Aetna vs Cigna: Prior Auth Burden, Denial Rates, and Appeal Comparison

Aetna (now owned by CVS Health) and Cigna (recently rebranded as The Cigna Group) are two of America's largest commercial health insurers. If you are choosing between them or currently covered by one and dealing with a denial, understanding how each company handles claims can significantly affect your outcome. By available data, Cigna denies a higher percentage of claims than Aetna and has been more aggressively criticized for systemic bulk-denial practices — but both companies have serious documented problems that directly affect members.

Why Insurers Deny Claims: Aetna vs Cigna Patterns

Both Aetna and Cigna deny claims under the same broad categories, but with distinct patterns:

• Aetna: Marketplace claim Denial Rates by Insurer (2026)" class="auto-link">denial rate approximately 22–24% in recent CMS data; 2022 California court finding that Aetna applied medical necessity criteria more restrictive than required under California law and Mental Health Parity Act (MHPAEA) Explained" class="auto-link">MHPAEA; 2020 class action settled alleging a medical director reviewed and denied claims without reading patient files
• Cigna: Marketplace denial rate approximately 25% in 2022; the ProPublica-exposed PxDX system allowed employed physicians to reject claims in bulk with documented average of 1.2 seconds per case; pre-identified diagnosis codes were auto-denied with largely nominal physician review
• Prior Authorization Denied: How to Appeal" class="auto-link">Prior authorization burden: AMA's Prior Authorization Physician Survey consistently ranks Cigna's prior auth burden among the highest in the industry, with less user-friendly portals, longer response times, and more frequently denied peer-to-peer review requests
• Mental health parity: Both insurers have faced significant legal challenges under MHPAEA §1185a (29 U.S.C. §1185a) — Aetna's 2022 California court loss was specifically over applying more restrictive mental health criteria than comparable medical/surgical services; Cigna has faced similar parity complaints

For consumers: by available data, Cigna denies a higher percentage of claims and has been more explicitly criticized for institutional denial at scale. Aetna's prior authorization process has been rated somewhat more responsive, with more consistent same-specialty clinical reviewer assignment on first appeal.

How to Appeal

Step 1: Identify the Specific Denial Ground and Clinical Criteria

Both Aetna and Cigna are required by ACA §2719 (42 U.S.C. §300gg-19) to provide a written denial with specific clinical criteria cited. For Aetna, obtain the relevant CPB at aetna.com/cpb. For Cigna, obtain the relevant coverage policy at cigna.com. Read each document in full — not just the summary — and identify which specific criterion the insurer determined you did not meet.

Step 2: Request the Complete Claims File

Under ERISA §1133 (29 U.S.C. §1133), both insurers are required to provide the complete claims file including the clinical criteria applied, the reviewer's credentials, and the specific reason for denial. Review the file for procedural deficiencies — Cigna's internal appeal process has been criticized for using overly generic denial language that itself may violate ERISA §1133.

Step 3: Request Peer-to-Peer Review

For Aetna, call 1-800-872-3862. For Cigna, call 1-800-244-6224. Request that the reviewing clinician have specialty credentials matching your diagnosis. An internist reviewing a neurosurgical request is inappropriate. Document the reviewer's name, credentials, and any commitments made after the call.

Step 4: File the Internal Appeal With a Physician Letter

ACA §2719 requires both insurers to respond within 30 days for non-urgent pre-service appeals, 60 days for post-service appeals, and 72 hours for urgent care appeals. Assign a different reviewer than the original decision-maker. Your physician's letter must address the insurer's specific clinical criteria language — not just provide a general statement of medical necessity — and cite relevant specialty society guidelines showing the insurer's criteria are more restrictive than accepted clinical standards.

Step 5: Invoke MHPAEA If the Denial Involves Behavioral Health

Under MHPAEA §1185a (29 U.S.C. §1185a), both Aetna and Cigna are prohibited from applying prior authorization requirements or treatment limitations on mental health or substance use disorder benefits that are more restrictive than those applied to comparable medical and surgical benefits. For behavioral health denials, a parity argument — specifically challenging the non-quantitative treatment limitations applied — is one of the strongest legal tools available.

Step 6: Escalate to External Independent Review: Complete Guide" class="auto-link">External Review and Regulatory Complaints

For fully insured plans, file with your state's certified IROs) Explained" class="auto-link">Independent Review Organization. External review organizations have no financial relationship with either insurer and reverse denials at rates consistently higher than internal appeal success rates. File a complaint with your state insurance commissioner (fully insured plans) or the Department of Labor (ERISA plans) to create regulatory pressure.

What to Include in Your Appeal

• Complete denial letter with specific clinical criteria or CPB/coverage policy cited, plus the relevant clinical policy document from aetna.com/cpb or cigna.com
• Physician letter of medical necessity addressing each denial criterion and citing specialty society guidelines showing the insurer's criteria are more restrictive than accepted clinical standards
• Evidence that insurer criteria deviate from USPSTF, NCCN, AHA, or other authoritative guidelines, along with prior treatment records documenting step therapy compliance
• MHPAEA parity argument and comparative data if behavioral health is involved (29 U.S.C. §1185a)
• Peer-to-peer review notes documenting the reviewer's credentials and any commitments made

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Related Reading

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• Internal vs External Insurance Appeal