Expanding Medicaid-benefit eligibility to cover all people with income up to 138 percent of the federal poverty line reduced Black-white disparities in preventable hospitalizations and emergency department (ED) visits, according to research from Rutgers University and the U.S. Agency for Healthcare Research and Quality.

The analysis of state-level inpatient and ED data from 2011 to 2018 showed that such disparities fell 10 percent or more in states that expanded eligibility compared to states that continued with older, stricter requirements.

Benefit expansion didn’t affect the relatively smaller disparities in preventable hospitalizations and ED visits between Hispanics and non-Hispanic white adults. The study didn’t examine disparities between white and Asian adults.

“Preventable hospitalizations and ED visits are important health metrics for assessing access to outpatient care. These include hospitalizations for diabetes or high blood pressure that are preventable with high-quality community level care,” said Sujoy Chakravarty, an associate research professor and health economist at the Rutgers Center for State Health Policy and a lead author of the study, published in Health Affairs. “The decline in disparities indicates that increased coverage through Medicaid expansion was an effective tool for providing valuable care to underserved communities.”

Starting in 2014, the Affordable Care Act allowed states (and encouraged them with subsidies) to expand Medicaid coverage to adults with income up to 138 percent of federal poverty thresholds.

The researchers utilized hospitalization data from 29 states and ED data from 26 states to understand the effects by comparing changes in disparities in states that expanded to states that didn’t expand eligibility.

The study population comprised adults ages 27 to 64. Family coverage mandates from 2010 cover younger people; Medicare covers older ones. The analysis controlled for age, sex and state variables such as median household income, poverty rate and community hospital beds per 1,000 residents.

In the five years after expansion became possible, Black-white disparities in preventable hospitalizations as defined by Agency for Healthcare Research and Quality’s Prevention Quality Indicators – decreased more in expansion states than non-expansion states reflecting a 10.4 percent decrease in disparities associated with the Medicaid expansion.

In contrast, Black-white disparities in preventable ED visits rose in non-expansion states and to a lesser extent in expansion states which was not statistically significant - reflecting a 13.5 percent reduction in disparities associated with the Medicaid expansion.

The effects are significant in the context of the large disparities that existed before 2014. Rates of preventable hospitalizations and ED visits for non-Hispanic Black adults were 2.1 to 2.7 times those of non-Hispanic white adults in 2011–13.

The study’s findings suggest that Medicaid expansion would improve access to care and address health gaps in the 11 states that have opted against Medicaid expansion. States with expanded eligibility will need to test new strategies for service delivery and financing, as many of them currently do.

“The federal government has established statutes for Medicaid programs, but states apply for waivers to innovate care by covering new services or populations,” said Chakravarty, who leads a team of researchers evaluating the effects of several such experiments in New Jersey. “State waivers may allow coverage of upstream services such as housing or transportation, and access to these social determinants of health are critical for ensuring health and equity.”