Clinical Question: Does metformin (Glucophage) lead to weight loss for obese children and adolescents?
Setting: Outpatient (specialty)
Study Design: Crossover trial (randomized)
Synopsis: Participants were obese patients from nine to 18 years of age (13 boys, 15 girls) who were treated in an endocrine clinic. All had clinical evidence of insulin resistance but did not meet the criteria for diabetes. Patients were randomized (double-blinded) to metformin 1 g twice daily or placebo for six months. This was followed by a six-month crossover period to the other treatment, with a two-week washout period in between.
There were equal numbers of children at Tanner stages 1 and 2 and at Tanner stages 3 to 5 at study entry. Mean body mass index (BMI) was 35 kg per m2. Standardized information on exercise and healthy eating was given to all patients. Four patients dropped out during the study, but not because of medication side effects. At the end of the active treatment period, significant benefits were observed for weight, BMI, abdominal circumference, and fasting insulin levels. The mean treatment effects after six months of active therapy compared with placebo were weight loss of 9.6 lb (4.4 kg), BMI decrease of 1.3 kg per m2, waist circumference decrease of 1.1 inches (2.8 cm), and fasting insulin decrease of 2 mIU per L (14 pmol per L). Data to calculate a number needed to treat were not presented.
Bottom Line: For obese patients nine to 18 years of age, six months of metformin (1 g twice daily) treatment resulted in a mean weight loss of approximately 10 lb (4.5 kg). Larger and longer studies are needed to support the effectiveness and safety of this regimen. (Level of evidence: 1b–)