Abstract 9102: Blood Transfusion is Associated with Increased Mortality in Myocardial Infarction-A Meta-analysis and Diversity-Adjusted Study Sequential Analysis

Abstract

Introduction: The benefit of blood transfusion in patients with myocardial infarction is controversial and harm may be imminent.

Hypothesis: To identify risk of mortality with blood transfusion in patients with myocardial infarction, through a meta-analysis of published data.

Methods: A systematic search of studies published between 1966 and March, 2012 was conducted using MEDLINE, EMBASE, CINAHL, Scopus, the Web of Science and Cochrane CENTRAL databases. English-language studies comparing blood transfusion with no transfusion; or a liberal versus restricted transfusion strategy was identified. Two study authors independently reviewed the 729 titles and abstracts originally identified and selected 10 for analysis. Quality of each study was assessed using the strengthening Meta-analysis of Observational Studies in Epidemiology (MOOSE) checklist. Studies of transfusion strategies in anemia associated with myocardial infarction, and all-cause mortality rates at the longest available follow-up for the individual study, were abstracted. Pooled-effect estimates were calculated with random-effects models.

Results: Analyses of transfusion in myocardial infarction revealed increased all-cause mortality with a strategy of transfusion during myocardial infarction-18.2% Vs 10.2% [RR 2.91 ( 95% CI 2.46-3.44); p<0.001], with weighted absolute risk increase of 12 %, and a number needed to harm of 8 (95% CI 6-17). However, the mortality risk with transfusion was mitigated when restricted to STEMI patients and those having hematocrit below 30. Multivariate meta-regression revealed that transfusion was associated with higher risk of mortality, independent of baseline hemoglobin, nadir hemoglobin and change in hemoglobin. A higher risk with transfusion compared with no/restrictive transfusion was noted for subsequent myocardial infarction rates too.

Conclusion: A strategy of blood transfusion/ liberal blood transfusion compared to no/restricted blood transfusion was associated with a higher incidence of all-cause mortality. A practice of routine/liberal blood transfusion in myocardial infarction should not be encouraged but investigated in a large trial with low risk of bias.