INTRODUCTION Effectiveness of metformin and lifestyle interventions as an initial treatment in Japanese patients with newly diagnosed type 2 diabetes : a prospective observational study

Optimal control of hyperglycemia and associated risk factors reduces the risk of diabetes-related complications. Metformin is the most widely prescribed biguanide, which lowers blood glucose level primarily through the inhibition of hepatic glucose production. The UK Prospective Diabetes study (UKPDS) showed that metformin reduces the risk of diabetesrelated endpoints, myocardial infarction, diabetesrelated death and all-cause mortality in overweight patients with newly diagnosed type 2 diabetes (1, 2). Moreover, recent observational studies reveal that body mass index (BMI) of patients is unlikely to influence the antihyperglycemic effect of metformi