Expanding Medicaid-benefit eligibility to cover all people with income up to 138% of the federal poverty line reduced Black-white disparities in preventable hospitalizations and emergency department visits, a new study finds.

The analysis of state-level inpatient and emergency department (ED) data from 2011 to 2018 showed that such disparities fell 10% 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,” says Sujoy Chakravarty, an associate research professor and health economist at the Rutgers University Center for State Health Policy and a lead author of the study 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% of federal poverty thresholds.

The researchers used 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% decrease in disparities associated with the Medicaid expansion.

Read the full article about Medicaid expansion and racial disparities by Andrew Smith at Futurity.