Clinical, cardiovascular, and inflammatory factors associated with recorded all-cause mortality in hospitalized patients with breast cancer: a retrospective single-center study

Objective This study evaluated the associations of systemic immune-inflammation index (SII) and cumulative cardiovascular burden with recorded all-cause mortality in hospitalized patients with breast cancer, and explored whether SII added information beyond clinical and oncological factors. The retrospective single-center cohort included 428 patients hospitalized between September 2023 and December 2025. Vital status was available for 427 patients and was ascertained on 20 June 2026. Results description Among the 427 patients with available vital status, 39 (9.1%) were recorded as deceased. In multivariable analysis, older age (OR 1.09 per year, 95% CI 1.05–1.13) and stage IV versus stage I disease (OR 3.41, 95% CI 1.12–10.38) were associated with recorded all-cause mortality status. Cardiovascular burden (OR 1.12, 95% CI 0.84–1.50) and SII (OR 0.79 per 1000 units, 95% CI 0.42–1.50) were not statistically significant. Adding SII did not result in a statistically detectable improvement in model fit. Sensitivity analyses accounting for potential observation duration showed similar results. Because exact dates of death were unavailable, the findings reflect recorded mortality status rather than survival or longitudinal mortality risk.