The efficacy of metformin treatment for myocardial infarction: a meta-analysis of randomized controlled trials

Introduction: The efficacy of metformin treatment for myocardial infarction remains controversial. We conduct a systematic review and meta-analysis to explore the impact of metformin versus placebo on myocardial infarction. Methods: We searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases until July 2018 for randomized controlled trials (RCTs) assessing the effect of metformin versus placebo on myocardial infarction. This meta-analysis is performed using the random-effects model. Results: Six RCTs involving 1138 patients are included in this meta-analysis. Overall, compared with the control group of myocardial infarction, metformin treatment had no important impact on major adverse cardiac events (RR = 2.06; 95% CI = 0.90 to 4.74; P = 0.09), reinfarction (RR = 1.60; 95% CI = 0.67 to 3.85; P = 0.29), LVEF (MD = 1.25; 95% CI = -1.51 to 4.01; P = 0.38), NT-proBNP (MD = 0; 95% CI = -0.14 to 0.14; P = 1.0), glucose (MD = 0.05; 95% CI = -0.05 to 0.15; P = 0.31) and HbA1c (MD = 0; 95% CI = -0.02 to 0.02; P = 1.0), but results in the increase in LVEDV (MD = 0.50; 95% CI = 0.43 to 0.57; P < 0.00001) and LVESV were significant (MD = 3.80; 95% CI = 3.75 to 3.86; P < 0.00001). Conclusions: Metformin treatment may not provide significant benefits to patients with myocardial infarction.