Evolution of insulin resistance in coronary artery disease patients on four different pharmacological therapies

The objective of the study was to examine the evolution of insulin sensitiv ity in a group of patients with stable coronary artery disease receiving on e of four different pharmacological therapies. Insulin sensitivity was eval uated using an insulin suppression test in 40 newly diagnosed patients with coronary artery disease and no previous history of metabolic disorders, wh o were not taking any medication which might affect insulin sensitivity. Th e insulin suppression test consisted of a constant infusion of glucose, ins ulin and somatostatin for 150 min; insulin resistance was estimated by dete rmining the steady-state plasma glucose concentrations during the last 60 m inutes of the test. The insulin sensitivity index was calculated by the for mula: insulin sensitivity index = (glucose infusion rate/steady state plasm a glucose concentrations) x 10(3). A second insulin suppression test was pe rformed after 6 months' therapy with either isosorbide mononitrate, atenolo l, diltiazem or captopril in 30 of the 40 patients. There were no differences between any of the groups before therapy was init iated. After 6 months, patients treated with captopril and, to a lesser ext ent, those treated with diltiazem showed statistically significantly decrea sed steady state plasma glucose concentrations and increased insulin sensit ivity index compared to basal values. No statistically significant differen ces were found in the other two groups. We conclude that captopril and, to a lesser extent, diltiazem improve insulin sensitivity in patients with sta ble coronary artery disease.