Efficacy of low-dose metformin in Japanese patients with type 2 diabetes mellitus

The goal of this study was to examine the antihyperglycemic effect of low-dose metformin in nonobese and obese Japanese patients with type 2 diabetes mellitus. After 3 months of reeducation and stabilization of diet therapy (25 kcal/kg of ideal body weight), metformin treatment was initiated. We administered metformin (500 to 750 mg daily) as monotherapy (n = 11) or in combination with a sulfonylurea (n = 14). After 6 months of treatment, the fasting plasma glucose level (mean ± SD) decreased from 190 ± 42 mg/dL to 155 ± 37 mg/dL and the glycated hemoglobin A_1c level (mean ± SD) from 8.8 ± 1.2% to 7.4 ± 1.0% in the monotherapy group. These same variables decreased from 218 ± 60 mg/dL to 162 ± 30 mg/dL and from 9.5 ± 1.2% to 8.4 ± 1.2% in the combination therapy group. All of these changes were statistically significant. Our results demonstrate that even low doses of metformin can improve hyperglycemia in Japanese patients with type 2 diabetes mellitus.