The impact of the Affordable Care Act Medicaid Expansion in Medicare beneficiaries with peripheral artery disease

Background: In 2014, the Affordable Care Act Medicaid Expansion (ME) increased Medicaid eligibility for adults with an income level up to 138% of the federal poverty level. In this study, we examined the impact of ME on mortality and amputation in patients with peripheral artery disease (PAD). Methods: The 100% MedPAR and Part-B Carrier files from 2011 to 2018 were queried to identify all fee-for-service Medicare beneficiaries with PAD using International Classification of Diseases codes. Our primary exposure was whether a state had adopted the ME on January 1, 2014. Our primary outcomes were the change in all-cause 1-year mortality and leg amputation. We used a state-level difference-in-differences (DID) analysis to compare the rates of the primary outcomes among patients who were in states (including the District of Columbia) who adopted ME (n = 25) versus those who were in states that did not (n = 26). We performed a subanalysis stratifying by sex, race, region, and dual-eligibility status. Results: Over the 8-year period, we studied 37,743,929 patients. The average unadjusted 1-year mortality decreased from 2011 to 2018 in both non-ME (9.5% to 8.7%, p < 0.001) and ME (9.1% to 8.3%, p < 0.001) states. The average unadjusted 1-year amputation rate did not improve in either the non-ME (0.86% to 0.87%, p = 0.17) or ME (0.69% to 0.69%, p = 0.65) states. Across the entire cohort, the DID model revealed that ME did not lead to a significant change in mortality (p = 0.15) or amputation (p = 0.34). Conclusion: Medicaid Expansion was not associated with reduced mortality or leg amputation in Medicare beneficiaries with PAD.