Donor sex has no effect on survival in patients receiving red blood cell transfusions

1. In this randomized controlled trial, donor sex did not result in a significant difference in mortality amongst patients receiving red blood cell transfusions.

2. The female-sex donor group was associated with an increased risk of infection in receivers compared to those who received red blood cell transfusions from the male donor group.

Evidence Rating Level: 2 (Good)

Study Rundown: There has been growing evidence of observational data which suggests that the characteristics of red blood cell transfusion donors may impact the outcomes of patients who require transfusions. However, there is a lack of consensus in the current literature as to whether donor characteristics truly impact outcomes and, if so, to what degree and why. This was a double-blind, randomized trial evaluating the effect of donor sex on the survival of patients who require red blood cell transfusions within 8,719 patients in Canada. Results of the study found that there were no significant differences in mortality outcomes of patients receiving red blood cell transfusions by donor sex. Further, there was also no difference in the amount of blood given by male and female donor groups. However, this study had a significant rate of non-adherence, and results are only generalizable to regions with similar transfusion practices and donor pool characteristics. Further extensive studies evaluating the study question in regions with differing practices and donor pools may be beneficial.

Click to read the study in NEJM

In-Depth [randomized controlled trial]: This study was a double-blind, pragmatic, randomized trial evaluating the effect of donor sex on the mortality of recipients receiving red blood cell transfusion. The primary outcome of interest was survival at the end of the trial period. Secondary outcomes included survival at various time points, length of stay, admission to the intensive care unit, number of hospitalizations after transfusion, malignancy, bacterial infections, requiring hemodialysis, myocardial infarction, and the number of red blood cell transfusions required. Participants were included if they received at least one red blood cell transfusion. Participants who did not have a valid health card, received transfusions emergently, and those in whom randomization was not possible were excluded. After applying the inclusion and exclusion criteria, 8,719 patients were randomized in a 60:40 ratio to receive red blood cells from male donor groups and female donor groups. Results of the primary analysis found that there was no significant difference in the number of units of red blood cells received between the male and female donor groups (difference, 0.3 units; 95% Confidence Interval [CI], -0.1 to 0.7), nor was there a difference in overall survival (adjusted hazard ratio, 0.98; 95% CI, 0.91 to 1.06). There was also no difference in secondary outcomes, with the exception of the methicillin-resistant Staphylococcus aureus infection rate, which was higher in the female donor group than male (hazard ratio for infection, 2.00; 95% CI 1.15-3.46). In summary, this study supports the hypothesis that there is no significant survival benefit between male and female donors.

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