Dive Brief:

• Insurers denied at least 1 in 8 standard prior authorization requests across Medicare Advantage, Medicaid managed care and the Affordable Care Act marketplaces last year, according to a new analysis of prior authorization metrics by health policy research organization KFF.
• Insurance juggernaut UnitedHealth had the highest denial rate in MA at 17%. Independence Health Group, which operates Blues plans, had the highest denial rates in Medicaid at 23%; while Centene, a major player in government programs, had the highest rates in the ACA marketplaces at 25%.
• It’s the first peek behind the curtain at insurers’ prior authorization denial metrics, after the federal government began requiring insurers to post publicly available data this year.

Dive Insight:

The CMS issued a final rule in 2024 aimed at streamlining prior authorization processes for insurers.

Although insurers in MA have been required to report some information about prior authorizations since 2019, the new regulation broadened the required data reporting and added reporting requirements for the first time for insurers in Medicaid MCOs and the ACA marketplaces.

Heightened public disclosures come as lawmakers and the federal government increasingly scrutinize prior authorization policies, cost-controlling mechanisms wherein insurers require providers to get approval before providing treatment. Doctors loathe prior authorizations, arguing that they delay treatment and create needless paperwork.

The Trump administration has zeroed in on prior authorization as an area of healthcare reform, securing pledges from insurers last summer to pare back their more onerous policies, along with other changes. As of April, major insurers say they’ve cut 11% of prior authorizations.

KFF’s analysis, which dug into 2025 data from 14 insurers with the largest enrollment in each market, found that average standard prior authorization denial rates were 12% in Medicare Advantage, 14% in Medicaid MCOs and 18% in the ACA marketplaces. Expedited requests were denied slightly less often across all three markets.

Denial rates varied significantly among insurers across each market. In MA, denials ranged from 5% for Elevance to 17% for UnitedHealth. In Medicaid, denials ranged from 2% for L.A. Care Plan to 23% for Independent Health Group, while ACA marketplace denials ranged from 3% for Guidewell to 25% for Centene.

High denial rates are concerning given many denied items and services are approved upon appeal — but very few people actually appeal initial denials, according to past research.

The KFF found that two-thirds of claims appeals were successful in MA. Half of denials were overturned on appeal in Medicaid, and 43% of claims were eventually approved in the ACA exchanges.

Still, KFF said the public data had several gaps. Insurers are only required to report percentages, not the total number of prior authorization requests for each metric, making it difficult to fully understand the actual volume of denials, for example.

What’s more, insurers used inconsistent formats for reporting the metrics, making it difficult to compare them. Additionally, insurers are not required to break down the data by service type, making it impossible to see which types of care are denied most frequently.