INSULIN-RESISTANCE IN PATIENTS WITH A RECENT DIAGNOSIS OF CORONARY-ARTERY DISEASE

Objective To elucidate whether insulin resistance is present in corona ry artery disease (CAD) at diagnosis and to study its relationship wit h other known cardiovascular risk factors. Methods We evaluated the in cidence of insulin resistance in 40 newly diagnosed CAD patients. Fift een healthy subjects were used as a control group. The patients and co ntrols had no previous history of metabolic disorders, and were not be ing administered any medication that might have affected their insulin sensitivity, Immediately after diagnosis of CAD, a standard 75 g oral glucose-tolerance test (OGTT) and an insulin suppression test (IST) w ere performed on separate days, The IST consisted of a constant infusi on of glucose, insulin and somatostatin for 150 min; insulin resistanc e was estimated by determining the steady-state plasma glucose (SSPG) concentrations during the last 60 min of the test, The insulin sensiti vity index (ISI) was calculated by the formula ISI = (glucose infusion rate/SSPG] x 10(3). Results Insulin resistance, defined by an ISI bel ow the normal range derived from the control group, was present in 82. 5% of the CAD patients. As a group, the patients with CAD displayed lo wer ISI (means +/- SD: 29.23 +/- 11.23 versus 50.33 +/- 9.37 dl/kg per min, P < 0.001) and higher SSPG (225 +/- 57 versus 123 +/- 24 mg/dl, P < 0.001) than did controls, Serum triglycerides and uric acid were h igher and high-density lipoprotein cholesterol levels were lower in pa tients than they were in controls, No differences were observed in fas ting plasma insulin, glucose, total and low-density lipoprotein choles terol concentrations. An abnormal OGTT result was observed in 27 patie nts. The ISI was low in 88.8% of the patients with an abnormal OGTT re sult and in 69% of the 13 patients with a normal OGTT result. Conclusi ons Insulin resistance and even impaired glucose tolerance are common findings in CAD at diagnosis, The changes in the lipid profile and in uric acid levels paralleled the changes in insulin sensitivity, These results suggest that insulin resistance might play a role in the devel opment of coronary atherosclerosis and that its early diagnosis might be important in the prophylaxis of CAD.