How to appeal an Aetna c. difficile infection denial

The framework that applies to your appeal

Federal law gives you the right to a full and fair internal appeal, then an external review by an independent third party.

Aetna-specific note: Owned by CVS Health since 2018. CVS Caremark is the PBM. Aetna ASA administers self-funded ERISA plans. Meritain Health is Aetna's TPA brand.

What Aetna's policy requires for c. difficile infection

Cited policy: Aetna CPB on Bezlotoxumab (Zinplava) for CDI Recurrence Prevention

Adult ≥18 yr receiving standard-of-care antibacterial drug treatment (fidaxomicin or vancomycin) for active CDI. At least ONE high-risk feature: age ≥65, immunocompromised, severe CDI episode, OR ≥1 CDI recurrence within prior 6 mo. Single 10 mg/kg IV infusion concurrent with antibiotic course. Not for treatment of active CDI (adjunct only).

How Aetna denies c. difficile infection — and how to counter it

Where Aetna pushes back: 1) Reserved for ≥3 recurrences (step therapy); 2) Age <65; 3) Not first-line standard of care; 4) Insufficient documentation of risk factor.

Counter-arguments that hold up: Per FDA label (approved Oct 21, 2016) and MODIFY I + MODIFY II (Wilcox NEJM 2017;376(4):305-317), bezlotoxumab is ADD-ON to antibiotic for prevention of recurrence in HIGH-RISK patients — NOT reserved for multiple recurrences. Risk criteria are: age ≥65, immunocompromised, severe CDI, OR ≥1 recurrence within prior 6 mo (ANY ONE qualifies). MODIFY I (n=1452) + MODIFY II (n=1203) showed recurrence 17.4%/15.7% vs 26.7%/25.7% placebo — absolute reduction 9-10%, up to 16-26% in pre-specified high-risk subgroups. Age ≥65 is ONE risk factor, not the only — patients <65 with immunocompromise or prior recurrence qualify equally.

What Aetna typically denies for c. difficile infection

Across Aetna's commercial and Medicare books, denials cluster around a small number of patterns. For c. difficile infection, expect:

• UM-2575 medical necessity denials
• Prior auth absent
• Step therapy on specialty drugs
• Out-of-network ER reduction

Treatments most often denied in this category

These are the c. difficile infection treatments most often flagged for prior auth, step therapy, or medical necessity review:

• Fidaxomicin (Dificid)
• Fidaxomicin extended-pulsed
• Vancomycin PO
• Vancomycin enema
• Bezlotoxumab (Zinplava)
• Rebyota

How to submit the appeal to Aetna

1. Read the denial letter — note the exact denial reason code and the appeal deadline (180 days from the date on the letter).
2. Gather supporting documentation: physician letter of medical necessity, relevant clinical notes, peer-reviewed citations supporting the treatment for your indication, and the policy or coverage document Aetna cited in the denial.
3. File the appeal through Aetna's portal (members: https://www.aetna.com ; providers: https://www.aetnaprovider.com). Standard decision returns within 30 days; expedited urgent appeals return within 72 hours.
4. If denied again, request external review by an independent reviewer within 4 months of the final internal denial. In CT, the state insurance department coordinates external review for fully-insured plans; ERISA self-funded plans use a federal external review through DOL/EBSA.

Clinician or prior-auth team handling this on the practice side? See Aetna's prior-authorization criteria by drug: Aetna PA criteria on ApprovalHelp.