapy (P < 0.05). Diabetic subjects showed signs of reperfusion less often than control subjects (P < 0.05). Mortality was higher in the diabetic group (17.3 vs. 10.2%, P < 0.05). Pump failure (38.3 vs. 16.8%, P < 0.01) and cardiogenic shock (9.7 vs. 3.6%, P < 0.05) also occurred more frequently in diabetic subjects. Loss of heart rate variability was correlated with both pump failure and mortality; proliferative retinopathy was correlated with pump failure. Glycemic control and other diabetic complications did not correlate with outcome. CONCLUSIONS: Our findings confirm the higher mortality and incidence of pump failure in acute myocardial infarction with co-morbid diabetes. They suggest that the less frequent use of thrombolytic therapy, lower reperfusion rates, and more advanced coronary artery disease might be contributory. The presence of autonomic neuropathy and microvascular disease probably also contribute to poor outcome; other major diabetic complications and diabetic control did not influence outcome.