Effects of metformin on endothelial function in type 2 diabetes.

The aim of the present study was to examine the effect of metformin on endothelial function in patients with type 2 diabetes mellitus (T2DM). In total, 93 patients with T2DM and dissatisfactory glycemic control were randomly assigned to the metformin and pioglitazone groups and changes in vascular endothelial function were subsequently observed. Blood sugar levels and the insulin resistance (IR) index of the patients prior to treatment were lower than those following 12 months of treatment. In addition, fasting and postprandial insulin levels and the insulin function index were higher compared with those obtained following 12 months of treatment (P<0.05). Following 12 months of treatment, the body mass index (BMI) in the metformin group was lower than that in the pioglitazone group (P<0.05). Vascular endothelial function had improved in the groups following 12 months of treatment, when compared with the levels prior to treatment (P<0.05). Following 12 months of treatment, endothelial function in the metformin group had improved markedly compared with that in the pioglitazone group (P<0.05). Therefore, the administration of metformin and pioglitazone in patients with T2DM may improve insulin function, reduce the role of IR and improve endothelial function. Metformin is more successful than pioglitazone in reducing BMI and improving endothelial function.