Does Aetna deny a lot of claims? Yes — Aetna denies approximately 22% of all in-network claims, higher than the industry average of 19.1%. In some states, Aetna HMO denial rates reach 39.4%. For Medicare Advantage prior authorizations, Aetna denies 11.9% of requests. The good news: over 80% of Aetna denials are overturned on appeal when properly documented, and practices using AI-powered appeals achieve 89% success rates.
Aetna Denial Rate: The Full Picture
Aetna is one of the largest health insurers in the United States, covering over 34 million members across commercial, Medicare Advantage, and Medicaid plans. But their denial rates consistently rank above the national average.
Here's what the data shows across every plan type:
| Plan Type | Denial Rate | Data Source | Year |
|---|---|---|---|
| ACA / Marketplace (all claims) | 22% | CMS Transparency in Coverage PUF | 2024 |
| HMO Plans (Connecticut) | 39.4% | CT Insurance Department | 2023 |
| Indemnity Plans (Connecticut) | 28.2% | CT Insurance Department | 2023 |
| Medicare Advantage (prior auth) | 11.9% | CMS / KFF Analysis | 2024 |
| Medicaid MCO (West Virginia) | 13.7% | State Medicaid Data | 2024 |
| Industry Average (ACA) | 19.1% | CMS Transparency in Coverage PUF | 2024 |
Key takeaway: Aetna's 22% overall denial rate is 15% higher than the 19.1% industry average. For HMO plans in states like Connecticut, the denial rate nearly doubles to 39.4%.
Aetna Exiting ACA Marketplace in 2026
Aetna announced it will no longer offer individual or family ACA-compliant plans as of January 1, 2026, affecting roughly 1 million members across 17 states. If you're transitioning to a new insurer, check your new plan's denial rates in the comparison table below.
How Aetna Compares to Other Insurance Companies
Aetna's denial rate sits in the middle of the pack nationally — below the worst offenders like Oscar and Molina, but well above the best performers like Kaiser.
| Insurance Company | Overall Denial Rate | Medicare Advantage PA Denial Rate | Rank |
|---|---|---|---|
| Oscar Health | 25–26% | N/A (limited MA presence) | #1 (Highest) |
| Molina Healthcare | 22% | 7.2% | #2 |
| Aetna (CVS Health) | 22% | 11.9% | #3 |
| Ambetter (Centene) | 20–21% | 9.8% | #4 |
| UnitedHealthcare | 19–33%* | 12.8% | #5 |
| Cigna | 17–30%* | 8.1% | #6 |
| Blue Cross Blue Shield | 15–20%* | Varies by affiliate | #7 |
| Humana | 14–18% | 5.8% | #8 |
| Elevance Health | 12–16% | 4.2% | #9 |
| Kaiser Permanente | 6% | 10.1% | #10 (Lowest) |
*Ranges reflect variation across plan types and states.
What stands out:
- Oscar Health has the highest denial rate at 25–26% of all in-network claims
- Kaiser Permanente has the lowest at just 6% — nearly 4x lower than Aetna
- For Medicare Advantage prior authorizations, UnitedHealthcare (12.8%) and Aetna (11.9%) deny the most, while Elevance (4.2%) denies the fewest
- 83.2% of Medicare Advantage denials are overturned on appeal — suggesting many initial denials shouldn't have happened
Why Does Aetna Deny So Many Claims?
Aetna denials fall into five primary categories:
| Denial Reason | % of Aetna Denials | Overturn Rate on Appeal |
|---|---|---|
| Prior authorization not obtained | 35% | 60–70% |
| Medical necessity disputed | 28% | 75–85% |
| Out-of-network provider | 18% | 40–50% |
| Experimental / investigational | 12% | 55–65% |
| Coding or documentation errors | 7% | 85–95% |
Medical necessity denials have the highest overturn rate because Aetna's Clinical Policy Bulletins (CPBs) often apply stricter criteria than peer-reviewed medical guidelines. When you cite both the CPB and supporting literature in your appeal, reviewers frequently reverse the decision.
