Traditional Medicare spent decades running with almost no prior authorization. In January that changed. A six-year federal pilot called WISeR now requires clinicians in Arizona, New Jersey, Ohio, Oklahoma, Texas and Washington to get sign-off before selected services are covered, and the contractors doing the reviewing are mostly technology firms encouraged to use AI.
The first independent look at what happened landed in JAMA this week from researchers at the University of Minnesota and Brown University. Their conclusion is blunt: the requirements had an immediate effect, and nobody yet knows whether the care that disappeared was waste or necessary treatment.
What the numbers show
The team pulled monthly service use from Epic Cosmos, an EHR dataset covering more than 300 million patients, and compared the six pilot states against the rest of the country. The window ran 24 months before launch through the first six months after.
Epidural steroid injections, the highest-volume service in the model, fell about 15%. The remaining targeted services fell nearly 20%. Services slated for the pilot but never activated did not decline, which the authors treat as evidence that prior authorization, not an unrelated trend, moved the numbers.
The effect also faded. Injection reductions narrowed from roughly 21% in the opening quarter to about 9% in the next, while other services slipped from 21% to 18%.
What nobody can answer yet
“The key question we can’t yet answer is whether the care not received was wasteful or necessary,” said Hannah Neprash, the study’s lead author. Co-author Michael Barnett warned that added administrative work may not justify a small change in who ultimately gets treated.
The design tracked utilization, not costs, denials or patient outcomes, and covers six months of a six-year pilot. CMS is weighing whether to extend or broaden the model.
