Blood transfusion and mortality in myocardial infarction: an updated meta-analysis

Background: Several observational and preclinical studies have shown that blood transfusion may modify the mortality of patients with myocardial infarction (MI). The aim of this meta-analysis is to evaluate the recent evidence on the effectiveness of blood transfusion for all-cause mortality in patients with MI. Materials and Methods: PUBMED, EMBASE and the Cochrane central register of controlled trials were searched up to June 2016 by two independent investigators. Studies were considered eligible if they recruited adult MI patients and reported hazard ratio (HR) for all-cause mortality comparing those who received blood transfusion with those who did not receive blood transfusion. We abstracted and calculated pooled HRs using a random-effects model. Results: From 4277 unique reports, we identified 17 studies including 260811 patients with 11 studies examining short-term (in hospital/30-day) all-cause mortality and 9 studies examining long-term (more than 30 days) all-cause mortality. Meta-analysis demonstrated that patients treated with blood transfusion had increased short-term all-cause mortality (HR, 2.39, 95% CI 1.81 to 3.15) compared with those without blood transfusion treatment. Similar findings were observed by subgroup analyses. We also find significant association between blood transfusion and long-term all-cause mortality (HR 1.90, 95% CI 1.40 to 2.58) for MI patients. Conclusions: In patients with MI, blood transfusion treatment is associated with patient short-term and long-term all-cause mortality. However, further large-scale prospective studies are needed to establish its validity of this association.