Combined glibenclamide plus metformin improves insulin sensitivity in non-obese Type 2 diabetic patients

The aim of this study was to evaluate the efficacy of a treatment with metf ormin (alone or combined with a sulphonylurea) on glycaemic control and ins ulin sensitivity in non-obese patients with Type 2 diabetes mellitus alread y treated with sulphonylureas alone. Fifteen non-obese (BMI < 30 kg/m(2)) p atients already satisfactorily treated (HbA(1c) <7.5 %) with sulphonylureas were studied, Patients were first switched to glibenclamide alone for at l east one month, then blindly divided into 3 groups: metformin, glibenclamid e, and metformin + glibenclamide. Insulin sensitivity was evaluated before, and after one month, with the steady state plasma glucose concentration re ached after a constant infusion of glucose, insulin and octreotide (SSPG), Fasting and post-breakfast glucose, insulin and C-peptide were also assayed , Patients' clinical data were similar in the three groups (BMI: 27.1+/-0.6 kg/m(2); HbA(1c): 7.2+/-0.5 %; fasting glycaemia: 8.8+/-0.8 mmol/l; post-p randial glycaemia: 10.9+/-1.1 mmol/l), SSPG, similar before the study (9.31 +/-0.12 mmol/l), significantly improved in patients treated with combined t herapy (7.56+/-0.42), worsened in patients switched to metformin (11.9+/-0. 56), BMI remained unchanged in the three groups; fasting glycaemia decrease d slightly in patients treated with combined therapy and increased in patie nts treated with metformin. These results demonstrate that metformin, combi ned with glibenclamide, improves peripheral insulin sensitivity. Taking int o account the pivotal role of insulin resistance in Type 2 diabetes mellitu s, a therapeutic protocol of association (sulphonylurea + metformin) could be suggested as first choice even in non-obese diabetic patients.