IMPAIRED GLUCOSE-TOLERANCE IS NORMALIZED BY TREATMENT WITH THE THIAZOLIDINEDIONE TROGLITAZONE

OBJECTIVE - The primary purpose of this study was to assess the effect s of 12 weeks of treatment with either troglitazone, an investigationa l thiazolidinedione that acts as an insulin-action enhancer, or placeb o in patients with impaired glucose tolerance (IGT). RESEARCH DESIGN A ND METHODS - A total of 51 subjects with IGT between 24 and 77 years o f age were enrolled in this multicenter, double-blind, placebo-control led, parallel group study (troglitazone, 25 patients; placebo, 26 pati ents). Patients were randomly assigned to receive either 400 mg trogli tazone (every morning [QAM]) or placebo (QAM). The main outcome measur e was the oral glucose tolerance test (OGTT) assessing glucose, insuli n, and C-peptide levels in the fasting state and every 30 min up to 2 h after ingesting the glucose load. Fasting serum levels of HbA(1c), f ructosamine, lipids, and blood pressure were also measured. RESULTS - A total of 46 patients completed the study The glucose, insulin, and C -peptide responses after a glucose load were significantly reduced at 6 and 12 weeks in the troglitazone treatment group. After 6 weeks of t reatment, 75% (n = 18) of those taking troglitazone had improved to no rmal glucose tolerance, whereas only 38% (n = 9) of those on placebo s howed improvement (P = 0.008). After 12 weeks of treatment, 80% (n = 1 6) of the troglitazone treatment group had normalized their glucose to lerance, while only 48% (n = 10) of those on placebo had converted to normal (P = 0.016). Fasting triglyceride levels in the troglitazone tr eatment group had decreased by 40 mg/dl (0.45 mmol/l) (P = 0.0016). Ot her lipid measurements, blood pressure, glycosylated hemoglobin, and f ructosamine were normal at baseline for both treatment groups and rema ined normal throughout the study CONCLUSIONS - The glycemic response a fter a glucose load is statistically and clinically significantly impr oved for patients with IGT treated with troglitazone.