The Consequences of the Affordable Care Act Medicaid Expansions on Coverage, Utilization, Access, and Health

In 2014, only 26 states and D.C. chose to participate in the Affordable Care Act (ACA) Medicaid expansions for low-income adults. In this study, we estimate the effect of the state ACA Medicaid expansions on insurance coverage, access to and utilization of health care, and self-reported health using the 2010-2014 National Health Interview Survey. We compare changes in outcomes for low-income adults before and after the 2014 expansions in states that did and did not expand Medicaid using a difference-in-differences design. We find that the Medicaid expansions were associated with increased health insurance (8.0 percentage points; 95% CI, -11.3 to -4.6) and Medicaid coverage (9.8 percentage points; 95% CI, 6.2 to 13.3), and increased self-reported quality of insurance coverage compared to a year ago (8.6 percentage points; 95% CI, 4.6 to 12.5). Expansions increased visits with doctors in general practice (5.5 percentage points; 95% CI, 0.4 to 10.5), decreased respondent reports of no usual place of medical care due to cost or lack of insurance (4.5 percentage points; 95% CI, -7.7 to -1.3), and increased rates of diagnosis of diabetes (4.5 percentage points; 95% CI, 1.6 to 2.4) and high cholesterol (5.2 percentage points; 95% CI, 1.4 to 9.0). We conclude that the ACA Medicaid expansions were associated with substantially higher rates of insurance coverage, improved quality of coverage, increased utilization of some types of health care, and higher rates of diagnosis of chronic health conditions for low-income adults.