Metformin Therapy Reduces Obesity Indices in Children and Adolescents: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.

Purpose: Few studies have summarized findings for the effect of metformin on obesity indices. Therefore, we aimed to conduct a systematic review and meta-analysis on the effect of metformin on obesity indices among children and adolescents. Methods: Relevant articles published up to September 2018 were searched in SCOPUS, Medline, and Google Scholar using appropriate keywords. All clinical trials that examined the effect of metformin on obesity indices in children and adolescents were included. Results: Overall, 38 studies, including 2199 participants (39.75% male and 60.25% female), were included. The pooled results indicated that metformin significantly reduced BMI [weighted mean difference (WMD): -1.07 kg/m2; 95% confidence interval (CI): -1.43 to -0.72]. Same findings were found for waist circumference (WC) (WMD: -1.93 cm; 95% CI: -2.69 to -1.16). Metformin also reduced body weight in all participants (WMD: -2.51 kg; 95% CI: -3.14 to -1.89). Moreover, it reduced body fat mass in patients with overweight or obesity (WMD: -1.90%; 95% CI: -3.25 to -0.56) and chronic diseases (WMD: -1.41%; 95% CI: -2.23 to -0.58), but not among those with growth problems. Metformin therapy did not affect lean body mass (LBM) in patients with overweight or obesity and growth problems; however, it reduced LBM in patients with chronic diseases (WMD: -1.49 kg; 95% CI: -2.69 to -0.30). Conclusions: We found a significant reduction in BMI, body weight, WC, and fat mass following administration with metformin. However, the effect of metformin on LBM was not significant. Further studies are required to confirm these findings.