UnitedHealthcare vs Cigna: Which Denies More Claims?

UnitedHealthcare and Cigna are two of the five largest health insurers in the United States. Combined, they cover tens of millions of Americans. They are also both at the center of major investigations into improper claim denials — UHC for its nH Predict algorithm and Cigna for its PxDX mass-denial system. If you are covered by either insurer and have had a claim denied, understanding what sets these companies apart can help you build a stronger appeal.

UnitedHealthcare: The nH Predict Algorithm

UnitedHealthcare deployed an algorithm called nH Predict to make Prior Authorization Denied: How to Appeal" class="auto-link">prior authorization decisions for post-acute care — skilled nursing facilities, home health, and inpatient rehabilitation. The algorithm was developed by NaviHealth, a subsidiary UHC acquired in 2020.

ProPublica and STAT News investigation in 2023 revealed that the nH Predict tool was overriding treating physicians' recommendations at scale. Patients who had suffered strokes or hip fractures and needed extended rehabilitation were cut off when the algorithm predicted they should have recovered faster than they actually did. Physicians and facilities reported that appeals were routinely denied, and patients were forced to discharge before they were medically ready.

A 2024 federal class action settlement addressed some of these claims, but UHC continues to use algorithmic tools in prior authorization. CMS data showed UHC denied approximately 32% of marketplace claims in 2022 — among the highest rates of any major national insurer.

Cigna: The PxDX Bulk Denial System

Cigna's scandal involved a different kind of automation. A 2023 ProPublica investigation found that Cigna deployed a system called PXDX that allowed physicians employed by the insurer to reject claims en masse without opening individual patient files. Reporters obtained internal records showing that one physician denied 60 claims in a single day, spending an average of 1.2 seconds per case.

The PxDX system matched claim codes against a list of diagnoses Cigna had pre-determined should be automatically rejected. These included claims for certain lab tests, physical therapy, and diagnostic imaging. Because a physician technically "reviewed" each denial, Cigna argued the process was compliant with utilization management requirements — a position regulators strongly disputed.

Cigna reached settlements with multiple state insurance departments following the investigation. Its marketplace Denial Rates by Insurer (2026)" class="auto-link">denial rate in 2022 was approximately 25% according to CMS data — high, but lower than UHC.

Appeal Success Rates: Which Is Easier to Fight?

KFF data on marketplace plans shows that both insurers have appeal success rates in the 40–60% range for internal appeals, which is consistent with the industry average. This means roughly half of all challenged denials are ultimately reversed — a compelling reason to always appeal.

The harder question is whether either insurer is systematically easier to appeal. Healthcare attorneys who work in this space report that UHC's post-acute care denials are among the most difficult to overturn because the nH Predict output is treated as determinative, and reviewers are often reluctant to override the algorithm without very detailed clinical documentation. Cigna's PxDX denials, by contrast, are often reversible with a simple physician letter confirming that the treatment was clinically necessary, because the original denial lacked any individualized review.

Prior Authorization Burden

Both UHC and Cigna maintain extensive prior authorization requirements. UHC's prior auth list has grown significantly in recent years — the company added hundreds of procedures to its prior auth requirements between 2020 and 2023, including some imaging and lab tests that most competitors do not require pre-authorization for.

Cigna similarly expanded its prior authorization program, though it announced in 2023 that it would eliminate prior auth requirements for certain primary care services in response to regulatory pressure. As of this writing, both insurers maintain among the most burdensome prior auth programs in the industry.

How to Appeal Regardless of Your Insurer

Regardless of whether your insurer is UHC or Cigna, the appeal framework is the same. You have the right to:

• A written explanation of the denial including the specific clinical criteria applied
• An internal appeal reviewed by a clinical peer in the same specialty as your treating physician
• An external appeal by an IROs) Explained" class="auto-link">independent review organization (IRO) after the internal process
• Expedited review (within 72 hours) for urgent medical situations

For algorithmic denials specifically, the key argument is that the insurer failed to provide individualized review. Both courts and the ACA mandate individualized clinical review — an algorithm that applies population-level statistics to deny an individual's claim is legally vulnerable.

Fight Back With ClaimBack

Both UHC and Cigna have faced regulatory action for systematic denial practices, which means regulators and courts are already skeptical of their denial processes. If your claim was denied by either insurer, you have a stronger-than-average case for reversal — especially if the denial appears automated or lacks specific clinical justification tied to your individual situation.

ClaimBack walks you through the exact arguments that have succeeded against algorithmic denial programs. We help you document the individualization failure, cite the relevant regulatory standards, and structure your appeal for maximum impact.

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Related Reading

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