[The causes of death in elderly patients undergoing haploidentical stem cell transplantation]

Objective: To analyze the causes of death in elderly patients after haploidentical stem cell transplantation (haplo-HSCT) . Method: This single-center retrospective cohort study included 404 patients aged >55 years who underwent haplo-HSCT at Peking University People's Hospital between January 3, 2019, and December 14, 2023, and analyzed the causes of death among those who died. Results: The last follow-up was October 11, 2025, with a median follow-up duration of 708 (12-2 343) days. A total of 139 patients died after transplantation, with a mortality rate of 34.4%. Relapse was the leading cause of death (40.3%), followed by infection (33.8%) and graft-versus-host-disease (11.5%). Subgroup analysis revealed that relapse was the primary cause of death in patients with myeloid malignancies, whereas infection was most common in those with lymphoid malignancies. Patients in non-remission and those with minimal residual disease-positive status exhibited higher relapse death rates, representing the predominant cause of death. Factors such as patient age, HCT-CI, donor-specific antibody status, conditioning regimens, stem cell source, and post-transplantation phases did not significantly influence the causes of death. Conclusion: Relapse and infection remain the primary causes of death in older patients following haplo-HSCT.