Medicare’s prior-authorization pilot led to an immediate drop in use of services, study finds

In January 2026, the federal government launched a pilot program in traditional Medicare requiring advance approval for certain medical treatments and encouraging the use of artificial intelligence to review requests.

The pilot marked a major change for traditional Medicare, where doctors had rarely needed approval before providing treatments. Known as the Wasteful and Inappropriate Service Reduction Model, or WISeR, the pilot launched in six states with the goal of reducing unnecessary treatments and Medicare spending by targeting 41 types of medical services considered vulnerable to fraud, waste and abuse.

For many health policy experts, the introduction of prior authorization into traditional Medicare raised concerns about whether patients would face new barriers to care. Researchers from the Brown University School of Public Health and the University of Minnesota School of Public Health set out to answer some of those questions, examining whether the new requirements changed the care patients received by comparing treatment trends in the pilot states with those in states where the rules did not apply.

In a research letter published in JAMA, the team reported that use of medical services targeted by the program fell significantly in the six pilot states during its first six months. The decline was evident across both the program's most frequently used treatment, epidural steroid injections for back pain, and the other targeted services studied in the analysis.

“The early results suggest that doctors may be adapting rapidly to the new system,” said study co-author Dr. Michael Barnett, a professor at the Brown University School of Public Health and a physician. “We need to watch closely to see if the additional work of prior authorization justifies what might be relatively little change in who gets care.”

To measure the program's early effects, researchers analyzed electronic health records from Epic Cosmos, comparing how often patients received targeted treatments in the six pilot states — Arizona, New Jersey, Ohio, Oklahoma, Texas and Washington — to elsewhere in the country during 2024 and 2025 and the first six months of 2026.

Patients in the pilot states received epidural steroid injections 15% less often than expected based on trends elsewhere in the country. Use of the other targeted services, measured together, was nearly 20% lower.

The declines were greatest during the first three months after the program began. Treatment use remained lower in the following three months, although the differences between pilot states and the rest of the country became smaller.

“The key question we can’t yet answer is whether the care not received was wasteful or necessary,” said lead author Hannah Neprash, an associate professor at the University of Minnesota School of Public Health.

The researchers said further study is needed to determine whether the declines persist and how the program affects patients, clinicians' workloads and Medicare spending over its six-year run.