The use of artificial intelligence by hospitals and health insurers is escalating their longstanding feud over paying for medical care. Artificial intelligence is intensifying the battles between insurers and hospitals. In the latest sign that artificial intelligence is fueling higher health care costs, a group of insurers released a report Thursday claiming that hospitals’ use of A.

I. was responsible for nearly $1 billion in additional expenses over two years. Using codes for various medical conditions, hospitals submitted claims for tens of thousands of patients that described their illnesses as more complex in 2024 and 2025 than in 2023. Despite the added conditions, there was no evidence that the patients had received different treatment from the hospitals, according to the analysis by the Blue Cross Blue Shield Association, which represents state Blue Cross plans.

Using A. I. tools, hospitals are collecting more information about their patients, and submitting bigger claims, the association said. “Coding is changing because of this technology,” said Luke Chalker, a senior vice president at the association. By describing patients as having more complicated conditions and adding a secondary diagnosis, like anemia or low sodium, the hospitals were paid an average of nearly $12,000 more per case.

A. I. has become an increasingly powerful tool in the continuing coding wars between insurance companies on one side and hospitals and doctors on the other. Hammered by lawmakers at congressional committees, company executives and hospital officials have been pointing their fingers at each other for spiraling health costs. Dr. David Brailer, a health technology executive and former government health official, said A.

I. would lower the costs of the weapons in these battles over billing. In a recent piece in Health Affairs, an academic journal, he predicted A. I. would be likely to increase overall health care spending. Dr. Brailer, who oversaw the George W.

Bush administration’s push to encourage the adoption of electronic health records, said hospitals had quickly seized on that new technology to bill more by being better able to document their care. “I don’t think there is anything intrinsically different in A. I. that will escape the market forces,” he said. Just as providers are using sophisticated A.

I. tools to say their patients are sicker, insurance companies have been accused of using the tools to delay or deny care. The companies have come under intense criticism for their use of A. I. when requiring prior approval of treatments and medicines.

A new pilot program in Medicare that relies on sophisticated technology to help determine whether certain kinds of care should be covered has come under attack by some lawmakers. While Medicare and the insurers insist they never deny care without oversight from a medical professional, the tools are adding to the overall friction between the parties. Patients are often caught in the middle, left with unpaid bills or denied care. “All the insurers are using A.

I. to scan our charts to look for claims to deny. For the same reason, we’re looking at the same charts today,” said Dave Mazurkiewicz, the chief financial officer for Mc Laren Health Care, a small Michigan health system. Mc Laren buys A.

I. technology from Smarter Dx, which takes a cut of the additional revenues it generates. Mr. Mazurkiewicz said A. I. helped a doctor better document a patient’s condition, like suggesting that the physician record the severity of a patient’s kidney disease to justify a higher payment for care. If a doctor ordered a test, the tool might remind the physician that failing to document a potential diagnosis from that test would make it unbillable.

Mc Laren has increased its revenue by $1 million a month through its adoption, adding to its small profits, according to Mr. Mazurkiewicz.