A new study by KFF (formerly Kaiser Family Foundation) laid out prior authorization denials by Medicare Advantage insurers, Medicaid managed care insurers and Affordable Care Act (ACA) Marketplace insurers, as well as how often prior authorization denials were overturned on appeal.
The report — Prior Authorization Metrics Provide New Insights Into Insurer Practices, but Gaps Remain — was published Aug. 13. It analyzed data that insurers working with the Centers for Medicare & Medicaid Services (CMS) are required to report per a February 2024 final rule designed to “improve the electronic exchange of healthcare data and streamline processes related to prior authorization requirements for Medicare Advantage organizations, state Medicaid fee-for-service programs, state Children’s Health Insurance Program (CHIP) FFS programs, Medicaid managed care plans, CHIP managed care entities, and Qualified Health Plan issuers on the Federally Facilitated Exchanges.”
“As part of these requirements, every year, payers in these programs are now required to publicly post on their websites specified prior authorization metrics, including approval and denial rates and response times, aggregated for all medical items and services (excluding prescription drugs) for the previous calendar year,” the KFF study said.
While durable medical equipment prior authorization activity would have been included in the data reported, “the aggregated approval statistics do not allow for further analysis into which services are being denied,” KFF said.
Double-digit denial rates
Once insurers posted their first years of data — for calendar year 2025 — by March 2026, KFF “collected and analyzed these metrics from the largest insurers in most market segments for which reporting is required, including Medicare Advantage, Medicaid managed care, and the Affordable Care Act federally facilitated Marketplace.”
Medicare Advantage denied 12% of standard prior authorization requests. Medicaid managed care insurers had a 14% prior authorization denial rate, and ACA Marketplace insurers denied 18% of prior authorizations.
Among Medicare Advantage insurers, the rates of prior authorization denial varied significantly. Elevance had a 5% rate, for example, while UnitedHealth Group had a 17% denial rate.
After UnitedHealth, Centene had the second-highest incidence of prior authorization denials (15%) among Medicare Advantage plans, followed by 13% denial rate for Kaiser Permanente, 8% for CVS, and 7% for Humana.
Expedited prior authorization requests had slightly lower prior authorization denial rates across insurer types. Medicare Advantage averaged a 10% of denials for expedited requests. Medicaid managed care had a 12% denial rate for expedited requests, which ACA Marketplace insurers had a 16% expedited denial rate.
Among the six Medicare Advantage insurers in the KFF report, Elevance again had the lowest percentage (3%) of expedited request denials, followed by Kaiser Permanente (7%), Humana (10%) UnitedHealth and CVS (11% each). Centene (13%) had the highest rate of expedited request denials.
An underused appeals option
The study added that many denied prior authorizations were approved upon appeal, though that road is not one often taken.
“Insurers overturned a considerable share of denials upon appeal, with variation by market,” KFF said. “Although enrollees or their providers can appeal denied prior authorization requests, research shows that denials are rarely appealed in Medicare Advantage, Medicaid MCOs or the ACA Marketplace. However, the prior authorization data demonstrate that when denials are appealed, a considerable share are overturned.”
Standard prior authorization requestions initially denied by Medicare Advantage insurers had a 67% success rate on appeal. For Medicaid managed care, that rate was 47%, and 43% for ACA Marketplace insurers.
“We do not present appeals data for expedited requests because that metric is optional, and most insurers did not provide this information,” KFF noted.
Among Medicare Advantage insurers, Centene (93%) had the highest rate of denials overturned on appeal, followed by CVS (89%), Elevance (75%), Humana (64%), UnitedHealth Group (60%) and Kaiser Permanente (40%).
On appeal, UnitedHealth Group overturned 81% of Medicaid managed care prior authorization denials.
KFF noted that the overturn rate for Medicare Advantage plans “varied substantially.”
“High overturn rates could raise questions about whether the initial request should have been approved or could indicate that the initial request was missing the required documentation to justify the service,” the organization added. “Either way, the appeals process can be complicated and time-consuming for providers and patients.”
