May 25, 2026 · ~9 minute read

naviHealth, nH Predict, and the UnitedHealth lawsuit: what it means for your Medicare Advantage appeal

The short version:If your Medicare Advantage plan cut your rehab, nursing-facility care, or other post-acute care short — and you suspect an algorithm was behind it — you're not paranoid. UnitedHealth Group, parent of one of the largest MA insurers in the country, is in active class-action litigation over exactly that. In March 2026, a federal court ordered them to produce internal documents on the algorithm. The case strengthens every appeal where algorithmic decision-making was involved. Here's what's happening, and how to use it.

Why I wrote this

I have an M.S. in Health Informatics, which means I spent years studying exactly how health systems use data and software to make decisions that affect patients. So when the nH Predict lawsuit started developing, I wasn't surprised. I was angry — because I knew this is what happens when algorithms are deployed without enough human judgment left in the loop. And I started getting questions from people whose parents had been cut off from rehab earlier than their doctors recommended. Most of them had no idea an algorithm was behind it.

The thing about algorithmic insurance denials is that they're invisible by design. The denial letter doesn't say “an AI tool scored your case low.” It says “not medically necessary” or “no longer requires skilled care.” If you don't know that something like nH Predict is running in the background of major MA plans, you can't even ask the right questions.

This post is the question you should be asking.

(I'm not a lawyer and this isn't legal advice. Sources for the lawsuit details come from the original court filings in Estate of Lokken v. UnitedHealth Group, KFF, Healthcare Finance News, and Becker's Payer Issues — listed at the bottom.)

What is naviHealth, and what is nH Predict?

naviHealthis a post-acute care management company that UnitedHealth Group acquired in 2020 for $2.5 billion. It's now part of Optum, UnitedHealth's services arm. Its job: help Medicare Advantage plans decide how long an enrollee should stay in a skilled nursing facility, an inpatient rehabilitation facility, or a home-health setting after a hospitalization.

nH Predict is the algorithm naviHealth uses to generate those length-of-stay predictions. According to the class-action lawsuit, it was trained on a database of roughly six million patients and produces estimates for how long a given MA enrollee should need post-acute care after a particular hospitalization or surgery.

How it shows up in practice: when you're discharged from the hospital into a rehab facility, nH Predict generates an estimated length of stay. If your actual care extends beyond the estimate, the MA plan can use the algorithmic prediction as a basis for cutting off coverage — even when your doctor and rehab team say you're not ready to go home.

What the lawsuit alleges

The case is Estate of Lokken v. UnitedHealth Group, Inc., filed November 14, 2023, in the U.S. District Court for the District of Minnesota.

The named plaintiff was Gene Lokken, a 91-year-old Wisconsin man who fractured his leg and ankle in May 2022. UnitedHealthcare covered his rehabilitation for 19 days before nH Predict flagged him for discharge. His family, disagreeing with the algorithm, paid out of pocket for nearly a year until his death.

Core allegations from the complaint:

  • nH Predict's predictions almost always come in lower than what treating physicians recommend
  • UnitedHealthcare uses those lower predictions to cut off coverage even when the treating doctor says the patient isn't ready
  • Court documents allege the algorithm had an error rate exceeding 90% when measured against actual patient outcomes
  • The class action seeks certification on behalf of all Medicare Advantage members whose care was cut short by the algorithm between 2020 and 2024

The lawsuit is still active in 2026. It has not settled.

Recent developments (the part that matters for your appeal)

Two rulings have shifted the case meaningfully.

February 13, 2025 — Judge Tunheim's partial dismissal. The court dismissed five of the seven counts on federal-preemption grounds but allowed the breach of contract and breach of the implied covenant of good faith and fair dealing claims to proceed. Those are exactly the claims that align with what an individual MA enrollee would argue in their own appeal — that the plan contractually promised coverage of medically necessary care and is not delivering it.

March 9, 2026 — Discovery order.A federal magistrate judge ordered UnitedHealth Group to produce an expansive set of internal documents on the nH Predict algorithm, including records on whether the technology was designed to override the clinical judgment of doctors. The court granted plaintiffs' motion to compel discovery across six of seven document categories.

For a patient appealing a UnitedHealth post-acute care denial today, the March 2026 ruling matters even though the case isn't decided. The ongoing discovery is now part of the public regulatory and media environment that MA plans operate in — and it's specifically about whether nH Predict is fit for purpose.

