The Effect of Metformin on Antipsychotic-induced Weight Gain in Patients with Schizophrenia or Schizoaffective Disorder: A Systematic Review and Meta-analysis of Randomized Placebo-Controlled Trials

ABSTRACT

BACKGROUND: In this systematic review and meta-analysis, the effect of metformin on weight loss was assessed to determine whether metformin should be recommended for the prevention or treatment of weight gain in patients receiving antipsychotic medication for the treatment of schizophrenia or schizoaffective disorder. METHODS: The PubMed, Embase, and Cochrane Library databases were searched for all published randomized controlled trials (RCTs) from inception to June 2018. In addition, the references of relevant articles were also examined. Using Review Manager 5, the pooled estimates of the weighted mean difference (WMD) of the changes in body weight and body mass index (BMI) and the corresponding 95 % confidence intervals (CIs) were calculated. RESULTS: The meta-analysis included 15 RCTs. The pooled analysis showed that compared with placebo, metformin led to significant reductions in body weight (WMD: −2.09, 95% CI: −2.59, −1.60; p<0.00001) and BMI (WMD: −0.90, 95% CI: −1.08, −0.72; p<0.00001). The effect of metformin on weight loss was greater in patients receiving olanzapine than in patients receiving clozapine (body weight, WMD: −2.39, 95% CI: −3.76, −1.02; p=0.0006 for olanzapine; −1.99, 95% C: −3.47, −0.51; p=0.009 for clozapine; BMI, WMD: −1.15, 95% CI: −1.74, −0.57, p=0.0001 for olanzapine; WMD: 0.76, 95% CI: −1.23, −0.28; p=0.002 for clozapine). CONCLUSION: Metformin can be recommended to manage olanzapine-induced weight gain in patients with schizophrenia or schizoaffective disorder. The magnitude of the reductionss in body weight and BMI implieds that the use of metformin to attenuate olanzapine-induced weight gain can minimize the risk of coronary heart disease.