Effects Of The ACA's Health Insurance Marketplaces On The Previously Uninsured: A Quasi-Experimental Analysis.

Descriptive studies have suggested that the Affordable Care Act's (ACA's) health insurance Marketplaces improved access to care. However, no evidence from quasi-experimental studies is available to support these findings. We used longitudinal survey data to compare previously uninsured adults with incomes that made them eligible for subsidized Marketplace coverage (138-400 percent of the federal poverty level) to those who had employer-sponsored insurance before the ACA with incomes in the same range. Among the previously uninsured group, the ACA led to a significant decline in the uninsurance rate, decreased barriers to medical care, increased the use of outpatient services and prescription drugs, and increased diagnoses of hypertension, compared to a control group with stable employer-sponsored insurance. Changes were largest among previously uninsured people with incomes of 138-250 percent of poverty, who were eligible for the ACA's cost-sharing reductions. Our quasi-experimental approach provides rigorous new evidence that the ACA's Marketplaces led to improvements in several important health care outcomes, particularly among low-income adults.