Competing mortality risk from COVID-19, cerebrovascular diseases, and ischemic heart disease among U.S. cancer patients by race, income, and rurality

This study examined competing risks of mortality from COVID-19, cerebrovascular disease (CVD), and ischemic heart disease (IHD) among cancer patients, concentrating on disparities by race, median household income (MHI), and rural-urban continuum codes (RUCC). A retrospective cohort of 333,966 cancer patients from the SEER data was analyzed. Cumulative incidence and competing risk regression models estimated covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for cause-specific mortality, and interaction effects were evaluated. The cohort recorded 1,581 (0.47%) deaths from COVID-19, 881 (0.26%) from CVD, and 2126 (0.64%) from IHD. COVID-19 mortality was disproportionately higher among American Indian/Alaskan Native and Black cancer patients, while IHD was most prominent in Asian and White groups. Higher income was protective: patients earning >$100K had a 62% lower COVID-19 mortality risk than those earning <$70K (HR: 0.38, 95% CI: 0.32–0.47). Similar, but smaller reductions were observed for IHD mortality; CVD patterns were less consistent. Geographic disparities were evident: RUCC 3 patients had lower mortality from COVID-19 (HR: 0.66, 95% CI: 0.52–0.83), CVD (HR: 0.72, 95% CI: 0.53–0.98), and IHD (HR: 0.76, 95% CI: 0.62–0.93) than RUCC 1. RUCC 4 and 5 showed reduced CVD mortality but no significant differences for COVID-19 or IHD. Interaction analyses showed higher CVD mortality for higher-income patients in RUCC 3, while income was protective for IHD mortality in RUCC 2, 4, and 5 (HRs: 0.44–0.52). The study revealed disparities in cancer survival and cause-specific mortality by race, income, and geography. Findings help identify vulnerable cohorts for targeted policy measures, interventions, and future research.