UnitedHealthcare, the nation’s largest insurer, will halt the sharing of future data with an influential Washington, D.C., nonprofit group, a move that researchers say could hamper efforts to understand what’s driving the spike in U.S. health care costs.

For a number of years, Minnetonka-based UnitedHealthcare has been a prominent supporter of a group called the Health Care Cost Institute (HCCI), which in turn has helped researchers use data from United and other national health insurers to study everything from spiking insulin costs and hysterectomy trends to the market power of hospitals.

One influential study in 2015 challenged conventional wisdom by showing how regions like Rochester, Minn., might look efficient in terms of Medicare costs, but not for patients with private insurance.

“The Health Care Cost Institute and UnitedHealthcare are sunsetting their data collaboration relationship agreement, that has provided United’s deidentified insurance claims data for analyses of U.S. health care spending, utilization, and market performance,” the group said in a statement.

In a statement, the parent company of UnitedHealthcare said it has appreciated the partnership as well as research contributions from the group. At the same time, the company said it is now focusing on other research partnerships, pointing to an ongoing collaboration with Mayo Clinic on a project called OptumLabs and recent research on diabetes with Northwestern University.

“There are a number of different ways that we approach research, and we’re committed to that,” said L.D. Platt, a spokesman for UnitedHealth Group.

HCCI coordinates data-sharing agreements with universities and selected organizations so researchers have access to data that doesn’t reveal patient identities from four health insurers — Aetna, Humana, Kaiser Permanente and UnitedHealthcare. It’s been one of the most comprehensive data sets for understanding cost trends among people with employer-sponsored insurance, which is the largest source of coverage in the United States.

“The loss of the UnitedHealthcare data … is a major setback to our attempts to better understand what is driving health care costs,” said Katherine Hempstead of the Robert Wood Johnson Foundation, a New Jersey-based nonprofit that has funded several research projects using Health Care Cost Institute data. “The demand for that data has been very high, so this creates a big hole, and it’s not clear whether or how it will be filled.”

The nonprofit group said it will approve up to 10 new external research projects incorporating UnitedHealthcare’s data between now and the end of June. The new research is in addition to any projects approved under an ongoing program with the Robert Wood Johnson Foundation. What’s more, all new and existing research partners will have the option to continue to access HCCI’s combined data set, including United data, until the end of 2022.

Even so, the end of the data-sharing agreement with UnitedHealthcare is a setback, said Niall Brennan, the president and chief executive of HCCI. The existing data set has UnitedHealthcare information through 2017, but won’t have new data from the company for outside researchers.

“United are a big company,” Brennan said. “When you take a chunk of lives out of that, the research community will be the worse for it and our understanding of the health care system, particularly as it relates to employer-sponsored coverage, is likely going to suffer.”

Brennan said he’s reaching out to other health insurers about joining the collaborative effort to help fill the void. In addition, he said the Kentucky-based health insurer Humana currently has committed to sharing data only through the end of 2019.

“I’m obviously hopeful that we can change their mind in that regard,” Brennan said. “Aetna and Kaiser continue to be solid and enthusiastic supporters of HCCI and its mission.”

HCCI’s scope is national, but has had several connections to Minnesota that go beyond UnitedHealthcare’s involvement.

University of Minnesota health economist Stephen Parente was on the board of HCCI. When Scott Leitz, the second chief executive of the state’s MNsure exchange, left state government, he took a job at HCCI.

And then there’s the 2015 report, which challenged previous studies about where health care in the U.S. is most efficient — including, to a degree, the thrifty reputation of health care in Minnesota. Many of those studies on efficiency were based on Medicare data, but the 2015 report drew on HCCI data and generated a very different picture.

“Many of the regions cited by policymakers as models for the nation, like Grand Junction, Colo., Rochester, Minn., and La Crosse, Wis., have extremely high spending for the privately insured,” said Zack Cooper, a Yale University economist, in a statement at the time. “Simply put, we cannot use these areas to shape federal policy.”

The loss of UnitedHealthcare’s data going forward means studies might not be so easily generalized across the entire market for employer-sponsored health insurance, said Katy Kozhimannil, a University of Minnesota researcher who’s used HCCI data to study health costs with childbirth. A smaller data set also means researchers might have a harder time using it to study rare conditions, she said.

“It really gave us the private health insurance market with regard to childbirth,” Kozhimannil said. “That’s a hard thing to get in other places.”


Twitter: @chrissnowbeck