A new study finds that coverage expansion under the Affordable Care Act (ACA) has been particularly beneficial to low-income adults.

For the study, published in Health Affairs, researchers from Harvard T.H. Chan School of Public Health reviewed the effects of expanded health coverage availability to low-income adults under the ACA. They examined outcomes in three states: Kentucky, which expanded Medicaid; Arkansas, which expanded private insurance to low-income adults using the federal health insurance marketplace; and Texas, which did not expand coverage in either way.

Using telephone surveys of low-income adults from 2013–2016, the researchers found that all three states began 2014 with similar pre-ACA uninsured rates of about 40 percent. After ACA-related coverage expansion took effect, uninsured rates dropped steeply in Kentucky and Arkansas and continued to drop steadily in the following years. Overall, health coverage among low-income adults in Kentucky and Arkansas increased by 14 percentage points in 2014, 22.9 percentage points in 2015, and 20.7 percentage points in 2016. In Texas, the rate fell moderately in 2014 before plateauing. By 2016, Texas had an uninsured rate of 28.2 percent, compared with 7.4 percent in Kentucky and 11.7 percent in Arkansas.

Researchers found that expanding coverage improved access and affordability — low-income adults in Kentucky and Arkansas were less likely to use the emergency department for primary care, were less likely to delay seeking care or skipping medications due to cost, and reported less difficulty paying medical bills. In addition, more respondents reported being in “excellent” health.