Racial and ethnic disparities in hospital mortality among cancer patients admitted to the intensive care unit: A retrospective analysis of the MIMIC-IV database.

347 Background: Black patients with cancer face higher mortality rates than White patients across most malignancies, yet whether these disparities extend to the intensive care unit (ICU) setting remains poorly characterized. Prior ICU disparity studies have largely examined general critical care populations without accounting for cancer-specific factors such as tumor type and metastatic burden. We examined racial and ethnic disparities in ICU outcomes among cancer patients and assessed whether disparities differ by cancer type. Methods: We conducted a retrospective cohort study of adult cancer patients with ICU admissions in the MIMIC-IV database (v3.1; 2008-2022). Cancer diagnoses were identified using ICD-9/10 codes and classified as solid or hematologic. The primary outcome was hospital mortality. Sequential logistic regression models adjusted for demographics, insurance, cancer type, illness severity (SOFA, Charlson index), and admission characteristics, with White patients as the reference group. Stratified analyses were performed by cancer type and specific cancer site. Results: Among 14,399 ICU admissions, 72.3% were White, 9.7% Black, 4.4% Asian, and 3.0% Hispanic. Black patients were younger, had higher comorbidity burden, and were more likely to carry Medicaid insurance. Hospital mortality was 22.9% for Black vs 18.5% for White patients. In fully adjusted models, Black patients had persistently higher odds of hospital mortality (Table 1). The disparity was driven by solid tumors (OR 1.31; 95% CI 1.10-1.55; P=0.002) and absent in hematologic malignancies (OR 1.01; P=0.95). Prostate cancer showed the largest site-specific disparity (OR 2.26; 95% CI 1.32-3.88; P=0.003). Black patients had lower mechanical ventilation rates (23.8% vs 26.2%) and lower DNR/DNI documentation (6.5% vs 8.0%) despite higher mortality. Results were robust across five sensitivity analyses. Conclusions: Black patients with cancer admitted to the ICU had significantly higher hospital mortality than White patients even after comprehensive adjustment. This disparity was concentrated in solid tumors and was most pronounced in prostate and pancreatic cancers. The combination of higher mortality with lower intervention rates and less advance care planning documentation among Black patients warrants further investigation into potential mechanisms including treatment intensity differences and systemic care delivery inequities. Adjusted ORs for hospital mortality, Black vs White (sequential models). Model OR (95% CI) P-value Race only 1.31 (1.14-1.50) <0.001 +Demographics 1.34 (1.17-1.54) <0.001 +Insurance 1.33 (1.16-1.52) <0.001 +Cancer type 1.34 (1.17-1.54) <0.001 +Severity (SOFA, CCI) 1.28 (1.10-1.48) 0.001 +Admission characteristics 1.18 (1.01-1.36) 0.034