Did California’s 2020 Medi-Cal Expansion Improve Health Insurance Coverage and Mental Health Outcomes Among Young Adults Without US Citizenship? A Population-based, Quasi-Experimental Study

Thesis (Master's)--University of Washington, 2023 ; Background: In 2020, California became one of the first states to expand Medicaid (Medi-Cal) to low-income young adults, irrespective of US citizenship. The primary aim of this study was to assess whether California's 2020 Young Adult Medi-Cal expansion improved healthcare access and mental health outcomes among low-income (<200% Federal Poverty Line) young adults aged 18-25 who lacked US citizenship. Methods: This study used a quasi-experimental design to analyze repeated cross-sectional data from the 2016-2021 waves of the California Health Interview Survey (CHIS). A difference-in-difference regression was used to estimate the impact of coverage expansion on health insurance coverage, healthcare access, and mental health outcomes. Outcomes were compared between a treatment group of low-income young adults without US citizenship (n=522) and a control group of low-income young adults with US citizenship (n=3,585), before and after the coverage expansion. Results: The present study found evidence of persistent disparities in insurance coverage and healthcare access for low-income young adults in California without US citizenship, who had lower rates of any coverage and measures of healthcare access relative to young adults with US citizenship. The 2020 Medi-Cal expansion was associated with an additional 10 percentage-point increase in private health insurance coverage for young adults without US citizenship (95% CI: 1% 19%) and an additional 12 percentage-point increase in access to a usual source of care (95% CI: 2%, 21%), relative to those with US citizenship. This analysis found no significant difference for any coverage or Medi-Cal coverage associated with the expansion, although Medi-Cal coverage appeared to decline by 8 percentage points for those without US citizenship (95%CI: -18%, 3%), relative to those with US citizenship. Both groups of young adults saw increases in the prevalence of serious psychological distress over the study period. ...