The ACA allowed states to expand Medicaid coverage for adults, and 25 did so by 2014. Since then, coverage rates have increased more in expansion states than elsewhere.
But the impact of marital status - an important predictor of health care access - on coverage after Medicaid expansion has been unclear.
"Gains in health insurance coverage from Medicaid expansion were greater for married persons, especially married women, compared to unmarried persons," said lead author Jim Stimpson, from Drexel University's Dornsife School of Public Health in Philadelphia.
In this study, published Oct. 23 in the journal PLOS ONE, Stimpson and colleagues analyzed data on nearly 4 million adults who took part in a nationwide survey from 2010 to 2016.
It confirmed previous findings that overall coverage rates were higher in Medicaid expansion states. It also found that uninsured rates after expansion were 1.6 percentage points lower for married women than for those who were unmarried. A similar difference was not seen in men.
Medicaid coverage rates were 2.6 percentage points higher for married women than for unmarried women, and 1.8 percentage points higher for married men than for unmarried men.
Overall, uninsured rates among married people were lower in Medicaid-expansion states than elsewhere. In the past, singles were more likely than marrieds to be uninsured, and the gap appears to have widened.
In other words, "lack of implementation of Medicaid expansion disproportionately impacted unmarried men and women in states that chose not to expand Medicaid," Stimpson noted in a journal news release.
Since 2014, more states have expanded Medicaid coverage for adults, and some are still considering expansion.