Insulin Response to Oral Glucose in Patients with a Previous Myocardial Infarction and in Patients with Peripheral Vascular Disease: Hyperinsulinism and Its Relationships to Hypertriglyceridemia and Overweight

Abstract

The insulin response to an oral glucose load (100 gm.) in 127 patients with a previous myocardial infarction (MI) (six months to one year) and in 65 patients with surgically treated or arteriographically identified peripheral vascular disease (PVD) was compared with that of 89 controls after matching the three collectives for age, glucose tolerance, and per cent ideal body weight (% IBW). The insulin response was of greater magnitude in MI and PVD groups than in respective control groups also in the absence of hyperglycemia, hypertriglyceridemia, and obesity. This finding suggests that hyperinsulinism may represent an early metabolic alteration associated with the development of MI and PVD. The insulin secretion pattern was prevalently of the delayed type in association with impaired glucose tolerance and with hypertriglyceridemia but not with overweight. Correlations between serum insulin, triglyceride (TG) levels, and % IBW were also investigated. We found a strong correlation (p < 0.001) between stimulated insulin levels and % IBW in MI patients and none in PVD patients; conversely, the correlation between serum insulin and TG levels was very high (p < 0.001) in PVD patients and only weak (p < 0.05) in MI patients. No correlation was found between cholesterol (CH) levels and any of the other parameters studied. According to these results, it seems likely that hyperinsulinism plays a major role as a closely associated factor to obesity in those subjects who develop an MI, whereas in PVD patients the raised insulin levels may favor lipid accumulation in the arterial intima and accelerate the progress of atherosclerosis.