When people on Medicaid look for a doctor, the search often starts with a long list of names that makes health care seem within reach.
But for many patients, that list often turns into a string of dead ends. Phone calls go unanswered. Offices say they aren’t taking new Medicaid patients. Or the earliest appointment is months away. Eventually, people give up.
A new national study led by Oregon Health & Science University researchers helps explain why.
Advertisement – Continue Reading Below
The study, published this month in the journal Health Affairs, found that nearly a third of roughly 400,000 physicians enrolled in the safety net program did not see a single Medicaid patient in a given year.
Researchers call them “ghost” providers — doctors who appear on paper but don’t show up in patients’ real experience of getting care, a gap driven by how Medicaid measures participation and how provider networks work.
“It’s not just administrative friction, it’s a psychological issue and an access issue,” said Dr. Jane Zhu, the study’s senior author and an associate professor of medicine at OHSU. “From a patient perspective, this is adding real burdens.”
In many cases, doctors stay enrolled because their hospital or clinic requires it, even when their practices are full of patients with private insurance, according to the study’s authors. Others enroll early in their careers and later stop accepting Medicaid patients without formally unenrolling, the researchers said.
The authors said the gap between being listed as a Medicaid provider and actually seeing patients has “critical implications for access,” because low participation can make it harder for patients to get timely care.
Medicaid is the nation’s largest public insurance program, covering more than 75 million people, including low-income families, children and people with disabilities. States and Medicaid health plans often rely on provider enrollment data to judge whether patients have adequate access to care.
But Zhu said those access measures can be misleading. Provider directories often reflect which doctors are authorized to take Medicaid, not which ones are actually seeing patients, she said — making networks appear larger than they are.
“Enrollment files just tell you if they’re eligible to participate … but it doesn’t say anything about whether their panels are closed, if there are staffing shortages or if they have availability to see patients,” she said.
To examine that disconnect, researchers analyzed federal Medicaid enrollment records alongside billing claims from 2019 through 2021. They focused on five specialties commonly used by Medicaid patients: primary care, psychiatry, cardiology, dermatology and ophthalmology.
Across those specialties, the authors found that “Medicaid enrollment did not consistently translate into active participation.”
Researchers found that about 28% of enrolled physicians did not treat any Medicaid patients in those areas, while another 10% saw fewer than 10 patients.
Meanwhile, a third of the overall group of Medicaid-enrolled physicians in the study treated more than 150 Medicaid patients, meaning much of the care was handled by a small share of providers.
Zhu said that when a small group of physicians carries most of the load, a clinic closure or a doctor leaving can quickly leave patients scrambling to find a new provider.
The problem was especially stark in mental health care.
Researchers found that over 40% of psychiatrists enrolled in Medicaid did not see a single Medicaid patient in the year studied. Even psychiatrists who did participate in Medicaid saw very few patients. The typical psychiatrist treated just three Medicaid patients in a year.
That’s troubling, Zhu said, because Medicaid covers a disproportionate share of people with serious mental illness. KFF, a health policy research organization, estimates that nearly 40% of nonelderly adults on Medicaid have a mental health or substance use condition. Federal data shows that about half of Medicaid enrollees with mental health needs say they aren’t getting the care they need.
The authors wrote that low Medicaid participation among psychiatrists likely reflects a mix of “low reimbursement rates, administrative burdens associated with Medicaid billing, high provider turnover, and factors related to the social and medical complexities of Medicaid enrollees.”
The researchers said doctors aren’t trying to mislead patients. The problem, they said, is a system that counts who is signed up for Medicaid, not who is actually available to provide care.
The study used a national Medicaid claims database and excluded Oregon, South Dakota and Arkansas because of reporting inconsistencies in the states’ federal data, Zhu said. But a 2022 Oregon-specific study by her team found similar patterns, especially in mental health care, suggesting the problem is not unique to the state.
Ultimately, Zhu said, states and federal officials need to rethink how they measure access to care — relying less on provider lists and more on data that reflect whether patients are actually getting care.
She said a clearer picture of real-world access could help public dollars be spent in ways that meaningfully help Medicaid patients get the care they’ve been promised.
© 2026 Advance Local Media LLC
Distributed by Tribune Content Agency, LLC
