The synergistic effect of miglitol plus metformin combination therapy in the treatment of type 2 diabetes.

OBJECTIVE To investigate the efficacy and safety of miglitol in combination with metformin in improving glycemic control in outpatients in whom type 2 diabetes is insufficiently controlled by diet alone. RESEARCH DESIGN AND METHODS In this multicenter, double-blind, placebo-controlled study, 324 patients with type 2 diabetes were randomized, after an 8-week placebo run-in period, to treatment with either placebo, miglitol alone, metformin alone, or miglitol plus metformin for 36 weeks. The miglitol was titrated to 100 mg three times a day and metformin was administered at 500 mg three times a day. The primary efficacy criterion was change in HbA(1c) from baseline to the end of treatment. Secondary parameters included changes in fasting and postprandial plasma glucose and insulin levels, serum triglyceride levels, and responder rate. RESULTS A total of 318 patients were valid for intent-to-treat analysis. A reduction in mean placebo-subtracted HbA(1c) of -1.78% was observed with miglitol plus metformin combination therapy, which was significantly different from treatment with metformin alone (-1.25; P = 0.002). Miglitol plus metformin also resulted in better metabolic control than metformin alone for fasting plasma glucose (-44.8 vs. -20.4 mg/dl; P = 0.0025), 2-h postprandial glucose area under the curve (-59.0 vs. -18.0 mg/dl; P = 0.0001), and responder rate (70.6 vs. 45.52%; P = 0.0014). All therapies were well tolerated. CONCLUSIONS In type 2 diabetic patients, miglitol in combination with metformin gives greater glycemic improvement than metformin monotherapy.