Life Is a Highway or a Long and Winding Road: A Look into Why Some Transplants Lead to Longer Length of Stay (LOS)

BACKGROUND There is an increased need for allogeneic hematopoietic stem-cell transplantation (allo-HCT) globally and this causes more pressure on transplant units. This study aims to identify predictors of prolonged LOS for patients (pts) who underwent allo-HCT at Princess Margret Cancer Centre (PMCC). METHODS We conducted a retrospective study that included 977 pts who underwent allo-HCT at the PMCC between 2017 and 2022. We looked at pre and post-transplant factors that impact the LOS after allo-HCT. RESULTS The median follow-up was 25.9 months (range: 0.7- 69.6). The median age was 58 years (18-76), 36.4% had hematopoietic cell transplant- comorbidity index(HCT-CI) ≥3, 18.4% had Karnofsky performance status (KPS) <90%. Haploidentical donors were 19.7%, 23.5% were matched related, 9.3% were mismatched unrelated donors (MMUD).The median LOS for the pts who underwent allo-HCT in the period between 2020-2022 was 35 days (d) vs 40.5 d for pts between 2017-2019, P<0.001.We looked at pre-transplant factors that affected the LOS, we found that HLA-mismatched donors (Hazard ratio HR=1.16, 95% CI: 1.09-1.23), P<0.001, KPS <90 (HR=1.12, 95% CI: 1.05-1.19), P=0.001, transplanted between 2017-2019 (HR=1.17, 95% CI: 1.08-1.22), P<0.001, and bone marrow as a source of stem cells (HR=1.11, 95% CI: 1.04-1.18), P=0.001, were the only pre-transplant factors that impacted LOS. The shorter LOS between 2020-2022 can be explained by interventions implemented during this period [Salas, et al. 2022].When we looked at patients transplanted between 2020 and 2022, we identified the following factors: KPS <90 (HR=2.72, 95% CI: 1.57-4.69), P<0.001, HLA-mismatched donors (HR=1.83, 95% CI: 1.11-3.02), P=0.02, and age > 65 yr (HR=1.78, 95% CI: 1.05-3.02), P=0.03. LOS for patients with 0-1 RF was 34 d vs 41 d for patients with 2-3 RF, p<0.001, Fig.1. The 1-year overall survival (OS) for pts with 0-1 RF was 81.0% [95% CI: 76.2-84.9)] vs 56.0% [95% CI: 43.3-67.0)], p<0.001 for 2-3 RF, Fig.2.Then we identified acute graft-versus-host disease grade III-IV (aGVHD III-IV) (HR=1.36, 95% CI: 1.28-1.44), P<0.001, veno-occlusive disease of the liver (VOD) (HR=1.06, 95% CI: 1.00-1.12), P=0.04, graft failure (GF) (HR=1.15, 95% CI: 1.08-1.21), P<0.001, hemorrhagic cystitis (HC) (HR=1.17, 95% CI: 1.10-1.23), P<0.001, bloodstream infections (BSI) (HR=1.17, 95% CI: 1.11-1.24), P<0.001, cytomegalovirus (CMV) reactivation (HR=1.09, 95% CI: 1.03-1.15), P=0.003, Epstein-Barr virus (EBV) reactivation (HR=1.07, 95% CI: 1.01-1.13), P=0.03, and post-transplant lymphoproliferative disease (PTLD) (HR=1.07, 95% CI: 1.01-1.13), P=0.02 as factors of significance impact. CONCLUSION In spite of interventions that shortened LOS between 2020-2022, age > 65, mismatched donors, and KPS<90 are associated with prolonged LOS and worse OS. Personalized medicine may be of value in preventing and treating post-allo-HCT complications.