Adoption and inpatient outcomes of chimeric antigen receptor T-cell therapy in lymphomas and leukemias: A national analysis, 2017–2023.

e19104 Background: Chimeric antigen receptor T-cell (CAR-T) therapy has transformed the management of relapsed or refractory hematologic malignancies. Despite increasing outpatient administration, CAR-T therapy remains frequently delivered in the inpatient setting, with substantial resource utilization. Contemporary national data describing real-world inpatient adoption patterns and outcomes across malignancy subtypes are limited. Methods: We analyzed the National Inpatient Sample (NIS) from 2017–2023. CAR-T therapy was identified using ICD-10-PCS procedure codes in any procedure field. The primary cohort included hospitalizations with a principal diagnosis of lymphoma or leukemia (ICD-10-CM C81–C86, C88, C90, C91–C95). Outcomes included in-hospital mortality, length of stay (LOS), and total hospital charges. Survey-weighted analyses accounted for clustering and stratification, with variance estimation using Taylor linearization at the hospital level. Stratified analyses were performed for lymphoma and leukemia admissions. Results: National inpatient CAR-T volume increased from 805 admissions in 2017 to 5,845 in 2021, with 4,310 admissions in 2023. In pooled analyses of lymphoma and leukemia admissions, CAR-T therapy was not associated with higher in-hospital mortality compared with non-CAR-T admissions (risk difference −0.36%, 95% CI −1.35% to 0.62%). CAR-T admissions were associated with significantly longer LOS (+15.0 days, 95% CI 14.0–16.1) and higher hospital charges (+$365,563, 95% CI $331,158–$399,968). In stratified analyses, CAR-T therapy was associated with lower inpatient mortality among lymphoma admissions (risk difference −4.66%, 95% CI −5.05% to −4.26%), while no mortality difference was observed among leukemia admissions. Increased LOS and hospital charges were observed in both strata. Conclusions: In a contemporary national cohort, inpatient CAR-T utilization expanded substantially following regulatory approval and was associated with markedly increased inpatient resource utilization. Inpatient mortality was not increased overall compared with non-CAR-T admissions, with important heterogeneity by diagnosis group. These findings provide real-world context for inpatient CAR-T delivery and may inform future strategies to optimize care pathways and resource allocation.