Troglitazone use in insulin-treated type 2 diabetic patients

OBJECTIVE - To determine the ability of troglitazone to reduce requirements for injected insulin while maintaining blood glucose levels in insulin-treated patients with type 2 diabetes. RESEARCH DESIGN AND METHODS - This 26-week double-blind study with open-label extension included patients who had failed previous oral antidiabetic medication and took greater than or equal to 30 but <150 U of insulin daily. The 222 patients in the double-blind study received 200 or 400 mg troglitazone once daily or matching placebo. The primary end point was the proportion of patients meeting the target of greater than or equal to 50% reduction in injected insulin and either a 15% reduction in fasting blood glucose or a blood glucose <7.8 mmol/l. Insulin dose was reduced 25% based on a study-specific algorithm whenever fasting blood glucose was reduced 5% from baseline. Also of interest were changes in insulin dose and HbA(1c). The open-label extension included 173 patients. They received 200 mg of troglitazone with optional titration to 400 mg, and insulin dose was adjusted based on investigators' standards of care. Open-label measures were change in insulin dose, HbA(1c), and fasting serum glucose (FSG). RESULTS - In the double-blind phase, 22 and 27% of the 200- and 400-mg troglitazone groups, respectively, reached target, compared with placebo (7%) (P < 0.01). Insulin dose reductions of 13 +/- 3, 30 +/- 3, and 41 +/- 3 U were observed for placebo, 200-, and 400-mg trogli tazone groups, respectively. HbA(1c) decreased 0.09 +/- 0.14% for placebo, 0.13 +/- 0.14% for 200 mg, and 0.41 +/- 0.14% for 400 mg (P < 0.05) troglitazone. In the open-label extension, troglitazone treatment resulted in >50% reduction from baseline in daily insulin dose and decreases in HbA(1c) of 1% and in FSG of >17%. CONCLUSIONS - Troglitazone decreases daily injected insulin dose requirements and improves glycemic control in insulin-treated patients with type 2 diabetes.