A hot potato: In yet another story about the damaging effects of faulty artificial intelligence, the largest health insurance company in the US, UnitedHealthcare, is being sued over claims it is using a flawed AI model. The system is said to have wrongfully denied health coverage to critical elderly patients and disagreed with doctors' determinations.

The lawsuit filed in the US District Court for the District of Minnesota comes from the estates of two now-deceased men who needed long-term care in post-acute facilities. The families of these men were forced to pay a combined $210,000 out of pocket for their therapy and care before their deaths.

The suit alleges that UnitedHealth repeatedly and wrongfully refused to pay the healthcare claims of the two seniors, who were using the Medicare Advantage Plans. It adds that such incidents have been going on since at least 2020, when UnitedHealthcare acquired post-acute care management firm Navihealth.

The lawsuit followed an investigation by Stat News about the use of an AI algorithm called nH Predict developed by Navihealth. The algorithm is used to anticipate how long patients will stay in rehab following acute injuries, illness, or events. Post-acute care includes the likes of nursing homes and rehab centers. The algorithm reportedly does this by examining a database of medical cases from 6 million patients and estimating a patients' medical requirements and length of stay.

The lawsuit alleges that the AI system has a 90% error rate and overruled the post-acute care opinions of physicians. Furthermore, claims that nH Predict failed to take into account individual patient needs, such as comorbidities (having multiple conditions or diseases) and contracting an illness while staying at a facility.

Another damning section of the suit claims that while only a few patients appealed coverage denials that were based on nH Predict estimates, over 90% of them were reversed through internal appeals processes or federal Administrative Law Judge proceedings.

"Under Medicare Advantage Plans, patients who have a three-day hospital stay are typically entitled to up to 100 days in a nursing home," the lawsuit states, citing Stat's investigation. "With the use of the nH Predict AI Model, [UnitedHealthcare] cut off payment in a fraction of that time. Patients rarely stay in a nursing home more than 14 days before they start receiving payment denials."

Former NaviHealth employees told Stat that once UnitedHealth took over, the focus moved from helping patients to making money and keeping post-acute care times as short as possible.

The UnitedHealth executive overseeing NaviHealth, Patrick Conway, was quoted in a company podcast saying: "If [people] go to a nursing home, how do we get them out as soon as possible?"

nH Predict is still being used today. UnitedHealth's subsidiary Optum Health told Ars Technica: "The NaviHealth predict tool is not used to make coverage determinations. The tool is used as a guide to help us inform providers, families, and other caregivers about what sort of assistance and care the patient may need both in the facility and after returning home. Coverage decisions are based on CMS coverage criteria and the terms of the member's plan. This lawsuit has no merit, and we will defend ourselves vigorously."