How often does your insurer deny claims — and how often do patients win on appeal?
Under CMS-0057-F, Medicare Advantage plans, Medicaid and CHIP programs and their managed care plans, and qualified health plans sold on the federally facilitated exchanges (HealthCare.gov) are now required to publicly post their prior-authorization metrics — approval rates, denial rates, and how often denials get overturned on appeal. Those requirements took effect January 1, 2026, with the first set of metrics due by March 31, 2026. Plans sold on fully state-run exchanges may fall outside the rule — check with your state exchange.
This explorer consolidates the public data that exists today — from KFF, HHS OIG, CMS reports, peer-reviewed studies, and court filings — so you can look up your insurer before you need to appeal.
All Medicare Advantage (industry average)
Medicare Advantage · 2024 data
Prior-auth denial rate
7.7% of all prior-auth determinations
Claim denial rate
Not published in cited aggregate sources
Appeal overturn rate
80.7% of appealed prior-auth denials
Medicare Advantage insurers fully or partially denied 4.1 million prior-auth requests in 2024, and only 11.5% of those denials were appealed. In a separate review of denials issued in one week of 2019, HHS OIG found 13% of the denied requests it sampled met Medicare coverage rules and likely would have been approved under Original Medicare.
UnitedHealthcare (UnitedHealth Group)
Medicare Advantage · 2024 data
Prior-auth denial rate
12.8% (highest among large MA insurers)
Claim denial rate
Not published separately
Appeal overturn rate
Not published separately
Asked for prior authorization less often than the MA average — 1.0 requests per enrollee against 1.7 overall. Only Kaiser Permanente asked less (0.6 per enrollee). Separately, the company is a defendant in Estate of Lokken v. UnitedHealth Group, which alleges the use of an algorithm to deny post-acute care. Those allegations have not been resolved.
Humana
Medicare Advantage · 2024 data
Prior-auth denial rate
5.8% (below the 7.7% MA average)
Claim denial rate
Not published separately
Appeal overturn rate
Not published separately
Higher request volume than the MA average — 2.2 prior-auth requests per enrollee against 1.7 overall — but Elevance and Centene plans requested more (3.0 and 2.9 per enrollee).
Aetna (CVS Health)
Medicare Advantage · 2024 data
Prior-auth denial rate
11.9%
Claim denial rate
Not published separately
Appeal overturn rate
Not published separately
Denials were appealed more often here than at any other large MA insurer — 19.9% of denials, against 11.5% across Medicare Advantage overall. No other large insurer reached 12%.
Elevance Health (Anthem plans)
Medicare Advantage · 2024 data
Prior-auth denial rate
4.2% (lowest among large MA insurers)
Claim denial rate
Not published separately
Appeal overturn rate
Not published separately
Requested prior authorization more often than any other large MA insurer (3.0 requests per enrollee) but denied the smallest share of those requests.
Cigna Healthcare
Medicare Advantage · 2024 data
Prior-auth denial rate
Not broken out in the cited source
Claim denial rate
Not published separately
Appeal overturn rate
Not published separately
Not reported individually — insurers with fewer than 1 million MA enrollees are grouped together by KFF. Separately, ProPublica reported in 2023 on a Cigna claim-review system known as PXDX; that system reviews claims after treatment, not prior authorization. Cigna disputed the characterization.
Kaiser Permanente (Kaiser Foundation Health Plan)
Medicare Advantage · 2024 data
Prior-auth denial rate
10.9%
Claim denial rate
Not published separately
Appeal overturn rate
Not published separately
Lowest request volume of any large MA insurer (0.6 requests per enrollee), and denials were appealed least often here (1.6%). Kaiser is structurally atypical — it generally operates its own hospitals and contracts with an affiliated medical group.
Methodology. Numbers are drawn from publicly published KFF analyses, HHS OIG audits, CMS reports, peer-reviewed studies, and court filings. Where an insurer has not published a specific metric we mark it “Not published.” We do not estimate unpublished figures.
What changes March 31, 2026. The CMS Interoperability & Prior Authorization Final Rule (CMS-0057-F) requires Medicare Advantage plans, state Medicaid and CHIP fee-for-service programs, Medicaid and CHIP managed care plans, and qualified health plans sold on the federally facilitated exchanges (HealthCare.gov) to publicly post prior-authorization metrics annually. Plans sold on fully state-run exchanges may fall outside the rule — check with your state exchange. Commercial and ERISA self-funded plans are not covered.
Limits. Aggregate denial rates do not tell you whether your specific claim will be denied. Policy terms, medical necessity, documentation, and state-level protections all matter. This page is informational — not medical, legal, or coverage advice.
Context
Why this matters
Almost nobody appeals. Public data consistently shows that appeals are underused, even though many denials are reversed when patients challenge them. In the ACA marketplace, fewer than 1% of denied in-network claims are formally appealed.
The new data is a lever, not an answer. Knowing your insurer denies 20% of claims doesn’t mean yours was wrongly denied. It does mean you should check whether the denial turns on missing paperwork, prior authorization, coding, coverage rules, or clinical criteria before giving up.
Commercial/employer plans are not covered. If you’re on an ERISA self-funded plan through your employer, your insurer is not required to publish these metrics. Your appeal rights under 29 CFR § 2560.503-1 are still intact — we factor those into every appeal regardless.
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Figures are drawn from publicly available KFF, HHS OIG, CMS, peer-reviewed, and court-filing sources — not from confidential insurer data. Individual outcomes depend on plan type, documentation, state law, and the specific denial reason. This page is informational only and is not legal, medical, or insurance-coverage advice.