Adults in the income range for the Affordable Care Act's Medicaid expansion are healthier than pre-ACA enrollees.

The Affordable Care Act (ACA) has dramatically increased the number of low-income nonelderly adults eligible for Medicaid. Starting in 2014, states can elect to cover individuals and families with modified adjusted gross incomes below a threshold of 133 percent of federal poverty guidelines, with a 5 percent income disregard. We used simulation methods and data from the Medical Expenditure Panel Survey to compare nondisabled adults enrolled in Medicaid prior to the ACA with two other groups: adults who were eligible for Medicaid but not enrolled in it, and adults who were in the income range for the ACA's Medicaid expansion and thus newly eligible for coverage. Although differences in health across the groups were not large, both the newly eligible and those eligible before the ACA but not enrolled were healthier on several measures than pre-ACA enrollees. Twenty-five states have opted not to use the ACA to expand Medicaid eligibility. If these states reverse their decisions, their Medicaid programs might not enroll a population that is sicker than their pre-ACA enrollees. By expanding Medicaid eligibility, states could provide coverage to millions of healthier adults as well as to millions who have chronic conditions and who need care.