Dive Brief:

  • According to a new analysis of prior authorization metrics by health policy research organization KFF, insurers denied at least 1 in 8 standard prior authorization requests across Medicare Advantage (MA), Medicaid managed care, and the Affordable Care Act (ACA) marketplaces last year.
  • Insurance juggernaut UnitedHealth had the highest denial rate in MA at 17%. Independence Health Group, which operates Blues plans, had the highest denial rate in Medicaid at 23%, while Centene, a major player in government programs, had the highest rate in the ACA marketplaces at 25%.
  • This is the first public look at insurers' prior authorization denial metrics, following a federal requirement that insurers post such data publicly starting this year.

Dive Insight:

The Centers for Medicare & Medicaid Services (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 prior authorization information since 2019, the new regulation broadened the required data reporting and, for the first time, added reporting requirements for insurers in Medicaid managed care organizations (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 obtain approval before delivering treatment. Physicians widely criticize prior authorization, arguing that it delays care and creates unnecessary administrative burden.

The Trump administration has identified prior authorization as a target for healthcare reform, securing pledges from insurers last summer to reduce their more onerous policies and implement other changes. As of April, major insurers report they have cut 11% of prior authorizations.

KFF's analysis, which examined 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 frequently across all three markets.

Insurers deny between 10% and 18% of requests on average

Share of prior authorization requests denied, by type of request and market segment

Denial rates varied significantly among insurers within 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 Independence Health Group, while ACA marketplace denials ranged from 3% for Guidewell to 25% for Centene.

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

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 noted that 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. Moreover, insurers used inconsistent formats for reporting the metrics, complicating comparisons. 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.