RBC and Platelet Transfusion Requirements in the First 30 Days after Allogeneic Hemopoietic Cell Transplantation and Transfusion Independence: A Single Center Retrospective Study of 1803 Recipients

Background Allogeneic hematopoietic cell transplant (allo-HCT) recipients often require substantial but variable transfusion support. Few studies have quantified their transfusion burden, or identified prognostic factors for increased transfusions to guide patient counseling or inventory management. Data on haploidentical HCT (Haplo-HCT) patients are especially scarce. Objectives To identify factors associated with increased RBC and platelet (PLT) transfusions, and provide for the first time data on a large cohort of Haplo-HCT patients. Methods We retrospectively evaluated 1803 consecutive first time adult allo-HCT patients transplanted at our center in 2011-17. Multivariate linear regression and Fine-Gray subdistribution hazards models were used to examine the associations between baseline characteristics (age, sex, disease stage, graft type, donor type, ABO compatibility and conditioning regimen) and log-transformed transfusion units in the first 30 days after HCT and time to reach transfusion independence respectively. Results The median age of the cohort was 53(18-78); 56.2% were male. Most common diagnoses were AML (38.8%), ALL (19.6%), and lymphoma (14.8%); 50.2% had advanced disease. Patients received nonmyeloablative/reduced intensity (58.9%) or myeloablative conditioning regimens (MAC, 41.1%), followed by peripheral blood stem cell (88.4%), bone marrow (6.9%) or umbilical (UC, 4.7%) HCT. Most grafts were from matched related (MRD, 38.7%) or unrelated (MUD, 49.1%) donors, and 7.6% were haploidentical. ABO incompatibility (Major 15.8%, minor 18.6%, bi-directional 8.5%) was present in 42.9% of the cases (Table 1). Most of the 1764 patients who survived 30+ days received RBC (88.2%) or PLT (97.2%) transfusions during the first 30 days, with a median of 3 (0-37) RBC and 5(0-144) apheresis PLT units. RBC and PLT transfusion independence was reached in 28 (95%CI: 26-31) and 12 (95%CI: 12-13) days respectively. Multivariate analyses showed that Haplo-HCT and UC graft were independently associated with more RBC and PLT transfusions, as were advanced disease, ABO incompatibility, older age, and MAC (P Conclusions We identified patient and transplant factors strongly associated with increased transfusions in the first 30 days after allo-HCT, and quantified the transfusion burden of Haplo-HCT relative to other types of HCT.