The impact of Medicaid expansion on spending and utilization by older low‐income Medicare beneficiaries

OBJECTIVE: To examine indirect spillover effects of Affordable Care Act (ACA) Medicaid expansions to working‐age adults on health care coverage, spending, and utilization by older low‐income Medicare beneficiaries. DATA SOURCES: 2010–2018 Health and Retirement Study survey data linked to annual Medicare beneficiary summary files. STUDY DESIGN: We estimated individual‐level difference‐in‐differences models of total spending for inpatient, institutional outpatient, physician/professional provider services; inpatient stays, outpatient visits, physician visits; and Medicaid and Part A and B Medicare coverage. We compared changes in outcomes before and after Medicaid expansion in expansion versus nonexpansion states. DATA COLLECTION/EXTRACTION METHODS: The sample included low‐income respondents aged 69 and older with linked Medicare data, enrolled in full‐year traditional Medicare, and residing in the community. PRINCIPAL FINDINGS: ACA Medicaid expansion was associated with a 9.8 percentage point increase in Medicaid coverage (95% CI: 0.020–0.176), a 4.4 percentage point increase in having any institutional outpatient spending (95% CI: 0.005–0.083), and a positive but statistically insignificant 2.4 percentage point change in Part B enrollment (95% CI: −0.003 to 0.050, p = 0.079). CONCLUSIONS: ACA Medicaid expansion was associated with more institutional outpatient spending among older low‐income Medicare beneficiaries. Increased care costs should be weighed against potential benefits from increased realized access to care.