Long-Term Impact of Medicaid Expansion on Colorectal Cancer Screening in Its Targeted Population

INTRODUCTION: Colorectal cancer screening continuously decreased its mortality and incidence. In 2010, the Affordable Care Act extended Medicaid eligibility to low-income and childless adults. Some states elected to adopt Medicaid at different times while others chose not to. Past studies on the effects of Medicaid expansion on colorectal cancer screening showed equivocal results based on short-term data following expansion. AIMS: To examine the long-term impact of Medicaid expansion on colorectal cancer screening among its targeted population at its decade mark. METHODS: Behavioral Risk Factor Surveillance System data were extracted for childless adults below 138% federal poverty level in states with different Medicaid expansion statuses from 2012 to 2020. States were stratified into very early expansion states, early expansion states, late expansion states, and non-expansion states. Colorectal cancer screening prevalence was determined for eligible respondents. Difference-in-differences analyses were used to examine the effect of Medicaid expansion on colorectal cancer screening in states with different expansion statuses. RESULTS: Colorectal cancer screening prevalence in very early, early, late, and non-expansion states all increased during the study period (40.45% vs. 48.14%, 47.52% vs 61.06%, 46.06% vs 58.92%, and 43.44% vs 56.70%). Difference-in-differences analysis showed significantly increased CRC screening prevalence in very early expansion states during 2016 compared to non-expansion states (Crude difference-in-differences + 16.45%, p = 0.02, Adjusted difference-in-differences + 15.9%, p = 0.03). No statistical significance was observed among other years and groups. CONCLUSIONS: Colorectal cancer screening increased between 2012 and 2020 in all states regardless of expansion status. However, Medicaid expansion is not associated with long-term increased colorectal cancer screening prevalence.