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 sensitivity in a group of patients with stable coronary artery disease receiving one of four different pharmacological therapies. Insulin sensitivity was evaluated using an insulin suppression test in 40 newly diagnosed patients with coronary artery disease and no previous history of metabolic disorders, who were not taking any medication which might affect insulin sensitivity. The insulin suppression test consisted of a constant infusion of glucose, insulin and somatostatin for 150 min; insulin resistance was estimated by determining the steady-state plasma glucose concentrations during the last 60 minutes of the test. The insulin sensitivity index was calculated by the formula: insulin sensitivity index = (glucose infusion rate/steady state plasma glucose concentrations) x 10(3). A second insulin suppression test was performed after 6 months' therapy with either isosorbide mononitrate, atenolol, diltiazem or captopril in 30 of the 40 patients. There were no differences between any of the groups before therapy was initiated. After 6 months, patients treated with captopril and, to a lesser extent, those treated with diltiazem showed statistically significantly decreased steady state plasma glucose concentrations and increased insulin sensitivity index compared to basal values. No statistically significant differences were found in the other two groups. We conclude that captopril and, to a lesser extent, diltiazem improve insulin sensitivity in patients with stable coronary artery disease.

Relationship between insulin sensitivity and dehydroepiandrosterone sulfate in patients with ischemic heart disease

Insulin resistance has been related to the pathogenesis and development of ischemic heart disease (IHD). Dehydroepiandrosterone sulfate (DHEA-S) has been suggested as the possible link between these two entities. The aim of this study was to clarify the relationship between insulin resistance and DHEA-S in patients with IHD. Thirty-two male patients with newly-diagnosed IHD and without known metabolic disorders and 11 healthy matched controls were included in this study. Insulin sensitivity was assessed by an insulin suppression test, and DHEA-S levels were measured before the test (basal) and at the end of the test (during hyperinsulinemia). Insulin resistance, defined as an insulin sensitivity index (ISI) below the normal range derived from the control group, was present in 78% of IHD patients; they also displayed, as a group, lower ISI (P < 0.0001) than controls. DHEA-S levels were lower in IHD than in controls, both basal and during hyperinsulinemia (P < 0.05). DHEA-S levels decreased when hyperinsulinemia was achieved, both in IHD patients and controls (P < 0.0005). The magnitude of the decrease was the same in both groups. No correlation between ISI and DHEA-S levels was found. In conclusion, insulin sensitivity is lower in patients with IHD, even when major metabolic abnormalities associated with insulin resistance are excluded. These patients also show decreased DHEA-S levels, which are further reduced when acute induced hyperinsulinemia is achieved, although, as the decline was similar to that of controls, there does not seem to be resistance to this particular action of insulin.