Study finds prior-authorization rules inconsistent

Stanford University researchers published a study on May 18 finding that prior-authorization rules at Aetna, Humana and UnitedHealthcare showed little consistency across major commercial insurers. The report, published in *Annals of Internal Medicine*, reviewed publicly available provider manuals and compared when prior authorization was required and what documentation clinicians had to submit. (medicalxpress.com) Medscape reported on May 21 that physicians said the variation affects both clinical approvals and day-to-day office workflow. (ajmc.com) The study adds new detail to a long-running complaint from doctors that prior authorization is not a single process but a patchwork of insurer-specific rules. (medicalxpress.com) The American Medical Association said on May 13 that physicians remain skeptical that insurer reform pledges will produce meaningful change, even as insurers face deadlines stretching from 2025 through 2027. ### Which insurers did the study compare? The study examined Aetna, Humana and UnitedHealthcare, using their public provider manuals to identify prior-authorization requirements tied to HCPCS service codes. Researchers grouped those codes into medical and surgical services, medications, behavioral health and other categories, then built a searchable database to compare the rules. (medicalxpress.com) MedicalXpress, citing the Annals report, said the work was part of a Stanford-led research program on whether health-care contract rules could be standardized in a way similar to ICD-10 coding. The researchers used automated review with manual checks to compare insurer rules at scale. (ama-assn.org) ### How different were the rules in practice? AJMC reported that among 4,645 HCPCS codes requiring prior authorization by at least one insurer, only 14% overlapped across all three insurers and 66% were unique to a single insurer. That means most services flagged for authorization by one insurer were not flagged the same way by the others. (ajmc.com) The criteria used to trigger prior authorization also diverged. AJMC said Aetna relied on fewer decision and approval criteria than UnitedHealthcare for medical and surgical services, while site-of-service review requirements applied to more than 200 services at Aetna, compared with 11 at Humana and 33 at UnitedHealthcare. An Epocrates item summarizing the study said UnitedHealthcare used five criteria for medical and surgical services, including state, age, diagnosis, equipment cost and site of care. (medicalxpress.com) ### Why are physicians saying speed alone will not fix this? Medscape reported on May 21 that some physicians questioned whether reforms focused mainly on faster approvals would reduce inappropriate denials. (ajmc.com) Their concern, as described in the report, was that a quicker process does not by itself address whether the underlying rules are clinically appropriate or consistently applied. The AMA made a similar point in a May 13 press release. The group said only 33% of surveyed physicians believed the latest insurer pledge would make a meaningful difference, and only 24% said medical-necessity denials were consistently reviewed by an appropriately qualified clinician. (ajmc.com) AMA President Bobby Mukkamala said physician trust in voluntary insurer pledges is “deeply eroded” after years of unfulfilled commitments. ### How much time does prior authorization consume? The American Medical Association said physicians report a consistently high administrative burden from prior authorization across major health insurers. A separate summary of current rules and transparency changes said the average physician handles about 39 prior-authorization requests a week, consuming roughly 13 hours of staff time. (medscape.com) Medscape’s May 21 report said burdens vary by insurer and consume hours each week. MedicalXpress said the authors concluded that a shared, searchable database of insurer rules is feasible and could improve transparency for clinicians and patients. The next reference point for the study is the Annals publication itself: “Variation in Commercial Insurer Prior Authorization Rules,” published online in May 2026 with DOI 10.7326/ANNALS-25-05289. (ama-assn.org) (medicalxpress.com)