Improved glycaemic control by addition of glimepiride to metformin monotherapy in Type 2 diabetic patients

AIM: To compare the effect of glimepiride in combination with metformin with monotherapy of each drug on glycaemic control in Type 2 diabetic patients. DESIGN AND METHODS: Randomized, double-blind, double-dummy, parallel-group multicentre study conducted in France. Type 2 diabetic patients aged 35-70 years inadequately controlled by metformin monotherapy 2550 mg daily for at least 4 weeks were randomized to either metformin, glimepiride or metformin and glimepiride. RESULTS: Three hundred and seventy-two patients aged 56 +/- 8 years were treated for 5 months. Combination treatment was significantly more efficient in controlling HbA1c (% change + 0.07 +/- 1.20 for metformin, + 0.27 +/- 1.10 for glimepiride, -0.74 +/- 0.96 for combination treatment, P < 0.001), fasting blood glucose (FBG) (mmol/l change + 0.8 +/- 0.4 for metformin, + 0.7 +/- 3.1 for glimepiride and -1.8 +/- 2.2 for combination treatment, P < 0.001) and post-prandial blood glucose (PPBG) (mmol/l change + 1.1 +/- 5.9 for metformin, + 0.1 +/- 5.1 for glimepiride and -2.6 +/- 3.9 for combination treatment, P < 0.001) than either glimepiride or metformin alone. There was no significant difference between metformin or glimepiride monotherapy with respect to the change in HbA1c or FBG; however, glimepiride was significantly more effective than metformin in reducing PPBG. The incidence of symptomatic hypoglycaemia was higher in the combination group than in either monotherapy group (P = 0.039). CONCLUSIONS: Addition of glimepiride to metformin in Type 2 diabetic patients inadequately controlled by metformin alone resulted in superior glycaemic control compared with glimepiride or metformin monotherapy.