Objective: To evaluate the efficacy of metformin versus a placebo in the treatment of patients with simple obesity without obesity related diseases.
Methods: A search was done on Pub-Med, EMBASE, Cochrane, and Science Citation Index Expanded databases. The main inclusion criteria included the following:(1) randomized controlled trials. (2) patients diagnosed as being overweight or obese. (3) patients were randomly assigned to receive metformin or control. Exclusion criteria included the following: patients diagnosed with an obesity related disease, such as diabetes mellitus (DM) or polycystic ovary syndrome (PCOS).
Results: Compared with the placebo, weighted mean difference (WMD) was 2.33 (95% CI 0.31, 4.35) kg higher with metformin (p = 0.02). Compared with the placebo, WMD was 0.57 (95% CI 0.35, 0.79) kg/m² higher with metformin(p < 0.00001). There was no significant difference in the reduction of waist circumference between the metformin group and the control group (p = 0.05). The fasting blood glucose levels were significantly lower in the metformin group than in the control group (p < 0.00001). However, no hypoglycemia was noted in the metformin group or the control group.
Conclusion: Metformin is effective in reducing body weight of simple obesity patients, and metformin does not induce hypoglycemia as a side effect.
Keywords: Meta-analysis; Metformin; Obesity; Overweight; Weight loss.