Coding and documentation errors are the easiest to overturn — these are administrative mistakes, not clinical disagreements. A corrected claim submission resolves most of these without a formal appeal.
Aetna Denial Rates by State
Denial rates vary significantly depending on where you practice. State insurance regulations, plan mix, and Aetna's local network strategies all influence how aggressively claims are denied.
| State / Region | Aetna Denial Rate | Plan Type | Notes |
|---|---|---|---|
| Connecticut | 39.4% | HMO | Highest documented state rate |
| Connecticut | 28.2% | Indemnity | Second-highest rate by plan type |
| West Virginia | 13.7% | Medicaid MCO | Aetna Better Health of WV |
| National Average | 22% | ACA Commercial | All states combined |
| Hawaii (all insurers) | 26.9% | All plans | Highest state denial rate overall |
| South Dakota (all insurers) | 5.4% | All plans | Lowest state denial rate overall |
Connecticut Deep Dive
Connecticut's Insurance Department found that Aetna had the highest HMO denial rate of any insurer at 39.4%, followed by Harvard Pilgrim (38.8%) and ConnectiCare (33.6%). Despite these high denial rates, Aetna reversed only 10 of its 181,642 denials through its internal appeals process — a reversal rate of just 0.005%.
This Connecticut data reveals a critical pattern: Aetna rarely reverses denials through its own internal process. This means external appeals — including independent review and state insurance department complaints — are essential for providers fighting Aetna denials.
Aetna Medicare Advantage: Prior Authorization Denial Data
Medicare Advantage prior authorization denials deserve special attention because CMS publishes detailed data on every MA insurer.
In 2024, Medicare Advantage insurers processed nearly 53 million prior authorization requests nationwide. Here's how Aetna stacked up:
| Metric | Aetna | Industry Average | Best Performer |
|---|---|---|---|
| Prior Auth Denial Rate | 11.9% | 9.2% | Elevance (4.2%) |
| Avg Requests Per Enrollee | 1.2 | 1.0 | Kaiser (0.6) |
| Appeal Overturn Rate | 83%+ | 83.2% | Similar across insurers |
| Partially Approved Rate | ~15% | ~12% | Varies |
The appeal overturn rate is the most important number here. When 83% of appealed denials get reversed, it signals that initial denial decisions are often wrong. CMS has proposed new rules to reduce unnecessary prior authorization barriers, but these changes are still being implemented.
→ Automate Your Aetna Medicare Advantage Appeals
How to Fight Aetna Denials: What the Data Tells Us
The statistics point to a clear strategy for maximizing your appeal success rate:
1. Always Appeal Medical Necessity Denials
With a 75–85% overturn rate, medical necessity denials are the most winnable category. Cite Aetna's own CPBs alongside peer-reviewed literature and CMS coverage determinations (LCDs/NCDs) to build an evidence-based case.
2. Request Peer-to-Peer Review Early
Aetna allows providers to speak directly with their reviewing physician before or during the appeal process. Peer-to-peer reviews resolve many denials without a formal written appeal — saving weeks of processing time.
3. Don't Rely on Aetna's Internal Process Alone
Connecticut data shows Aetna reverses less than 0.01% of denials internally. If your internal appeal is denied, always escalate to external review through your state insurance department. External review panels overturn 56–60% of denials that survive internal appeals.
4. Track Your Denial Patterns
If you're seeing high denial rates from Aetna for specific CPT codes or procedures, you likely have a systemic issue — not isolated bad luck. Common patterns include:
- Step therapy denials for specialty medications
- Prior auth denials for imaging (MRI, CT) without sufficient clinical documentation
- Medical necessity denials for physical therapy beyond initial evaluation visits
- Experimental/investigational denials for newer FDA-approved treatments
5. Use AI-Powered Appeals for Consistency
Manual appeals take 45–90 minutes each and have inconsistent success rates depending on who writes them. AI-powered appeal tools analyze Aetna's CPBs, match clinical documentation to denial criteria, and generate evidence-based appeals in minutes — with 89% success rates.
