Immune checkpoint inhibitor use and health care utilization in an academic center: A retrospective cohort analysis.

e23171 Background: Immune checkpoint inhibitors (ICIs) are widely used to treat various cancer types. Despite their clinical benefits, the morbidity and mortality associated with immune-related adverse events (irAEs) caused by ICIs are increasing. We conducted a retrospective analysis of patients on ICIs who required emergency department (ED) visits or hospitalizations to evaluate the overall healthcare utilization burden and identify risk factors associated with these encounters. Methods: A retrospective cohort study was conducted at the UCLA Medical Center from 2013 to 2022. Patients who received at least one dose of ICIs were included in the analysis. ICI-associated ED visits and hospital admissions were investigated, and department and specialty utilization patterns were analyzed. Univariate and multivariate analyses were performed to identify risk factors associated with the need for ED visits and hospitalizations. Results: A total of 4,603 patients receiving ICIs were identified across various cancer types between 2013 and 2022. Of these, 2,483 patients (53.9%) required at least one ED visit or inpatient admission, and 1,349 patients (69%) had multiple ED visits, with an average of 3.5 ED presentations and a median of 2 ED presentations per patient. A total of 6,775 ED encounters (64.1%) and 3,526 direct inpatient admissions (33.3%) were observed. Among ED visits, 64% required subsequent admission to inpatient or observation for further management. In multivariate analysis, African Americans (OR 2.72, 95% CI 1.86–4.05), males (OR 1.36, 95% CI 1.21–1.54), and combination anti-CTLA-4/PD-1 therapy (OR 1.26, 95% CI 1.05–1.53) were associated with a significantly increased risk of ED visits or hospitalizations. Additionally, African Americans were at a particularly higher risk of multiple ED or hospital encounters (OR 3.40, 95% CI 2.31–5.10). Conclusions: Patients on ICIs have a high need for ED visits and hospitalizations, with most ED visits requiring further inpatient admission. This study highlights the real-world healthcare utilization burden and significant disparities associated with ICIs.