Changes in Health Care Access, Behaviors, and Self-reported Health Among Low-income US Adults Through the Fourth Year of the Affordable Care Act.

BACKGROUND: Health care access increased for low-income Americans under the Affordable Care Act (ACA). It is unknown whether these changes in access were associated with improved self-reported health.
OBJECTIVE: Determine changes in health care access, health behaviors, and self-reported health among low-income Americans over the first 4 years of the ACA, stratified by state Medicaid expansion status.
DESIGN: Interrupted time series and difference-in-differences analysis.
SUBJECTS: Noninstitutionalized US adults (18-64 y) in low income households (<138% federal poverty level) interviewed in the Behavioral Risk Factor Surveillance System 2011-2017 (N=505,824). MEASURES: Self-reported insurance coverage, access to a primary care physician, avoided care due to cost; self-reported general health, days of poor physical health, days of poor mental health days, and days when poor health limited usual activities; self-reported health behaviors, use of preventive services, and diagnoses.
RESULTS: Despite increases in access, the ACA was not associated with improved physical or general health among low-income adults during the first 4 years of implementation. However, Medicaid expansion was associated with fewer days spent in poor mental health (-1.1 d/mo, 95% confidence interval: -2.1 to -0.5). There were significant changes in specific health behaviors, preventive service use, and diagnosis patterns during the same time period which may mediate the relationship between the ACA rollout and self-reported health.
CONCLUSION: In nationally-representative survey data, we observed improvements in mental but not physical self-reported health among low-income Americans after 4 years of full ACA implementation.