Less is More When it Comes to Blood Transfusions
Question
Does a restrictive transfusion strategy with a hemoglobin trigger of less than 7g/dL improve outcomes as compared with a more liberal strategy?
Bottom line
A restrictive strategy using a hemoglobin transfusion trigger of less than 7g/dL leads to decreased morbidity and mortality. Based on this data, you would need to treat 33 patients with a restrictive strategy to prevent 1 death. Additionally, this strategy resulted in a 40% reduction in the number of patients who received a blood transfusion.
Reference
Salpeter SR, Buckley JS, Chatterjee S. Impact of more restrictive blood transfusion strategies on clinical outcomes. Am J Med 2014;127(2):124-131. (LOE: 1a-)
Allocation
(Uncertain)
Design
Meta-analysis (randomized controlled trials)
Setting
Various (meta-analysis)
Synopsis
These investigators searched MEDLINE for randomized controlled trials that compared a restrictive blood transfusion strategy using a transfusion trigger of hemoglobin of less than 7g/dL with a more liberal strategy. The authors did not state how study selection was performed, but 2 investigators independently extracted data from included studies. No formal quality assessment was performed. Three studies, with a total of 2364 patients, were chosen for the primary analysis. One study evaluated transfusion strategies in adult critical care, one in pediatric critical care, and one in patients with acute upper gastrointestinal bleeding. When pooled together, the data showed that a restrictive transfusion strategy led to decreased in-hospital mortality (relative risk (RR) = 0.74; 95% CI, 0.60-0.92), as well as decreased overall mortality (RR = 0.80; 0.65-0.98). Other benefits to a restrictive strategy included reduced incidences of acute coronary syndrome, pulmonary edema, and rebleeding. A secondary meta-analysis looked at 16 trials that used a less restrictive transfusion strategy with a hemoglobin trigger range from 7.5 g/dL to 10 g/dL. As compared with a more liberal strategy, this did not significantly affect morbidity or mortality. Although there was no evidence of heterogeneity in the results, it is noted that the 3 trials included in the primary analysis had very different patient populations with different indications for transfusion.
Dr. Kulkarni is an assistant professor of hospital medicine at Northwestern University in Chicago.