How to spot an algorithmic denial in your own letter

MA plans don't usually say “the algorithm decided” in plain English. They use language that obscures the source of the decision. Watch for:

  • “No longer requires skilled care”— common framing when a plan is cutting off rehab or skilled-nursing coverage. If your doctor disagrees, this is a flag.
  • “Has met the goals of treatment”— without specifying which goals
  • “Care can be safely provided in a lower level of setting” — often used to discharge from inpatient rehab to home
  • “Based on review of medical records and applicable guidelines” — the “applicable guidelines” may be the algorithm's output
  • Direct references to naviHealth or Optum— if your denial letter mentions either, an algorithm was almost certainly involved

If the denial is for post-acute care from a UnitedHealth-affiliated MA plan (UnitedHealthcare, AARP Medicare Advantage), assume nH Predict was involved until shown otherwise.

What to include in your appeal if an algorithm was involved

If you suspect algorithmic decision-making in your denial — especially with UnitedHealthcare for post-acute care — here's what to add to your Level 1 reconsideration:

  1. Request the specific basis for the denial in writing. Under CMS rules, the plan must provide the criteria used. Ask explicitly: “Was an algorithmic tool such as nH Predict used to inform this denial? If yes, please provide the algorithmic output, the data inputs, and the medical reviewer's documentation overriding or accepting it.”
  2. Cite Estate of Lokken v. UnitedHealth Group. You're not litigating the case yourself, but you're putting the plan on notice that you know the legal environment is now actively examining this practice. Reference the November 2023 filing and the March 2026 discovery order.
  3. Get a detailed letter of medical necessity from your treating physician. Specifically, have the physician address why the algorithm's recommendation is wrong for your case. The court allowed the breach-of-good-faith claim to proceed precisely because the algorithm appears to be overriding clinical judgment — your treating doctor's written disagreement is the strongest counter.
  4. Request human review explicitly. Ask for the appeal to be reviewed by a clinician who has not used algorithmic input. Document the request in writing.
  5. File a parallel complaint with your state Department of Insurance. State DOIs are increasingly aware of the algorithmic-denial issue, and a parallel complaint creates an additional paper trail.

Why this matters even if you're not a UnitedHealth member

nH Predict is the most-litigated example of algorithmic claim review, but it's not the only one. Other MA plans use similar tools — sometimes built in-house, sometimes licensed from third parties like MCG Health, Milliman Care Guidelines, or InterQual. The legal exposure created by the nH Predict litigation is shifting how all MA plans think about algorithmic denial review.

What this means for you: even if your MA plan isn't UnitedHealth, asking the same questions in your appeal puts the plan on notice. “Was an algorithmic tool used to inform this denial? Please provide the output and the medical reviewer's documentation.” That single question changes the temperature of the appeal review.

The deadlines, again

If you're appealing a post-acute care denial, the standard CMS appeals timeline applies:

  • 60 days to file your Level 1 reconsideration with the plan, from the date of the denial letter
  • 30 days for the plan to respond (pre-service requests), 60 days (post-service)
  • 72 hours for expedited review if delay would jeopardize your health (post-acute care interruptions often qualify as expedited)

Don't miss the deadline because you're researching the algorithm. File the basic appeal first, supplement with the algorithmic-review argument as you build the case.

About the author

I'm Kov Thirumavalavan. M.S. in Health Informatics, MBA, Staff Systems Analyst at Intuit by day. I built DenyBack— it handles the full 45-day Medicare Advantage escalation for $39 flat. Appeal letter, certified mailings, state DOI complaint, external review request. Done while you focus on actually getting better.

If you're staring at a post-acute care denial that you think an algorithm wrote, you don't have to fight it alone.

Sources

  • Estate of Lokken v. UnitedHealth Group, Inc., Case No. 0:23-cv-03514, U.S. District Court, District of Minnesota — original complaint (November 14, 2023)
  • Order on Motion to Compel Discovery, Estate of Lokken, March 9, 2026 (available via the Georgetown Litigation Tracker)
  • Judge John Tunheim's partial dismissal order, February 13, 2025
  • Healthcare Finance News — “Class action lawsuit against UnitedHealth's AI claim denials advances”
  • Becker's Payer Issues — coverage of the March 2026 discovery order
  • KFF — Medicare Advantage Prior Authorization Denials in 2024 (January 28, 2026)