[Impact of recipient age on outcomes of allogeneic hematopoietic stem cell transplantation: an analysis from the Chinese Bone Marrow Transplant Registry Group (CBMTRG)].

Abstract

Objective: To investigate whether recipient age independently affects outcomes after allogeneic hematopoietic stem cell transplantation (allo-HSCT), including the predominant patterns of treatment failure, after adjustment for confounding factors. Methods: This retrospective, multicenter cohort study included 1 619 patients who underwent a single allo-HSCT at five transplant centers from January 1 2018, to December 31 2023. Patients were categorized into younger (≤35 years) or older recipient groups (≥50 years). After propensity score matching to balance 11 covariates, the analysis included 694 patients (347 in each group). Overall survival (OS), non-relapse mortality (NRM), cumulative incidence of relapse (CIR), and cumulative incidence of acute and chronic graft-versus-host disease (aGVHD and cGVHD) were compared between the groups. Results: The median follow-up was 33.4 months (95% CI: 31.2 - 36.1 months). The 3-year OS rate was significantly lower in older than in younger recipients (75.5% ± 2.5% vs 83.1% ± 2.2%, HR=1.59, P=0.007). The 3-year NRM was higher in older recipients [13.3% ± 1.9% vs 8.5% ± 1.6%, univariable subdistribution HR (SHR) =1.61, P=0.044]. This association did not reach conventional statistical significance after multivariable adjustment (adjusted SHR=1.59, 95% CI: 0.99 - 2.54, P=0.053) ; however, the stable effect estimate indicated clinical relevance. No statistically significant between-group differences were observed in CIR or in the cumulative incidences of grade Ⅱ-Ⅳ aGVHD and cGVHD. Infection was the leading cause of NRM in both groups, whereas the proportions of deaths attributable to organ dysfunction and bleeding were higher among older recipients. Conclusion: After propensity score matching, older recipient age remained independently associated with poorer OS. This unfavorable outcome was primarily characterized by an increased risk of NRM, rather than that of relapse.