title: Metformin for olanzapine-induced weight gain: a systematic review and meta-analysis.
abstract: Olanzapine is an atypical antipsychotic that is useful in schizophrenia and bipolar affective disorder, but its use is associated with troublesome weight gain and metabolic syndrome. A variety of pharmacological agents has been studied in the efforts to reverse weight gain induced by olanzapine, but current evidence is insufficient to support any particular pharmacological approach. We conducted a systematic review and meta-analysis of randomized controlled trials of metformin for the treatment of olanzapine-induced weight gain. Systematic review of the literature revealed 12 studies that had assessed metformin for antipsychotic-induced weight gain. Of these, four studies (n= 105) met the review inclusion criteria and were included in the final analysis. Meta-analysis was performed to see the effect size of the treatment on body weight, waist circumference and body-mass index (BMI). Weighted mean difference (WMD) for body weight was 5.02 (95% CI 3.93, 6.10) kg lower with metformin as compared with placebo at 12 weeks. For waist circumference, the test for heterogeneity was significant (P= 0.00002, I(2) = 85.1%). Therefore, a random effects model was used to calculate WMD, which was 1.42 (95% CI 0.29, 3.13) cm lower with metformin as compared with placebo at 12 weeks. For BMI, WMD was 1.82 (95% CI 1.44, 2.19) kg m(-2) lower with metformin as compared with placebo at 12 weeks. Existing data suggest that short term modest weight loss is possible with metformin in patients with olanzapine-induced weight gain.
authors.affiliation: Central Institute of Psychiatry, Kanke, Ranchi 834006, India Department of Psychiatry, KPC Medical College and Hospital, Jadavpur, Kolkata 700032, India. samirpsyche@yahoo.co.in
authors.forename: Samir Kumar
authors.initials: SK
authors.lastname: Praharaj
authors.forename: Amlan Kusum
authors.initials: AK
authors.lastname: Jana
authors.forename: Nishant
authors.initials: N
authors.lastname: Goyal
authors.forename: Vinod Kumar
authors.initials: VK
authors.lastname: Sinha
mesh_terms: D014150:Antipsychotic Agents / Q000009:adverse effects*; D001569:Benzodiazepines / Q000009:adverse effects; D001714:Bipolar Disorder / Q000188:drug therapy*; D001786:Blood Glucose; D015992:Body Mass Index; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D008687:Metformin / Q000627:therapeutic use; D000077152:Olanzapine; D050177:Overweight / Q000139:chemically induced*; D016032:Randomized Controlled Trials as Topic; D012559:Schizophrenia / Q000188:drug therapy*; D015430:Weight Gain / Q000187:drug effects*
chemical_list: D014150:Antipsychotic Agents; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D001569:Benzodiazepines; D008687:Metformin; D000077152:Olanzapine