In 2025, Medicare Advantage insurers denied 12% of standard prior authorization requests, Medicaid managed care insurers denied 14% and ACA Marketplace insurers denied 18%, according to a new analysis from KFF.
The analysis examined 14 insurers across Medicare Advantage, Medicaid managed care and ACA federally facilitated Marketplace plans, representing approximately 71 million enrollees. It comes after a 2024 CMS final rule that requires payers to publicly post prior authorization metrics like approval and denial rates on their websites. However, the data do not show which types of services are most often denied.
KFF found that across all three markets, the median response time was about one day for standard prior authorization requests. For expedited requests, the median response time was about half a day for Medicare Advantage and approximately one day for Medicaid managed care and ACA Marketplace plans. The analysis also explained that denial rates for expedited requests were slightly lower than for standard requests.
Denial rates also vary by insurer. For Medicare Advantage insurers, standard prior authorization denial rates ranged from 5% at Elevance to 17% at UnitedHealth Group. In Medicaid managed care, denial rates ranged from 2% at L.A. Care Health Plan to 23% at Independence Health Group, while ACA Marketplace insurers ranged from 3% at GuideWell to 25% at Centene.
Prior authorization denials are rarely appealed, according to the report. However, when they are appealed, many are overturned. About 67% of prior authorization denials were overturned after an appeal in Medicare Advantage, compared to 47% in Medicaid managed care and 43% in ACA federally facilitated Marketplace.
While the data provides more transparency into prior authorization denials, there are still significant gaps for consumers, according to KFF. For example, insurers are not required to publish the prior authorization data in a standard format, which makes it difficult for people to compare insurers.
“Although a target audience of prior authorization reporting is consumers, those who do not have a deep understanding of health insurance terminology and concepts may struggle to interpret these reports. … Difficulty locating metrics on insurer websites, an absence of more detailed data, and unclear reporting standards could additionally pose challenges for consumers wishing to use the data directly to compare health insurers, as envisioned in the 2024 regulation. However, intermediaries may aggregate and explain the data to make it more accessible for consumers,” KFF said.
Last year, insurers made a series of commitments to streamline prior authorization including improving transparency on determinations and standardizing electronic prior authorization. Providers, however, are still skeptical about these commitments and whether they’ll make meaningful improvements.
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