Immunotherapy-Related Adverse Events and Clinical Outcomes in Adult Solid-Tumor Patients Admitted to an Onco-Hospitalist Medicine Service.

: Few studies have focused on patients with immune-related adverse events (irAEs) after immune checkpoint inhibitor (ICI) treatment who were cared for primarily by hospitalists. The objective of our study was to describe the patterns and outcomes of adult solid-tumor cancer patients admitted to our onco-hospital medicine service. : We retrospectively reviewed patients with solid tumors who received ICIs and were admitted to our service in 2021-2022 with an irAE and compared them to a control group (IOTOX vs. NO IOTOX, respectively). The primary outcome was the patterns of irAEs requiring hospitalization; secondary outcomes included 30-day emergency room visit, readmission, and 30-day mortality. : There were 144 patients in the IOTOX group and 286 controls. The most common tumor type was lung and thoracic malignancies (62, 43.1%). The most common ICI causing the irAEs was pembrolizumab (66, 45.8%). The most common irAEs were pneumonitis (49, 34%), colitis (28, 19.4%), hepatitis (18, 12.5%), and myocarditis (16, 11.1%). Of the 144 patients, eight (6%) died from the hospitalization irAE. Fifteen (15.6%) had an ER visit within 30 days due to the same irAE, and thirteen (13.7%) were readmitted. Survival at 30 days after discharge did not differ significantly between groups. : Despite many patients having severe irAEs and irAEs associated with higher mortality, they generally had a favorable outcome compared to the literature.