Inpatient chemotherapy and immunotherapy encounters in the United States: Recent trends, acute complications, and palliative care utilization.

Abstract

e23144 Background: Most chemotherapy and immunotherapy treatments are administered in the ambulatory setting, while inpatient systemic therapies are often reserved for high-acuity and complex cases. National data on inpatient chemotherapy and immunotherapy hospitalizations in the modern immunotherapy era remain limited. We aimed to examine acute severe inpatient complications, palliative care utilization, and outcomes among hospitalizations with chemotherapy and immunotherapy. Methods: We conducted a retrospective study using the National Inpatient Sample (NIS) from 2016 to 2022. Hospitalizations with a diagnosis indicating inpatient chemotherapy (Z51.11) and/or immunotherapy encounter (Z51.12) were queried. Acute inpatient complications were identified using ICD-10 codes. Survey-weighted descriptive analyses and multivariable survey-weighted regression models were performed. Results: The cohort included 190,676 unweighted admissions representing around 953,380 weighted hospitalizations, with an average age of 41.5 years old and average length of stay (LOS) 5.9 days. 61.8% of encounters were hematologic malignancies and 35.2 % were solid organ malignancies. Encounter type distribution was chemo-only 96.1%, immune-only 2.50%, and both 1.45%. There was a steady increase in immunotherapy encounters since 2018 with 12.54% of the hospitalizations of 2018 compared to 20.92% in 2022. There was low incidence of sepsis (1.74%), acute respiratory failure (ARF, 1.54%), tumor-lysis syndrome (TLS, 1.19%). Acute kidney injury (AKI, 5.66%). Septic shock (0.55%), ventricular fibrillation/ventricular tachycardia (0.36%), cardiac arrest (0.01%), and death (0.62%) were rare events. Inpatient palliative care use occurred in 2.35% of these hospitalizations. In weighted multivariate regression analyses of palliative care utilization, acute inpatient complications were the strongest independent predictors. Palliative care use was significantly associated with sepsis (OR 4.44, 95% CI 3.83–5.14), AKI (OR 2.25, 95% CI 2.04–2.49), TLS (OR 2.04, 95% CI 1.69–2.47), and catastrophic cardiovascular events (OR 1.57, 95% CI 1.17–2.11). In adjusted log-linear models, palliative care involvement was associated with an 18% longer LOS (95% CI 14%–22%) and 35% higher total hospital charges (95% CI 30%–40%, both p < 0.001), likely reflecting greater illness severity among patients receiving palliative care. Conclusions: Inpatient chemotherapy and immunotherapy hospitalizations represent a high-acuity population with infrequent but severe complications, in which palliative care utilization remains uncommon and is primarily driven by acute severe clinical complications. These findings highlight opportunities for earlier palliative integration and improved risk stratification in hospitalized patients receiving systemic cancer therapies.