(HealthDay)—States that expanded Medicaid cut the probability of non-elderly near-poor adults being uninsured and lowered average out-of-pocket spending, according to a study published online Jan. 24 in Health Affairs.

Fredric Blavin, Ph.D., from the Urban Institute in Washington, D.C., and colleagues used data from 2010 to 2015 to estimate the effects of Medicaid expansion on coverage and out-of-pocket expenses versus the effects of Marketplace coverage.

The researchers found that for adults with family incomes of 100 to 138 percent of poverty, living in a Medicaid expansion state was associated with a 4.5-percentage-point reduction in the probability of being uninsured. It was also associated with a $344 decline in average total out-of-pocket spending, a 4.1-percentage-point decline in high out-of-pocket spending burden (spending more than 10 percent of income), and a 7.7-percentage-point decline in the probability of having any out-of-pocket , compared to living in a non-expansion state.

"These findings suggest that policies that substitute Marketplace for Medicaid eligibility could lower coverage rates and increase out-of-pocket expenses for enrollees," the authors write.