Blood donor–recipient sex mismatch: outcomes impacted?

Abstract

Background and objectivesA number of recent publications have questioned whether female donor transfusions (particularly of red cells) or donor–recipient sex mismatch are associated with increased risk for mortality. A systematic review was conducted to further explore this concern.Materials and methodsA literature search was performed to identify original studies linking red‐blood‐cell transfusion donor or recipient gender to mortality risk. Exclusion criteria included (1) absence of a focus on gender mismatch and mortality outcomes, (2) nonclinical studies, (3) non‐English language studies.ResultsThe initial search strategy yielded 136 results and 8 studies met all selection criteria. An additional 2 studies were found by supplemental search. Six of the ten studies reported increased mortality risk with sex mismatch, while four reported no increase in mortality. Study end‐points varied, thus limiting generalizability. Conflicting evidence was noted in regard to female donor sex, sex mismatch, directionality of risk, age of donors and recipients, and transfusion burden.ConclusionAdditional studies are needed to resolve this issue. As the majority of studies relied upon a ‘big data’ approach, there is concern for subtle confounding.