Hingten said that, from his company's point of view, all health plans are aggressive about rejecting claims and downgrading reimbursement amounts. "We're really seeing it across all regions and across all service lines," he told the analysts.

Here are some other health care use trends Hingten saw in the first quarter, which ended March 31:

◆ A bad flu season kept the company's primary care offices busy.

◆ Flu reduced use of some types of surgery, either because the patients had the flu or the health care providers had the flu.

◆ Volume for robotic surgery was high, partly because of the company's investments in robotic surgery systems.

◆ Patients made heavy use of high-end heart care services.

◆ Volume for office visits for people with stomach problems was high, but volume for use of gastroenterology procedures was weak.

Community Health Systems thinks the gastroenterology procedure slump is the result of patients with commercial health coverage facing big deductibles and co-payment bills at the beginning of the year.

"There's some apprehension by patients to take that elective care so early in the year, until their co-pays and deductibles have been met," Hingten said. "We'll track that one throughout the year. That was the one area of softness that we did not expect.

Analysts asked the Community Health Systems executives about the impact of the new tariffs, or import taxes, on costs.

Kevin Hammons, the company's president, said tariff news might be one of the factors contributing to the softness in elective procedure volume for patients with commercial health coverage.

Hammons said the company's purchasing strategy could minimize the near-term impact of the tariffs on its own purchasing costs.

Community Health Systems is part of a group purchasing organization that negotiates three-year, fixed-priced contracts with most of its vendors, Hammons said.

About half of the products the company buys are made in the United States, and fewer than 5% of the products come from China, the country facing the highest tariffs, Hammons said.

What it means: Doctors and hospitals often take many months to submit claims to health insurers. That means that the comments people like Hingten make during quarterly calls with securities analysts may be important to help health insurers and the administrators of self-insured employer plans know what's really going on with their "incurred but not reported" claims.

Confusion about incurred-but-not-reported claims became a hot topic in the late 1990s, when problems with IBNR tracking kneecapped a high-flying health insurer, Oxford Health Plans, and, eventually, pushed it to agree to an acquisition by UnitedHealth.

The backdrop: Community Health Systems' CEO gave a peek into what's happening with commercial claims at a time when other big companies are mostly keeping the curtains closed.

UnitedHealth executives talked a little about regulatory pressure on pharmacy benefit managers.

Executives at Elevance — the giant owner of Blue Cross and Blue Shield carriers that was formerly known as Anthem — mentioned, briefly, that employers seem to like its integrated benefits programs and patient advocacy services.

Related: More employers are using patient advocacy services, Elevance CEO says

Executives from Willis Tower Watson said recent turbulence related to U.S. efforts to change its rules for tariffs, or import taxes, has increased demand from employers that want its help with cutting health benefits costs.

But, overall, executives from brokers like Aon and Marsh McLennan have focused on talking about their property and casualty insurance operations, and the health insurers have focused on talking about their Medicare and Medicaid plan businesses.