The effect of Medicaid expansion among adults from low-income communities on stage at diagnosis in those with screening-amenable cancers.

BACKGROUND: Several states have opted to expand Medicaid under the Patient Protection and Affordable Care Act (ACA), which offers insurance coverage to low-income individuals up to 138% of the federal poverty level. This expansion of Medicaid to a medically vulnerable population potentially can reduce cancer outcome disparities, especially among patients with screening-amenable cancers. The objective of the current study was to estimate the effect of Medicaid expansion on the percentage of adults from low-income communities with screening-amenable cancers who present with metastatic disease.

METHODS: Using state cancer registry data linked with block group-level income data, a total of 12,760 individuals aged 30 to 64 years who were diagnosed with incident invasive breast (female), cervical, colorectal, or lung cancer from 2011 through 2016 and who were uninsured or had Medicaid insurance at the time of diagnosis were identified. This sample was probability weighted based on income to reflect potential Medicaid eligibility under the ACA's Medicaid expansion. A multivariable logistic model then was fitted to examine the independent association between the exposure (pre-expansion [years 2011-2013] vs postexpansion [years 2014-2016]) and the outcome (metastatic vs nonmetastatic disease at the time of diagnosis).

RESULTS: After adjusting for potential confounders, individuals who were diagnosed postexpansion were found to have 15% lower odds of having metastatic disease compared with those who were diagnosed pre-expansion (adjusted odds ratio, 0.85; 95% confidence interval, 0.77-0.93). As a control, a separate analysis that focused on individuals with private insurance who resided in high-income communities found nonsignificant postexpansion (vs pre-expansion) changes in the outcome (adjusted odds ratio, 1.02; 95% confidence interval, 0.96-1.09).

CONCLUSIONS: Medicaid expansion is associated with a narrowing of a critical cancer outcome disparity in adults from low-income communities.