Insurers denied between 12% to 18% of prior authorization requests in 2025: KFF

According to a new analysis from the Kaiser Family Foundation (KFF), insurers denied between 12% to 18% of standard prior authorization requests across different market segments in 2025. The study examined Medicare Advantage, Medicaid managed care, and Affordable Care Act (ACA) federally facilitated Marketplace (FFM) websites from insurers with at least 2.5% market share in their respective segments. The research was based on data collected from 14 unique insurers, representing approximately 71 million enrollees.

In Medicare Advantage, 12% of standard prior authorization requests and 10% of expedited requests were denied on average. Medicaid managed care saw a 14% denial rate for standard requests and 12% for expedited requests. ACA FMs had the highest denial rates, with 18% of standard requests and 16% of expedited requests denied. Among the six analyzed Medicare Advantage insurers, UnitedHealth Group denied the most standard prior authorization requests (17%) and Centene had the highest rate of expedited requests (13%).

For Medicaid managed care, Independence Health Group denied the most standard requests (23%) and CareSource had the highest rate of expedited requests (21%). The largest denial rates were seen in ACA Marketplace insurers, with Centene denying the most standard (25%) and expedited (23%) requests.

Although most prior authorization denials are rarely appealed, 67% of denials were overturned in Medicare Advantage, 47% in Medicaid managed care, and 43% in ACA FMs. The median time between submitting a prior authorization request and the insurer's response, or determination, was about 1 day for standard requests across all segments. Expedited requests had a median response time of about half a day in Medicare Advantage, under 1 day in Medicaid managed care, and 1 day in ACA Marketplaces.

The report highlights that despite regulatory efforts to enhance transparency, difficulties in accessing and interpreting metrics on insurer websites, and gaps in data reporting, limit the public's ability to make informed decisions. Researchers found a gap in standardizing templates and metrics required for reporting, which affects the usability of the data for consumers.

A separate March 2025 report revealed that a quarter of insured adults struggle to understand insurance terms. The current reporting requirements only mandate percentages of prior authorization requests for each metric, but researchers argue that including numeric counts could provide more context on whether denial rates represent a "meaningful volume" of requests.