Medicare Advantage vs Original Medicare: Denial Rates by Insurer (2026)" class="auto-link">Denial Rates and Appeal Rights

One of the most consequential health insurance decisions a Medicare-eligible person makes is whether to enroll in traditional Medicare or a Medicare Advantage (MA) plan. The coverage looks similar on paper. In practice, Medicare Advantage members face significantly higher denial rates and a more complex appeal process. Here is what the data shows and what your rights are.

The Core Difference: Prior Authorization Denied: How to Appeal" class="auto-link">Prior Authorization

Traditional Medicare — Parts A and B administered by the federal government — does not require prior authorization for most covered services. If your doctor determines that a service is medically necessary and it falls within Medicare's coverage criteria, it is generally covered without advance insurer approval.

Medicare Advantage plans, sold by private insurers under contract with CMS, are allowed to require prior authorization as a condition of coverage. And they use this authority extensively.

A 2022 Senate Finance Committee report found that MA plans denied 1.5 million prior authorization requests in 2020 — and that when those denials were appealed and reached the point of independent medical review, they were overturned at rates suggesting a significant portion of the original denials were inappropriate. The committee found that approximately 75% of fully adjudicated denials that reached ALJ review were reversed in the patient's favor.

CMS Audit Data: What the Numbers Show

The Office of Inspector General has issued multiple reports analyzing MA denial practices. Key findings from 2022 and 2023 OIG reports:

• MA organizations denied approximately 13% of prior authorization requests for services that met Medicare coverage criteria in one audited sample
• For post-acute care (skilled nursing facility, home health, inpatient rehabilitation), denial rates were significantly higher — some MA plans denied post-acute care at rates exceeding 20%
• The most common reason for inappropriate denials was applying clinical criteria more restrictive than Medicare's own coverage standards
• 18% of denied requests in one sample involved services that should have been covered under Medicare rules

These findings have led CMS to implement new regulations for the 2024 and 2025 plan years requiring MA plans to document the basis for prior authorization denials in greater detail and to align prior authorization criteria more closely with traditional Medicare coverage standards.

Which MA Plans Have the Worst Records?

The OIG and CMS have not published fully public plan-level denial rankings in a format that allows precise comparisons. However, the Senate Finance Committee report and independent analysis from the Center for Medicare Advocacy have identified UnitedHealthcare, Humana, and Elevance Health as among the MA organizations with the most problematic denial patterns in specific service categories.

UHC's use of the nH Predict algorithm for post-acute care generated the most specific legal action. Class action litigation established that UHC had systematically denied skilled nursing facility coverage using algorithm output that did not reflect individual clinical circumstances.

Humana's MA plans have been cited for home health denial rates above what original Medicare would generate for the same population.

The Medicare Advantage Appeal Process

MA appeals follow a specific federal process that differs from commercial insurance appeals:

1. Organization Determination: Initial coverage decision by the MA plan
2. Redetermination: Internal appeal to the MA plan — must be decided within 30 days (standard) or 72 hours (expedited)
3. Reconsideration: Review by a Qualified Independent Contractor (QIC) — this is independent of the MA plan. Must be decided within 30 days (standard) or 72 hours (expedited)
4. ALJ Hearing: Administrative Law Judge hearing if the amount in controversy is at least $180 (2024 threshold)
5. Medicare Appeals Council: Further administrative review
6. Federal District Court: Judicial review

For beneficiaries facing service terminations (hospital discharge, SNF discharge, home health termination), you have the right to a "fast appeal" that requires the QIC to decide within 72 hours. You also have the right to continue receiving the service while the appeal is pending — the insurer cannot cut off ongoing services before the appeal is decided.

Original Medicare: The BFCC-QIO Process

Traditional Medicare uses a different mechanism for coverage disputes involving service terminations. Beneficiary and Family Centered Care Quality Improvement Organizations (BFCC-QIOs) handle appeals for inpatient hospital, SNF, home health, and outpatient rehabilitation service terminations under traditional Medicare.

If your hospital is discharging you and you believe the discharge is premature, you can appeal to your BFCC-QIO the same day — and your stay will be covered while the appeal is pending. This "immediate review" right applies in traditional Medicare and is a critical protection that many beneficiaries do not know they have.

How to Appeal a Medicare Advantage Denial

The most important steps for MA denial appeals:

• Request the denial notice in writing if you did not receive one
• File for expedited review whenever the medical situation is urgent
• At the QIC reconsideration stage, submit all clinical documentation — this is the last stage where you can add new evidence easily
• If you reach the ALJ stage, you may have the right to an in-person or video hearing
• Keep detailed records of all communications, authorizations, and medical records throughout the process

Fight Back With ClaimBack

Medicare Advantage denial rates are consistently higher than traditional Medicare — and the appeal process, while structured and federally enforced, has specific requirements that must be followed precisely to preserve your rights. ClaimBack helps MA beneficiaries navigate each step of the appeal process, from the initial redetermination through QIC reconsideration, ensuring that the clinical and regulatory record is complete before escalation.

If your MA plan denied care that traditional Medicare would have covered, you have a strong case for reversal.

Start My Free Appeal →

Related Reading

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• Common Reasons Insurance Claims Are Denied