Impacts of the Affordable Care Act Medicaid Expansion in California

Abstract

We examined the impact of the Affordable Care Act (ACA) on healthcare coverage, access, health status, and affordability, as well as disparities in these outcomes by race/ethnicity among low-income Californians. We used nationally representative survey data from the Behavioral Risk Factor Surveillance Survey 2011-2019 and a difference-in-differences approach that compared California with nonexpansion states. We examined the impact of Medicaid expansion on health insurance coverage, having a usual source of care, self-reported health status, frequent (≥14) unhealthy days in the past month (physical, mental, and both), and foregone care due to cost. The sample population included low-income Californians (<100% of the federal poverty guidelines) aged 19-64 and low-income childless adults. Low-income adults, childless adults, and white childless adults in California saw post-ACA gains in six of seven outcomes, including a 7.7 percentage point increase in having a usual source of care for all low-income adults (CI: 0.051 to 0.104). Childless adult people of color (POC) reported significant improvements in three measures, with a 6.6 percentage point increase in having a usual source of care (CI: 0.013 to 0.120). All of the groups we examined had coverage gains, ranging from 3.9 percentage points for all low-income adults (CI: 0.013 0.066) to 8.4 percentage points for white childless adults (CI: 0.025 to 0.143). Additionally, all groups reported improved mental health, including an 8.2 percentage point decrease in frequent mental distress for childless adults (CI: -0.120 to -0.044). These findings indicate that the ACA coverage expansion benefitted the targeted population of low-income Californians. Additionally, the disparity between white and non-white Californians decreased for the unadjusted mean rate of having a usual source of care. However, unadjusted means showed that white low-income adults remained more likely to have health insurance coverage and a usual source of care compared with POC in both California and nonexpansion states.