ANN ARBOR—States that participated in Medicaid expansion under the Affordable Care Act saw increased insurance rates and access to care, less worry about paying medical bills, but also longer wait times among low-income residents, according to new research.

In a study published in the New England Journal of Medicine, Sarah Miller of the University of Michigan and Laura Wherry of the University of California, Los Angeles, analyze survey data from states that participated in the Medicaid expansion and states that declined.

The study comes as Congress debates a proposed replacement of the Affordable Care Act.

The researchers found uninsurance rates dropped in the expansion states in year two by 8.2 percentage points and Medicaid coverage increased 15.6 percentage points among low-income residents when compared with non-expansion states.

Though expansion wasn’t associated with significant changes in health status, expansion states saw an increase in the ability to afford followup care for low-income residents—3.4 percentage points compared with non-expansion states—and fewer reports of worry about paying medical bills—a decrease of 7.9 percentage points compared with non-expansion states.

“These results suggest that any proposed cuts to the ACA Medicaid expansions would substantially reduce access to health care for low-income individuals,” said Miller, assistant professor of business economics and public policy.

Miller and Wherry also found that expansion states reported increases in medical care delays due to wait times for low-income residents—a 2.6 percentage-point increase over non-expansion states. By September 2015, 29 states and Washington, D.C., participated in the Medicaid expansion.

Miller and Wherry compared changes in outcomes two years after the Medicaid expansion—2014 and 2015—relative to the four years before it. They used data from the National Health Interview Survey and compared results from the expansion and non-expansion states. The survey sample was 60,766 U.S. citizens between 19-64 years of age who had incomes below 138 percent of the federal poverty level.

More information:

• Sarah Miller