Humana vs UnitedHealthcare Medicare Advantage: Denial Rates by Insurer (2026)" class="auto-link">Denial Rates and OIG Findings

Medicare Advantage (MA) plans are sold by private insurers who contract with CMS to provide Medicare benefits. Humana and UnitedHealthcare are the two largest Medicare Advantage insurers by enrollment — together covering more than 30 million MA beneficiaries. Both have been subjects of significant federal scrutiny over improper denials. If you are enrolled in either plan, here is what federal audit data reveals.

The OIG Reports: What They Found

The Office of Inspector General (OIG) of the Department of Health and Human Services has issued multiple reports analyzing Medicare Advantage denials. The findings are stark. A 2022 OIG report found that MA organizations denied Prior Authorization Denied: How to Appeal" class="auto-link">prior authorization requests that met Medicare coverage criteria at a meaningful rate, and that some of those denials were reversed on appeal — suggesting the original denials were improper.

A 2023 OIG report specifically examining prior authorization denials found that the most common reasons for overturned denials included:

• The insurer had applied more restrictive clinical criteria than traditional Medicare would use
• The insurer had failed to review relevant clinical information in the patient's file
• The denial letter failed to explain the clinical basis for the decision

Both Humana and UHC were among the MA organizations with high rates of prior authorization denials in the OIG's samples.

UnitedHealthcare Medicare Advantage: nH Predict and CMS Action

UHC's MA plans have faced particular scrutiny for the nH Predict algorithm used to make post-acute care determinations. In 2023, a federal court class action found that UHC had systematically used the algorithm to deny skilled nursing facility and inpatient rehabilitation claims at rates that exceeded what the algorithm's own confidence intervals supported.

CMS responded by issuing guidance in 2023 clarifying that MA plans must make prior authorization decisions based on individual clinical circumstances, not algorithm-generated population statistics. CMS also proposed new regulations requiring MA plans to document the basis for prior authorization denials more specifically.

UHC's overall MA star rating has fluctuated in the 3.5–4.0 range. Its contract renewal has been subject to CMS performance monitoring related to its appeals and grievances record.

Humana Medicare Advantage: Denial Rates and Star Ratings

Humana's MA business is the second largest in the country. The company has consistently maintained higher average star ratings than UHC — many Humana MA plans are rated 4.0 or 4.5 stars, which reflects better performance on CMS's process and outcome metrics including appeals and grievances.

However, high star ratings do not mean Humana never improperly denies claims. The OIG's 2022 report found Humana among the MA organizations with denial patterns warranting further scrutiny, particularly for home health and skilled nursing facility prior authorizations.

Humana's denial rate for prior authorization requests in its MA plans has been reported at approximately 18% in audited samples — lower than some competitors but well above the traditional Medicare rate, which does not require prior authorization for most covered services.

Traditional Medicare vs Medicare Advantage: The Core Issue

The fundamental tension in Medicare Advantage is that traditional Medicare does not use prior authorization for most services. When you enroll in a Medicare Advantage plan, you give up that feature in exchange for additional benefits like dental, vision, and gym memberships. But you also subject yourself to prior authorization requirements that can delay or deny care that traditional Medicare would cover automatically.

A 2023 Senate Finance Committee report found that MA denials for post-acute care were disproportionately affecting the sickest beneficiaries — the patients who most needed the care being denied. Both Humana and UHC were specifically mentioned in the committee's findings.

How to Appeal a Medicare Advantage Denial

Medicare Advantage appeals follow a specific federal process:

1. Redetermination: Request a redetermination from the MA plan within 60 days of the denial
2. Reconsideration: If denied again, request reconsideration by a Qualified Independent Contractor (QIC) — this is independent of the insurer
3. ALJ Hearing: If the amount in controversy is at least $180 (as of 2024), you can request a hearing before an Administrative Law Judge
4. Medicare Appeals Council: Review by the Departmental Appeals Board
5. Federal Court: Judicial review if all administrative remedies are exhausted

For urgent situations, you can request an expedited appeal, which the MA plan must resolve within 72 hours. If you disagree with a coverage termination, you can request a fast appeal to continue receiving services while the appeal is pending.

Fight Back With ClaimBack

Medicare Advantage denials are among the most legally actionable denials in the insurance system, because federal law is unusually specific about what MA plans must and cannot do. If your Humana or UHC Medicare Advantage plan denied a claim that traditional Medicare would have covered, that denial may be legally deficient on its face.

ClaimBack helps you navigate the Medicare Advantage appeal process, identify whether your insurer applied criteria more restrictive than Medicare standards, and build a complete appeal record through the ALJ level if necessary.

Start My Free Appeal →

Related Reading

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