Rehospitalization following immune-related adverse events from immune checkpoint inhibitors: A retrospective chart review.

372 Background: Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy for various malignancies by enhancing the immune system's ability to target tumors. Use of ICI can result in immune-related adverse events (irAEs), causing significant morbidity and hospitalizations. A multidisciplinary approach for management may improve patient outcomes. Methods: We retrospectively reviewed electronic medical record data from patients who received ICIs in the Brown University Health (BUH) system 2015-2024 to identify the most common toxicities resulting in hospitalizations and rehospitalizations. Outcomes assessed include type of irAE, placement of inpatient subspecialty consult, length of hospitalization, outpatient oncology follow-up, and rehospitalizations. Risk factors associated with rehospitalization were analyzed with the Mann-Whitney U test for continuous data and Fisher’s exact test for categorical data. Results: Of 2723 patients, 652 developed an irAE. irAEs that most often lead to hospitalization were colitis (43/103), pneumonitis (31/69), nephritis (16/37), and adrenal insufficiency (10/30). Out of the 100 patients admitted for one of these irAEs, 21 were re-hospitalized for the same toxicity: colitis (7/43, 16%), pneumonitis (8/31, 26%), nephritis (2/16, 13%), and adrenal insufficiency (4/10, 40%). During the first admission, 12 patients died or transitioned to hospice and were omitted from statistical analysis. Overall, the median number time to hospital re-admission was 18 days (range 1 day- 3.9 years). The median length of first hospitalization had no impact on the chance of subsequent hospitalization (P = .497). Early outpatient hematology-oncology follow-up, defined as a clinic visit within 7 days of discharge, did not lead to a statistically significant decrease in re-hospitalizations (P = 0.137). However, hospitalized patients that received a subspecialist consultation within 48 hours of admission were 3.7 times less likely to be re-hospitalized compared to patients who received an inpatient consultation after 48 hours or did not receive one (OR: 0.27, P = 0.0229). Conclusions: These findings highlight the importance of early recognition and interdisciplinary management of irAEs to mitigate the risk of complications and improve outcomes. Early subspeciality consult may be linked to decreased readmissions. Admissions for adrenal insufficiency deserve particular attention given the high proportion of rehospitalizations. Recent steps to help decrease hospitalizations within BUH include designating specialists for each toxicity and initiating a monthly interdisciplinary immune-related tumor board.