→ See How Muni Appeals Automates Aetna Denials
Aetna Appeal Deadlines and Process
If you're filing an appeal against an Aetna denial, here are the key deadlines:
| Plan Type | Appeal Deadline | Decision Timeline | Where to File |
|---|---|---|---|
| Commercial (standard) | 180 days from denial | 30 calendar days | Availity portal or fax |
| Commercial (expedited) | 180 days from denial | 72 hours | Fax: 1-859-425-3380 |
| Medicare Advantage | 60 days from denial | 30 calendar days | Aetna MA Appeals Dept |
| Medicare Advantage (expedited) | 60 days from denial | 72 hours | Call 1-800-756-7039 |
| Medicaid | State-specific | State-specific | Varies by state |
Pro tip: The clock starts on the date of the denial letter, not when you receive it. If you're within 30 days, always request expedited review for urgent medical situations.
For detailed filing instructions, see our complete guide: Insurance Appeal Deadlines by Company. For a full step-by-step walkthrough of the 2026 appeal process — including Aetna's new Level of Severity inpatient payment policy — see How to Appeal Aetna Denials 2026.
Frequently Asked Questions
Does Aetna deny a lot of claims?
Yes. Aetna denies approximately 22% of all in-network claims, which is above the national average of 19.1%. For HMO plans in some states, denial rates reach as high as 39.4%. However, over 80% of Aetna denials can be overturned on appeal with proper documentation.
What is Aetna's denial rate compared to other insurers?
Aetna ranks #3 among major insurers for highest denial rates, behind Oscar Health (25–26%) and tied with Molina Healthcare (22%). Kaiser Permanente has the lowest denial rate at 6%. For Medicare Advantage prior authorizations specifically, Aetna denies 11.9% — the second-highest rate after UnitedHealthcare (12.8%).
How often does Aetna deny prior authorization requests?
For Medicare Advantage plans, Aetna denies 11.9% of prior authorization requests based on 2024 CMS data. For commercial plans, prior authorization denial rates are higher — approximately 25–30% depending on the service type and state.
What percentage of Aetna appeals are successful?
For Medicare Advantage plans, 83% of appealed Aetna denials are overturned. For commercial plans, the overturn rate ranges from 60–85% depending on the denial reason. Medical necessity appeals have the highest success rate (75–85%), while out-of-network denials have the lowest (40–50%).
Is Aetna the worst insurance company for denials?
No — Oscar Health (25–26%) and Molina Healthcare (22%) match or exceed Aetna's overall denial rate. However, Aetna's HMO denial rates in certain states (39.4% in Connecticut) are among the highest documented for any insurer. Aetna also has an extremely low internal appeal reversal rate, making external review essential.
Why did Aetna deny my claim for medical necessity?
Aetna uses proprietary Clinical Policy Bulletins (CPBs) to evaluate medical necessity. These criteria are often stricter than peer-reviewed guidelines or CMS coverage policies. If your claim was denied for medical necessity, your appeal should cite both the specific CPB and supporting literature showing the treatment meets accepted standards of care.
The Bottom Line
Aetna's 22% denial rate means roughly 1 in 5 claims gets denied — and in some states and plan types, it's closer to 2 in 5. But the data also shows that the vast majority of these denials can be overturned:
- 83% of Medicare Advantage denials reversed on appeal
- 75–85% of medical necessity denials overturned
- 85–95% of coding/documentation denials resolved
The key is actually filing the appeal. Only 11% of denied claims ever get appealed, which means insurers like Aetna collect billions in denied claims that would have been paid if challenged.
Don't leave money on the table. Every Aetna denial deserves an appeal.
→ Start Automating Your Aetna Appeals Today
Sources: CMS Transparency in Coverage Public Use File (2024), KFF Medicare Advantage Prior Authorization Analysis (2024), Connecticut Insurance Department (2023), MoneyGeek ACA Claim Denial Rankings (2026), Aptarro US Healthcare Denial Statistics (2026)