The nation’s largest health insurer and the University of California Health system are joining forces to create a new health plan option for employers and expand research into patient data.

Under the 10-year partnership unveiled Thursday, UnitedHealth Group Inc. and the UC system will form an accountable care organization that will be offered to large, self-funded employers statewide. In accountable care organizations, or ACOs, physicians, hospitals and an insurer work together to coordinate care, control spending and share savings.

The for-profit insurer will also open a research lab in the San Francisco area early next year offering researchers at the state-run health system access to a huge national database of patient records.

The collaboration comes as hospital systems and insurers are under increasing pressure from employers, government health programs and their competitors to forge new alliances aimed at improving care and cutting costs. It also reflects the growing importance of data mining to achieve those goals by identifying disease earlier and finding more effective treatments.

The deal marks UnitedHealth’s continued interest in growing its California business despite its decision in May to leave the state’s health insurance exchange.

The company’s Optum unit was recently awarded a five-year contract to manage pharmacy benefits for the California Public Employees’ Retirement System, and UnitedHealth is expanding its presence in Medi-Cal, the state’s Medicaid program. The company said it now serves more than 3.5 million Californians.

The UC system runs five academic medical centers in Los Angeles, San Francisco, San Diego, Irvine and Davis, including hospitals, medical groups, clinics and other outpatient facilities. They will continue to work with other insurers such as Anthem Inc. and Blue Shield of California as network providers and in other ACOs.

But UnitedHealth offered several advantages compared to its rivals in terms of data-mining capabilities and administrative support for hospitals and physician offices through its consulting unit, said David Kraus, chief contracting and clinical strategy officer for the UC Health system.

“What was unique about UnitedHealth is they are more than just a health plan,” Kraus said. “This collaboration helps us advance things quicker.”

Kraus said the university system and UnitedHealth want to learn from the mistakes of earlier ACOs and offer employers a more centralized approach that can tap into real-time data as patients move through the health care system.

“A lot of employers have a physical health product unrelated to a mental health product unrelated to their wellness program, which is completely unrelated to the pharmacy benefit. We think it needs to be all together, and we get to build this ACO from the ground up,” Kraus said.

The financial terms of the partnership weren’t disclosed. Kraus said a joint governing board will establish the specific financing for individual projects and determine how much each organization contributes.

“We will look at pilots and talk about which ones to invest in and where,” Kraus said. “It could be 80 percent-20 percent or 60-40. We haven’t boxed ourselves into a preordained structure.”

Steve Valentine, vice president and West Coast consulting leader at the health care firm Premier Inc., said the deal brings together two highly regarded organizations, but he said some employers chafe at the high cost of UC facilities.

“UC has to address its whole cost structure,” Valentine said. “They tend to be more expensive so they will need to address pricing to be competitive.”

UnitedHealth is playing catch-up in a crowded market. Anthem, the nation’s second-largest health insurer, has been the dominant player in California for self-funded employers. In that scenario, large employers have the financial resources to pay their own medical claims. They hire an insurer to administer the health plan and create a provider network.

Anthem had a 37 percent share of the 6.4 million Californians covered by the self-funded market in 2014, according to data from the California Health Care Foundation. Cigna Corp. was second with 24 percent market share, followed by UnitedHealth and Blue Shield of California at 13 percent apiece. (California Healthline is an editorially independent service of the California Health Care Foundation.)

HMO giant Kaiser Permanente has a smaller presence in the state’s self-funded market. In the fully insured market for large employers, Kaiser Permanente leads the state with a nearly 50 percent share.

Under the new deal, the insurer will establish an office in the San Francisco area for OptumLabs. UnitedHealth founded OptumLabs, a collaborative research center, with the Mayo Clinic in 2013 and the headquarters is in Cambridge, Mass. Other partners such as AARP, Harvard Medical School and Pfizer later joined the research effort.

OptumLabs said it will provide UC researchers and physicians access to one of the nation’s largest databases of medical claims, although it will not be publicly available and patients’ identities will not be revealed. It contains claims information on more than 150 million people going back two decades. It also includes electronic medical records on another 50 million patients.

In one research project, OptumLabs has examined whether scanning the narrative portion of electronic medical records could indicate which patients are at risk of developing Alzheimer’s disease rather than waiting for physician tests down the road.

“There is so much depth of knowledge in the University of California system and we are certain when some of that expertise is applied to the data at OptumLabs it will really move us forward,” said Dr. Paul Bleicher, chief executive officer of OptumLabs. “We work on the most difficult problems in health care.”

The two organizations also want to use the California office of OptumLabs to lure young data scientists into the medical field rather than lose them to game developers or social media in Silicon Valley.

“Everybody is struggling with the fact that Facebook, Google and other tech companies are very attractive and obvious targets for new graduates coming out,” Bleicher said. “This will help bring in UC students to work on our data.”

This story was produced by Kaiser Health News, which publishes California Healthline, an editorially independent service of the California Health Care Foundation.