Antipsychotic-induced
dyslipidemia could increase the risk of
cardiovascular diseases. This is a meta-analysis of randomized double-blind placebo-controlled trials to examine the efficacy and safety of adjunctive
metformin for
dyslipidemia induced by
antipsychotics in
schizophrenia. The standardized mean differences (SMDs) and risk ratios (RRs) with their 95% confidence intervals (CIs) were calculated using the random-effects model with the RevMan 5.3 version software. The primary outcome was the change of serum
lipid level. Twelve studies with 1215
schizophrenia patients (592 in
metformin group and 623 in placebo group) were included and analyzed. Adjunctive
metformin was significantly superior to placebo with regards to
low density lipoprotein cholesterol (
LDL-C) [SMD: -0.37 (95%CI:-0.69, -0.05), P = 0.02; I2 = 78%], total
cholesterol [SMD: -0.47 (95%CI:-0.66, -0.29), P < 0.00001; I2 = 49%],
triglyceride [SMD: -0.33 (95%CI:-0.45, -0.20), P < 0.00001; I2 = 0%], and
high density lipoprotein cholesterol [SMD: 0.29 (95%CI:0.02, 0.57), P = 0.03; I2 = 69%]. The superiority of
metformin in improving
LDL-C level disappeared in a sensitivity analysis and 80% (8/10) of subgroup analyses.
Metformin was significantly superior to placebo with regards to decrease in
body weight, body mass index,
glycated hemoglobin A1c, fasting
insulin, and homeostasis model assessment-
insulin resistance (P = 0.002-0.01), but not regarding changes in waist circumference, waist-to-hip rate,
leptin, fasting
glucose, and blood pressure (P = 0.07-0.33). The rates of discontinuation due to any reason [RR: 0.97 (95%CI: 0.66, 1.43), P = 0.89; I2 = 0%] was similar between the two groups. Adjunctive
metformin could be useful to improve total
cholesterol and
triglyceride levels, but it was not effective in improving
LDL-C level in
schizophrenia.