Immune checkpoint inhibitor exposure and outcomes of gastrointestinal bleeding in cancer patients: a national analysis of 130,557 hospitalizations, 2018-2022.

Background: Although immune checkpoint inhibitors (ICIs) have transformed cancer treatment, they are associated with immune-related adverse events, including gastrointestinal (GI) toxicity. While GI bleeding is a common cause of hospitalization among cancer patients, the relationship between ICI exposure and the outcomes of GI bleeding at the national level remains unclear. Methods: This retrospective cohort study utilized data from the National Inpatient Sample (NIS) between 2018 and 2022. Adult cancer patients hospitalized with GI bleeding were identified and stratified by ICI exposure. The primary outcome was in-hospital mortality. Secondary outcomes included colectomy, intensive care unit (ICU) admission, and blood transfusion. Survey-weighted logistic regression models, adjusted for demographics, insurance, income, admission type, and year, were employed. Sensitivity analyses included adjustments for Elixhauser comorbidities, inverse probability of treatment weighting (IPTW), propensity score matching, exclusion of records with inpatient antineoplastic chemotherapy codes, exclusion of records from pandemic years, and alternative ICU-proxy thresholds. Results: Of the 130,557 hospitalizations, 33,130 (25.4%) involved ICI exposure. ICI exposure was associated with significantly lower in-hospital mortality (adjusted odds ratio [aOR] 0.57, 95% confidence interval [CI] 0.54-0.60, Conclusion: ICI exposure was associated with significantly lower in-hospital mortality, colectomy, and ICU admission among cancer patients hospitalized with GI bleeding. These findings likely reflect selection bias, as ICI-treated patients may represent a healthier subpopulation of cancer patients. Further studies incorporating detailed clinical data are needed to elucidate the mechanisms underlying these associations.