Single-Unit Transfusion Policy in Autologous Hematopoietic Stem Cell Transplantation: Less is Not Worse

•Single-unit transfusion policy reduces RBC utilization by 32% in HSCT.•No significant differences in clinical outcomes between 1-RBC and 2-RBC policies.•1-RBC policy is a straightforward strategy to reduce blood use without compromising care. Single-unit red blood cell (1-RBC) transfusion policy has shown to effectively reduce transfusion burden while maintaining comparable clinical outcomes in hematological patients compared to the classical double-unit policy. However, its effects specifically after autologous stem cell transplantation (ASCT) have not been previously studied. We aimed to evaluate the impact of the 1-RBC policy on transfusion burden in a homogeneous cohort of patients undergoing ASCT. We retrospectively compared the transfusion requirements and the clinical outcomes of 187 patients transplanted from May 2019 to December 2022 under a 1-RBC policy, with a historical cohort of 153 patients transplanted from January 2016 to April 2019 under a double-unit policy. The 1-RBC policy was associated with a 32% reduction in RBC utilization and lower number of RBC transfusions at day 30 after transplantation (median 2 versus 3 units; P < .0001), with an odds ratio of 0.49 in multivariate analysis (P = .03). However, the number of transfusion episodes remained similar (median of 2 in both arms; P = .34). No significant differences in length of stay, hemoglobin levels at discharge or 30‐day mortality were observed. In conclusion, transitioning to the 1-RBC represents a straightforward action in current practice that significantly reduces blood transfusions in patients undergoing ASCT, without negatively impacting clinical outcomes. [Display omitted]