Medicaid expansion under ACA linked with better health care for low-income adults

The study will be published August 8, 2016 in JAMA Internal Medicine.

The researchers found similar benefits for residents in Kentucky -- which expanded using Medicaid managed care -- and Arkansas -- which used federal Medicaid funding to subsidize private insurance, the so-called "private option."

"What this means is that it doesn't matter so much how states expand coverage," said lead author Benjamin Sommers, assistant professor of health policy and economics at Harvard Chan School and assistant professor of medicine at Harvard Medical School. "What matters is whether they expand at all."

So far, more than 30 states and the District of Columbia have chosen to expand coverage under the ACA. In numerous states the debate over expansion continues and in Arkansas and Kentucky, newly elected governors have proposed scaling back or overhauling their expansions.

Sommers and colleagues surveyed approximately 9,000 low-income adults in Arkansas, Kentucky, and Texas from late 2013 to the end of 2015. The results showed that, between 2013 and 2015, the uninsured rate dropped from 42% to 14% in Arkansas and from 40% to 9% in Kentucky, compared with a much smaller change in Texas (39% to 32%). Expansion also was associated with significantly increased access to primary care, improved affordability of medications, reduced out-of-pocket spending, reduced likelihood of emergency department visits, and increased outpatient visits. Screening for diabetes, glucose testing among people with diabetes, and regular care for chronic conditions all increased significantly after expansion. Quality of care ratings improved significantly, as did the number of adults reporting excellent health.

Many of these changes were more apparent in 2015 than in 2014. Previous studies looking at the early impact of Medicaid expansion had shown increased affordability and access to care, but limited impact on utilization, preventive care, and health. Sommers said those studies probably underestimated the ACA's impact because they were using data from just the first year or 18 months of coverage and it may be that the benefits of expansion take longer to unfold.

"Health insurance matters to people's health," Sommers said. "Our study shows that with health insurance, whether it's Medicaid or private coverage, people can better afford their medical care, get more preventive care and chronic disease management, and ultimately achieve better overall health."