Medicare Put an AI Reviewer in Front of Doctors First, and Some Care Dropped 20%

The first solid data on Medicare’s new prior-authorization rule have arrived. The biggest question remains unanswered.

For a long time, Original Medicare almost never required a doctor to get permission before ordering treatment. If your doctor said you needed a procedure, you generally received it. That has always been one of its biggest advantages.

In a handful of states, that changed this year. Now the first hard evidence is showing what happened afterward.

Beginning in January, Medicare started requiring advance approval for a limited set of procedures in Arizona, New Jersey, Ohio, Oklahoma, Texas and Washington. Outside contractors manage the reviews. Most are technology firms, and Medicare has encouraged them to use artificial intelligence.

Almost immediately, Original Medicare patients in those states began receiving noticeably less of that care. What no one can yet say is whether the care they lost was actually needed.

Here’s what the research found, why it still matters if you live elsewhere, and what to do if one of your planned procedures is included.

What changed once doctors had to ask first

Researchers from the University of Minnesota and Brown University recently published the first study of the program, called WISeR, in JAMA. Using Epic Cosmos, a database with more than 300 million patient records, they compared the six states with the rest of the country.

According to the University of Minnesota’s summary of the study, the findings were:

• Epidural steroid injections for back pain, the most common service on the list, fell 15% compared with trends in the rest of the country.
• The other services on the list declined by about 20%.
• Procedures Medicare had originally planned to include but ultimately left out showed no meaningful decline.

That last point is the key. If some outside force had caused the drop, those procedures likely would have fallen too. They did not, which suggests the approval requirement itself was responsible.

The effect was strongest at the start. For back injections, the gap was about 21% in the first quarter, then narrowed to around 9% in the next three months. For the rest of the list, it changed only slightly: 21%, then 18%.

Was the missing care wasteful? No one can say yet

Medicare says the program is aimed at services that are vulnerable to fraud and waste. Some of the care that disappeared may well fit that description.

But the researchers are clear about the limits of their work. Lead author Hannah Neprash, an associate professor at the University of Minnesota School of Public Health, said they still cannot determine “whether the care not received was wasteful or necessary.”

That is the uneasy part. When something becomes harder to get, fewer people get it. That does not prove it was unnecessary. It only proves the barrier is effective.

The agency itself has also acknowledged that most doctors are not the issue. Abe Sutton, director of the Center for Medicare and Medicaid Innovation, said in a statement to KFF Health News that “the percentage of providers committing waste, fraud, and abuse is small.”

Patients, meanwhile, are paying in delays and inconvenience. KFF Health News reported on a 65-year-old Oklahoma cattle rancher who had been receiving a back injection every three months for years. After he was suddenly told he needed approval, he spent 10 hours driving to get one.

The same report cited data from Sen. Maria Cantwell’s office showing that nearly 100 patients in the University of Washington health system alone were left waiting for back injections earlier this year because of delays tied to the program.

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Why this matters even if you live elsewhere

WISeR is scheduled to run through 2031, and Medicare can add more services to the list over time. Neprash says the agency is now considering whether to keep the program in place or expand it.

In a statement to KFF Health News, Sutton said no changes to the list were being considered at that time, though the agency continues to review whether changes are warranted.

For now, Medicare’s guide for doctors says the list includes procedures such as:

• Epidural steroid injections for pain
• Knee arthroscopy for arthritis
• Kyphoplasty and similar procedures for spinal compression fractures
• One type of neck fusion surgery
• Implanted nerve stimulators for chronic pain, sleep apnea, seizures and bladder control
• Skin substitutes for chronic leg and foot wounds, except in Arizona and Washington

There is also an important twist, especially during open enrollment. If these extra steps make you think about switching to Medicare Advantage, pause first.

WISeR does not apply to Medicare Advantage plans. They already use prior authorization, and they use it far more often.

According to KFF, 99% of Advantage enrollees are in plans that require approval for some services. Medicare Advantage insurers handled nearly 53 million approval requests in 2024. Original Medicare handled just over 625,000 in fiscal 2024.

Before changing plans, read about which private Medicare plans denied specialized care at the highest rates.

And if you leave Original Medicare, getting back in with solid supplemental coverage is not guaranteed. Read “Leaving Medicare Advantage This Fall? Medigap Can Turn You Down” before making any switch.

If you live in one of the six states, here’s what to do

The approval request is your doctor’s responsibility, not yours. Still, you are the one who has to deal with the outcome, so keep track of it.

• Ask before you schedule. If your procedure is on the list, ask whether the approval request has been submitted. The contractor usually responds within three calendar days, or within two if a delay could seriously endanger your health.
• Watch your mail. You should receive a copy of every decision. An approval lasts 120 days, so make sure the procedure gets scheduled.
• Do not accept the first “no.” A denied request cannot be appealed by itself. But your doctor can resubmit it as often as needed with additional records, and can request a discussion with one of the contractor’s clinicians. Push the office to follow through.
• Read before you sign. If your doctor proceeds after a denial, you should expect an Advance Beneficiary Notice, which says you may have to pay if Medicare does not. Once Medicare formally denies the claim, your usual appeal rights apply.

That final point matters more than many people realize. In Medicare Advantage, only 11.5% of denied approval requests were appealed in 2024, and 80.7% of those appeals were fully or partly reversed, KFF found. Different program, same lesson: many denials do not survive when someone pushes back.

If you are wondering why the companies performing these reviews may lean toward denial, we explained how they are paid in “Medicare Is Letting AI Say No — and the Companies Doing It Get Paid for Denials.”

The takeaway

If you are on Original Medicare, its main advantage is still mostly intact. Outside of six states, your doctor usually does not need permission first.

But this study shows how quickly that changes once permission is required. Some care fell by roughly 20% compared with other states, and the researchers still cannot say whether anyone was better off because of it.

Watch what Medicare does with WISeR next. And whatever you decide before open enrollment ends, do not let frustration with red tape push you into a plan that has even more of it.