The first study of Medicare’s WISeR prior authorization model found a fast drop in care. A research letter in JAMA, published October 26, 2026, reports that epidural steroid injections fell 15% in the six pilot states compared with trends elsewhere. Other targeted services fell about 20%. The drop shrank after the first quarter.
What is the WISeR model?
WISeR is a CMS pilot that adds prior authorization to traditional Medicare in six states. The full name is the Wasteful and Inappropriate Service Reduction Model. It runs for six years, from January 1, 2026 through December 31, 2031.
Traditional Medicare has used very little prior authorization in the past. WISeR changes that for a set of services that CMS sees as open to fraud, waste and abuse. The JAMA letter counts 41 services in the model. CMS pays outside companies, called model participants, to review the requests. CMS encourages them to use artificial intelligence in that review. A human clinician must still review every request the company does not approve.
Each state has one participant:
- Arizona: Zyter Inc. (Noridian, JF)
- New Jersey: Genzeon Corporation (Novitas, JL)
- Ohio: Innovaccer Inc. (CGS, J15)
- Oklahoma: Humata Health, Inc. (Novitas, JH)
- Texas: Cohere Health, Inc. (Novitas, JH)
- Washington: Virtix Health LLC (Noridian, JF)
WISeR applies to Original Medicare only. Medicare Advantage plans run their own prior authorization rules.
What did the JAMA study measure?
The study tracked how often Medicare patients got WISeR services before and after the launch. Hannah Neprash of the University of Minnesota and Michael Barnett of Brown University led the work.
They used Epic Cosmos, a large set of health records. It covers more than 300 million patient records. They compared monthly use in the six pilot states with use in all other states and Washington, DC. The study looked at two years before launch and six months after.
The authors also checked services that CMS planned to add but never did. Those showed no clear drop. So prior authorization looks like the cause.
How much did care drop under WISeR?
Epidural steroid injections for back pain fell 15% compared with other states. These shots are the most used service in the model. Other targeted services fell about 20%.
The effect was largest right after launch. For the shots, the drop was about 21% in the first quarter of 2026 and about 9% in the second. For the other services, it went from 21% to 18%.
The authors cannot yet tell if the missed care was needed. “The key question we can’t yet answer is whether the care not received was wasteful or necessary,” Neprash said in the University of Minnesota release.
Why did the drop shrink after the first quarter?
The study suggests practices learned the new process. “The early results suggest that doctors may be adapting rapidly to the new system,” Barnett said.
That fits what most offices see with any new payer rule. The first weeks bring missing notes, unclear forms and slow replies. Once staff learn what reviewers want, more requests pass on the first try. The smaller drop in the second quarter hints that many offices have caught up.
Which services need prior authorization under WISeR?
The CMS provider fact sheet lists these service groups for 2026:
- Electrical nerve stimulators
- Sacral nerve stimulation for urinary incontinence
- Phrenic nerve and vagus nerve stimulation
- Induced lesions of nerve tracts
- Epidural steroid injections for pain management
- Percutaneous vertebral augmentation for compression fracture
- Cervical fusion
- Arthroscopic lavage and debridement for the osteoarthritic knee
- Hypoglossal nerve stimulation for obstructive sleep apnea
- Incontinence control devices
- Diagnosis and treatment of impotence
- Percutaneous image guided lumbar decompression for spinal stenosis
- Skin and tissue substitutes, only in certain MAC areas with an active LCD
The exact codes sit in Appendix A of the CMS WISeR guide for providers. CMS says the list can change, so check it each quarter.
What happens if a practice skips prior authorization?
The claim gets a medical review before Medicare pays it. CMS gives you two paths. You can send a request first. Or you can do the service and let the claim go through review before payment.
If you skip the request, the MAC flags the claim and the reviewer checks your notes. The MAC then pays or denies. If the reviewer already said no to your request, the MAC denies the claim.
A request that is not approved does not stop you from treating the patient. You must give the patient an Advance Beneficiary Notice (ABN) first. Normal Medicare appeal rights still apply to any denied claim.
How fast do WISeR reviewers decide?
CMS says participants typically decide within three days of a request. For urgent cases, where delay could seriously harm the patient, the decision is due within two days.
You can resubmit a request as many times as you need. You can also ask for a peer to peer talk with the reviewer as part of a resubmission. Each claim that went through prior authorization should carry its Unique Tracking Number (UTN).
What this means for practices with 1 to 15 providers
Pain, spine, bone and joint, urology, ENT, sleep and wound care offices in the six states feel this most. Small groups often have one person on authorizations. A clear process protects cash flow and patient care. Here is where to start.
- Map your risk. Pull last year’s Original Medicare claims and flag every code on the WISeR list. Note the count and dollars for each one.
- Pick a path for each service. A request gets you an answer before the visit. Review after the fact moves the risk to after you give care. Most small offices are safer asking first.
- Build a checklist for each service. Use the LCD or NCD named in the fact sheet. List the exact notes, scans and prior treatment the policy asks for.
- Track the UTN. Add a field in your billing workflow so every WISeR claim carries its tracking number.
- Resend and talk. Fix the missing note and send it again, or ask to speak with the reviewer.
- Give ABNs when needed. If a request is not approved and the patient still wants care, have the ABN signed before the visit.
- Work toward exemption. CMS started an exemption program in July 2026. You need at least 10 requests. Each reviewer sets an approval bar no higher than 90%. Exempt providers keep that status for at least one full year.
- Watch facility claims. In ASCs and hospital outpatient departments, review applies to the facility claim. If the MAC denies that claim, it can flag your linked claim too.
Practices outside the six states should still pay attention. WISeR runs through 2031, and CMS will judge it on results like these.
Frequently asked questions
Which states are in the WISeR model?
Arizona, New Jersey, Ohio, Oklahoma, Texas and Washington. The model applies to Original Medicare patients in those states.
Does WISeR apply to Medicare Advantage?
No. WISeR covers Original Medicare only. Medicare Advantage plans set their own prior authorization rules.
Can AI deny a WISeR request on its own?
No. CMS requires a human clinician with relevant expertise to review every request that is not approved.
How long does a WISeR decision take?
CMS says participants typically decide within three days. Expedited requests are due within two days when delay could seriously harm the patient.
What if I perform a WISeR service without approval?
The claim goes to prepayment medical review. If the participant already turned down your request, the MAC denies the claim, and normal appeal rights apply.
Can my practice become exempt from WISeR review?
Yes. The exemption program began in July 2026. Providers need at least 10 requests and an approval rate at or above the threshold their participant sets, which can be no higher than 90%.
Where should my practice start?
Start by finding which of your claims now face review and where your notes fall short. WeBill Health works as a revenue defense partner for independent practices. We use internal payer rule libraries built by specialty and carrier, with more than 500 payer rulesets covered by internal libraries, and coding experts review every claim before it goes out. Request a Revenue Health Audit and we will show you where prior authorization gaps may be costing you visits and payments.
Sources
- Neprash HT, Barnett ML. Changes in Service Use Following the Introduction of AI Enabled Prior Authorization in Medicare. JAMA. Published online October 26, 2026.
- University of Minnesota School of Public Health news release, October 26, 2026: Medicare’s prior authorization pilot test led to an immediate drop in use of services, study finds
- CMS: WISeR (Wasteful and Inappropriate Service Reduction) Model
- CMS: WISeR Model Participants and Impacted Providers Fact Sheet
- CMS: WISeR Model Frequently Asked Questions
- CMS: WISeR Exemption Status Program Fact Sheet
- CMS: WISeR Model Provider and Supplier Operational Guide
