A real-world cohort study of immune-related adverse events in patients receiving immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have transformed cancer care but are frequently associated with immune-related adverse events (irAEs), complicating treatment. This retrospective cohort study analyzed 9193 adult patients from the OneFlorida+ Clinical Research Network who received ICIs between 2018 and 2022, aiming to identify risk factors for irAEs and evaluate their incidence, severity, and clinical impact. Among the 6,526 patients included in the final analysis, 56.2% developed irAEs within 1 year, including 284 hospitalized cases. Multivariable logistic regression revealed that younger age (18-29), female sex, and comorbidities such as myocardial infarction, heart failure, and renal disease increased irAE risk, while dementia and recent chemotherapy were associated with lower risk. Patients receiving CTLA-4 + PD(L)1 combination therapy had a 35% higher risk of irAEs than those treated with PD-1 inhibitors alone. Breast and hematologic cancers conferred elevated risk, whereas brain cancer was linked to reduced risk. Kaplan-Meier and cumulative incidence analyses demonstrated that irAE severity significantly impacted time to onset (P = 0.038), and overall survival was worse in patients who developed irAEs (P < 0.0001). Treatment regimen influenced irAE-free survival in multi-site cancers and overall survival in kidney cancer, highlighting the need for tailored irAE risk stratification.