Health Care Utilization and Costs for Older Adults Aging Into Medicare After the Affordable Care Act.

Importance: The Affordable Care Act (ACA) expanded Medicaid and Marketplace insurance to nonelderly adults in 2014, but whether these policies improved outcomes later in life is unknown.

Objective: To examine whether exposure to ACA expansions during middle age (50-64 years) was associated with changes in health, utilization, and spending after these adults entered Medicare at 65 years of age.

Design, setting, and participants: This serial analysis of the Health and Retirement Study cohort linked to Medicare enrollment and claims data from January 1, 2010, to December 31, 2018. Adults aged 65 to 68 years entering Medicare after the ACA (exposed to ACA expansions during middle age) were compared with adults entering Medicare before the ACA (4452 person-years). Interrupted time series analyses were used to assess overall changes associated with exposure to ACA expansions and difference-in-differences analyses to isolate changes associated with Medicaid expansion among low-income adults (incomes ≤400% of the federal poverty level for any ACA coverage and ≤138% for Medicaid expansion coverage). Data were analyzed from March 1, 2023, to May 1, 2024.

Exposures: ACA coverage expansion overall in 2014 and Medicaid expansion as of 2018.

Main outcomes and measures: Health (self-reported overall, activities of daily living [ADL], instrumental ADL, and depressive symptoms), utilization (outpatient visits, emergency department visits, and hospital admission), and costs (self-reported out-of-pocket and Medicare costs).

Results: Among the analytic sample of 2782 participants (mean age, 66.4 [95% CI, 66.3-66.5] years), a weighted 59.1% (95% CI, 55.3%-62.7%) were female. In interrupted time series analyses, reductions across cohorts were found in use of chronic disease medications (-5.0 [95% CI, -9.8 to -0.3] percentage points), hospitalizations per year (-0.2 [95% CI, -0.4 to -0.03]), and out-of-pocket costs (-$417 [95% CI, -$694 to -$139]) but no significant changes across cohorts in health status, outpatient or emergency visits, or Medicare costs. In difference-in-differences analyses relative to nonexpansion states, greater reductions were found in the number of ADL limitations (-0.4 [95% CI, -0.8 to -0.02]) and lesser reductions in out-of-pocket costs ($900 [95% CI, $275-$1526]) in Medicaid expansion states but otherwise similar changes in other outcomes.

Conclusions and relevance: This study found modest evidence of reductions in out-of-pocket costs and improvements in health among adults entering Medicare after the ACA. Insurance coverage and financial assistance should be preserved and enhanced to improve health and health care access among vulnerable older adults.