Cancer
Association between Dual Eligibility and Diagnosis of Distant Stage of Colorectal Cancer (CRC) Among Low-Income Individuals in Urban Areas: An Analysis of SEER-Medicare Claims Data Saif Al Amin* Saif Al Amin Eman Metwally Sharon Peacock Hinton Caroline A. Thompson
Colorectal cancer (CRC) is a major health concern in the United States, with elevated mortality rates and pronounced disparities, particularly among low-income, urban populations. Older adults who are dually eligible Medicare-Medicaid beneficiaries are a particularly vulnerable demographic. Limited research has examined CRC outcomes in this population, especially late stage at diagnosis, which is strongly associated with poor survival. We examined the association of dual eligibility and CRC stage at diagnosis among low-income urban residents in the United States, and whether this association varied by race. We analyzed Surveillance, Epidemiology, and End Results linked Medicare data for individuals aged >65, living in low-income urban areas and diagnosed with primary invasive CRC between 2008-2017, who had 12 months pre-diagnostic continuous enrollment in Medicare (A/B, fee for service). To estimate the association between dual eligibility and late-stage CRC, we used a log-binomial regression model additionally adjusted for age, frailty, and comorbidities. A simple quantitative bias analysis was used to address potential confounding due to nursing home residency status. The analysis included 22,193 patients, 89% were non-Hispanic white, 54% were female, 59% had high frailty scores (>0.15), 92% were dual-eligible and 20% were diagnosed at distant stage. The estimated prevalence ratio (PR) of 1.11 (95% CI: 1.04-1.22) indicates a slightly higher adjusted prevalence of distant-stage CRC among duals compared to their non-dual counterparts. The QBA yielded an upward corrected PR of 1.14. No modification of this association was found by patient race. Despite being eligible for additional medical coverage, our study reveals that dually eligible populations are still at risk for poor CRC outcomes. These insights may be useful for shaping effective strategies and interventions to reduce the impact of CRC outcomes in vulnerable populations.