The impact of individual-level income predicted from the BRFSS on the association between insurance status and overall survival among adults with cancer from the SEER program

Introduction: Among patients with cancer in the United States, Medicaid insurance is associated with worse outcomes than private insurance and with similar outcomes as being uninsured. However, prior studies have not addressed the impact of individual-level socioeconomic status, which determines Medicaid eligibility, on the associations of Medicaid status and cancer outcomes. Our objective was to determine whether differences in cancer outcomes by insurance status persist after accounting for individual-level income.

Methods: The Surveillance, Epidemiology, and End Results (SEER) database was queried for 18-64 year-old individuals with cancer from 2014-2016. Individual-level income was imputed using a model trained on Behavioral Risk Factors Surveillance Survey participants including covariates also present in SEER. The association of 1-year overall survival and insurance status was estimated with and without adjustment for estimated individual-level income and other covariates.

Results: A total of 416,784 cases in SEER were analyzed. The 1-yr OS for patients with private insurance, Medicaid insurance, and no insurance was 88.7%, 76.1%, and 73.7%, respectively. After adjusting for all covariates except individual-level income, 1-year OS differences were worse with Medicaid (-6.0%, 95% CI = -6.3 to -5.6) and no insurance (-6.7%, 95% CI = -7.3 to -6.0) versus private insurance. After also adjusting for estimated individual-level income, the survival difference for Medicaid patients was similar to privately insured (-0.4%, 95% CI = -1.9 to 1.1) and better than uninsured individuals (2.1%, 95% CI = 0.7 to 3.4).

Conclusions: Income, rather than Medicaid status, may drive poor cancer outcomes in the low-income and Medicaid-insured population. Medicaid insurance coverage may improve cancer outcomes for low-income individuals.