Red blood cell transfusion burden by day 30 predicts mortality in adults after single-unit cord blood transplantation

Increased red blood cell (RBC) transfusion requirements are associated with morbidity and mortality after allogeneic hematopoietic cell transplantation. However, its impact on the outcomes after cord blood transplantation (CBT) is unclear. We retrospectively analyzed the data of 278 adult patients who received single-unit CBT in our institute. The median number of RBC transfusions for each patient was 12 units (range, 4-66) by day 30 and 14 units (range, 4-70) by RBC engraftment. Sex, cord blood CD34⁺ cell dose, cytomegalovirus serostatus, total body irradiation dose in the conditioning regimen, ABO blood group incompatibility, and pre-CBT RBC transfusion requirements were significantly associated with the number of RBC transfusion units in the linear regression analysis. In the multivariate analysis, RBC transfusion ≥18 units by day 30 was significantly associated with higher overall mortality (hazard ratio, 1.86; P = 0.018). These data suggested that early RBC transfusion burden was significantly associated with overall mortality in adult patients undergoing single CBT. Early RBC transfusion burden might be a surrogate marker for poor outcomes after single CBT.