Medicare Advantage insurers denied 4.1 million prior authorization requests in 2024, analysis finds

Medicare Advantage insurers denied 4.1 million prior authorization requests in 2024, and most of the denials that were challenged were overturned, according to a KFF analysis of federal data published January 28, 2026 ^[1][2].

Insurers made nearly 53 million prior authorization determinations that year, up from 49.8 million in 2023 ^[1]. About 7.7 percent of requests were fully or partially denied, a somewhat larger share than the 6.4 percent denied in 2023 and about the same as the 7.4 percent denied in 2022 ^[1].

How often denials were appealed

Only 11.5 percent of denied requests were appealed in 2024, close to the 11.7 percent appealed in 2023 but higher than the 7.5 percent appealed in 2019 ^[1]. Of the appeals filed, 80.7 percent were partially or fully overturned, and more than eight in ten appeals have overturned initial denials in every year the analysis covers ^[1].

KFF described those overturned requests as care that a health care provider ordered and that was ultimately deemed necessary, but that may have been delayed while the denial was appealed. It noted such delays may have negative effects on a patient's health ^[1].

The analysis covers 2019 through 2024 and uses data that insurers submit to the Centers for Medicare & Medicaid Services, or CMS. It does not include requests or denials broken down by type of service or type of plan, because CMS does not collect or report that information ^[1].

For comparison, traditional Medicare had just over 625,000 prior authorization requests in fiscal year 2024, or about two requests per 100 beneficiaries. A larger share of those requests was denied: 22.9 percent, or less than 150,000 ^[1].

Denial rates varied widely by insurer, according to a separate summary of the KFF findings from the American Society for Gastrointestinal Endoscopy ^[2]. Elevance Health had 3.0 prior authorization requests per enrollee and a denial rate of 4.2 percent, while UnitedHealth Group had 1.0 request per enrollee and the highest denial rate at 12.8 percent. Centene had 2.9 requests per enrollee and a 12.3 percent denial rate ^[2].

Why it matters for patients

Nearly all Medicare Advantage enrollees — 99 percent — need prior authorization for at least some services, most commonly higher-cost care such as inpatient hospital stays, skilled nursing facility stays and chemotherapy ^[1]. That is a much broader set of services than traditional Medicare requires ^[1].

For people in Medicare Advantage, the numbers suggest that a denial is often not the final answer if it is challenged, but that relatively few denials get challenged ^[1].

What the report does not show is how prior authorization works for any particular medication or treatment. Because the data are aggregated to the contract level, denial rates for specific drugs — including GLP-1 medications such as semaglutide (Ozempic, Wegovy, Rybelsus) and tirzepatide (Mounjaro, Zepbound) — have not been disclosed in this analysis ^[1]. CMS has said it is running a pilot to collect more detailed data at the plan and service level, which CMS anticipates expanding to all plans in 2027 ^[1].

KFF polling cited in the analysis found that about two-thirds of Medicare beneficiaries consider delays and denials of care by insurers to be a major problem ^[1].

What happens next

In June 2025, several large insurers pledged to improve prior authorization, including by reducing the volume of medical services subject to the process by January 1, 2026 ^[2].

On January 1, 2026, the administration launched the Wasteful and Inappropriate Spending Reduction, or WISeR, model, which tests enhanced technology for prior authorization for an additional set of services in traditional Medicare in six states ^[1].

Bipartisan legislation in the House and Senate, the Improving Seniors' Timely Access to Care Act (H.R. 3514 and S. 1816), would codify and expand recent prior authorization rule changes for Medicare Advantage plans. The American Society for Gastrointestinal Endoscopy states that it endorses the bill ^[2].

The outcome of that legislation has not been reported.