Association of Blood Transfusion With Increased Mortality in Myocardial Infarction: A Meta-analysis and Diversity-Adjusted Study Sequential Analysis

Study Questions:

What is the impact of blood transfusion on outcome of patients with myocardial infarction?

Methods:

The authors performed a meta-analysis of 10 studies comparing blood transfusion with no blood transfusion or a liberal versus restricted blood transfusion strategy. Pooled-effect estimates were calculated with random-effects models.

Results:

In the pooled analysis, there was an increase in all-cause mortality associated with a strategy of blood transfusion versus no blood transfusion in patients with myocardial infarction (18.2% vs. 10.2%; risk ratio, 2.91; 95% confidence interval [CI], 2.46-3.44; p < 0.001), with a number needed to harm of eight (95% CI, 6-17). In multivariate meta-regression, blood transfusion was associated with a higher risk for mortality independent of baseline hemoglobin level, nadir hemoglobin level, and change in hemoglobin level during the hospital stay. Blood transfusion was also significantly associated with a higher risk for subsequent myocardial infarction (risk ratio, 2.04; 95% CI, 1.06-3.93; p = 0.03).

Conclusions:

Blood transfusion is associated with a higher all-cause mortality in patients with myocardial infarction.

Perspective:

The poor outcome of patients with myocardial infarction who bleed or need transfusion has been demonstrated in multiple studies. This meta-analysis pools the results of these studies and provides more reliable estimates. It is, however, unclear if there is a causal relation and if transfusing eight patients actually results in one extra death. There are many good reasons to avoid unnecessary transfusion, and even in the absence of strong randomized data, it would be prudent to avoid transfusion unless absolutely necessary in patients with myocardial infarction.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Blood Transfusion, Risk, Myocardial Infarction, Hemoglobins, Erythrocyte Transfusion, Death, Cardiovascular Diseases, Confidence Intervals, Angioplasty, Balloon, Coronary, Length of Stay


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