As of 2025, 40 states and the District of Columbia have implemented expansions of Medicaid eligibility under the Patient Protection and Affordable Care Act (ACA). A large body of research has found these expansions are associated with improved health care coverage, access to care, and health outcomes. The One Big Beautiful Bill Act (OBBBA) recently signed into law introduces significant changes to Medicaid expansion, including a requirement for states to condition enrollment on working or participating in other qualifying activities for at least 80 hours each month. Current estimates from the Congressional Budget Office suggest this work requirement will result in coverage loss for millions of expansion enrollees.
In a study in Health Affairs Scholar, Dr. William Schpero, assistant professor in population health sciences, Dr. Yasin Civelek, research associate in population health sciences, and Manyao Zhang, senior data and research analyst, assessed diagnosed health conditions and health care use of adults enrolled in Medicaid under the ACA expansion. This publication is the first peer-reviewed work that examines health care needs in the expansion population nationally, providing a baseline assessment in advance of the implementation of work requirements and potential coverage losses.
The analysis used federal Medicaid claims data for 2019, one year before the COVID-19 pandemic, as well as 2022, the most recent year available. Researchers found that over one-third of enrollees had at least one diagnosed health condition, one-fourth had an emergency department visit, and about half had multiple outpatient visits and prescription drug refills.
“Most expansion enrollees were actively receiving care,” Dr. Schpero said. “The coverage losses predicted under the OBBBA's work requirement will thus likely introduce discontinuities in care.”
Importantly, the OBBBA includes mandatory work requirement exemptions for certain groups, including people who are "medically frail" or actively in treatment for substance use disorder.
“We see this paper as an early proof-of-concept that states could use claims data to automate the exemption process if ultimately allowed to do so in final regulations,” Dr. Schpero said.
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