Metformin monotherapy in children and adolescents with type 2 diabetes mellitus in Japan

Objective To evaluate the safety and effectiveness of metformin monotherapy for 52 weeks, including 24 weeks of treatment and a 28-week extension period for evaluation of long-term safety, in 37 Japanese pediatric patients with type 2 diabetes mellitus. Research design and methods This study design was an open-label, non-randomized, multicenter trial. The primary effectiveness endpoint was the changes from baseline to the final visit at 24 weeks in HbA1c. The secondary endpoints were the rate for achieving the treatment goal, and the changes in glycated albumin, fasting blood glucose, fasting insulin, HOMA-IR, and fasting serum lipids. Metformin was administrated at the dose of 500 mg/day up to a maximum of 2000 mg/day taken in two or three divided doses. Results The mean change of HbA1c at the final visit at 24 weeks for 20 metformin-naïve patients (Group A) was − 0.66 ± 0.95% and that of 17 already-on metformin patients (Group B) was − 0.98 ± 1.62%. These figures proved the effectiveness of metformin as defined before the study. Secondary effectiveness endpoints were also improved. The improvement of blood glucose, fasting insulin and serum lipid levels proved the effectiveness of metformin without increasing body weight. Adverse effects such as nausea and diarrhea were observed in 35 of the 37 subjects and drug-related adverse events were observed in 19 patients. However, these events were not serious and did not increase with long-term treatment. Conclusions Metformin is safe and effective for Japanese pediatric patients with T2DM.