Factors accounting for excess uterine cancer mortality among insured Black versus White patients treated within the same US health care system

OBJECTIVE: This study aimed to assess factors contributing to the survival disparity between insured Black and White patients with uterine cancer treated within the same large US health care system. METHODS: This is a retrospective cohort analysis of Black and White patients diagnosed with uterine cancer from 2005 to 2022 while members of a large community-based integrated US health care system. Five domains of factors potentially contributing to survival were characterized: co-morbidities, diagnostic process, treatment, tumor characteristics, and socioeconomic factors. Using logistic regression, propensity scores were calculated and used to sequentially balance Black and White patients for each of these domains, evaluating the effect of balancing each domain on the hazard ratio (HR) for 5-year mortality for Black versus White patients. RESULTS: Comparing 11,878 White with 2196 Black patients, the HR for 5-year mortality for Black patients, adjusted for baseline characteristics and co-morbidities, was 2.05 (95% confidence interval CI 1.79 to 2.33). Substantial reductions in excess mortality were observed after balancing tumor factors, which reduced the HR to 1.31 (95% CI 1.11 to 1.53), and socioeconomic factors, which further reduced the HR to 1.08 (95% CI 0.91 to 1.28). No significant reduction was observed after balancing co-morbidity, diagnostic, or treatment factors. CONCLUSIONS: Among insured patients treated within the same US health care system, Black patients had approximately twice the mortality risk of White patients, with 70.8% of the excess relative risk of death among Black patients being attributable to tumor characteristics, 21.4% attributable to socioeconomic status, and 7.8% un-explained. Co-morbidities, diagnostic efficiency, and treatment quality were not significant contributors relative to other factors. These findings suggest that eliminating disparities in survival between Black and White patients will require development of more effective treatments for high-risk tumor types and interventions that mitigate the negative effects of lower socioeconomic status on health.