Metformin as adjunctive therapy for adolescents with type 1 diabetes and insulin resistance lowered hemoglobin A1c levels and decreased insulin dosage with no weight gain.
“This improvement may have been attributable to the direct impact of metformin on peripheral tissues, but more likely was secondary to metformin’s effects on decreased hepatic glucose output, or, possibly, as a consequence of weight loss subsequent to a decreased appetite,” they said
In this small randomized, placebo-controlled study, 27 children aged 12-17 years who attended the diabetes clinic at the hospital were recruited. Patients had suboptimal metabolic control, which was defined as a hemoglobin A1c (HbA1c) level greater than 8% but less than 11% for the prior 6 months, and insulin dosage of 1 U/kg per day or greater. Of the 27 patients, 14 received metformin and 13 received placebo, and all were monitored over a 3-month period.
The metformin dose was started at 500 mg/day at breakfast and was increased by 500 mg/day each week to a maximum of 1,000 mg/day for children who weighed less than 50 kg, 1,500 mg/day for children who weighed 50-75 kg, and 2,000 mg/day for those who weighed more than 75 kg.
At the end of the study, children who took metformin had significantly lower HbA1c levels (0.6% lower) and daily insulin dosages (an average of 0.12 U/kg per day lower), compared with those on placebo. There was no significant change in body mass index between the two groups. Diabetes Care 26:138-43, 2003.