(HealthDay News) – For obese children without diabetes, metformin is associated with a modest, but statistically significant, reduction in body mass index (BMI), according to a review published online Dec. 16 in JAMA Pediatrics.

Marian S. McDonagh, PharmD, from the Oregon Health & Science University in Portland, and colleagues conducted a systematic literature review to examine the effectiveness and safety of metformin for treating obesity in children (aged ≤18 years) without a diagnosis of diabetes mellitus. Fourteen randomized studies were identified and included in analyses.

The researchers found that at six months there was moderate-strength evidence that metformin was associated with a 1.38 (95% confidence interval [CI], −1.93 to −0.82) reduction in BMI from baseline, compared with control. In studies of <6 months the effect was similar, but lessened; while in studies of one year of treatment, the pooled estimate was not significant. Smaller, but significant effects were seen in subgroup analyses for those with baseline BMI <35kg/m²; those of Hispanic ethnicity; those with acanthosis nigricans; those who had failed diet and exercise programs; and in studies with more girls or higher mean age. No serious adverse events were reported, although moderate-strength evidence indicated more gastrointestinal events with metformin (26%) vs. control groups (13%; relative risk, 2.05; 95% CI, 1.19–3.54).

“Metformin provides a statistically significant, but very modest reduction in BMI when combined with lifestyle interventions over the short term. A large trial is needed to determine the benefits to subgroups or impacts of confounders,” the authors conclude. “In the context of other options for treating childhood obesity, metformin has not been shown to be clinically superior.”

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