UnitedHealth Group is expanding a program with Mayo Clinic that encourages patients across the country to travel to the Rochester-based health system for certain specialized procedures.

For more than 10 years, Mayo Clinic has been designated by the Minnetonka-based insurer as a "center of excellence" for organ transplants, which means health plans offer incentives if patients travel to Rochester for care.

Under an agreement being announced Wednesday, the program will expand to include cancer, bariatric surgery, heart failure, congenital heart disease and infertility services.

Insurers say such programs save money because patients experience fewer complications at top-quality hospitals, which also offer discounts for procedures. For Mayo Clinic, this is the third collaboration in as many years with Optum, a UnitedHealth Group subsidiary in Eden Prairie that sells IT and health services.

"Our feeling is that the major cost savings, and the major benefit to the patient, is having an experienced team that arrives at the right diagnosis," said Dr. Charles Rosen, the medical director for contracting and payer relations at Mayo Clinic. "Whenever you treat a condition that's ­misdiagnosed, it's not only potentially harmful to the patient — and delays treatment of the primary problem — but it costs a lot of money."

Neither the clinic nor Optum released projections for how many patients might come to Mayo's campus in Rochester, or to hospitals in Arizona and Florida, as a result of the agreement. Nor did they release financial terms.

But the deal fits with a continuing theme at Mayo Clinic, which tries to distinguish itself as a destination for patients with complex medical needs. Currently, about 30 percent of patients treated at Mayo Clinic in Rochester travel at least 120 miles for the care.

"It's a very large portion of our practice," Rosen said.

The centers of excellence program is run by Optum, which provides the service both for UnitedHealthcare insurance customers, as well as other health insurers who pay to use the network. The number of designated centers varies by condition. The insurer's network for organ transplants included 153 centers, while there were 18 centers in congenital heart surgery, a UnitedHealthcare official said in an interview this spring.

Employers that elect to incorporate centers of excellence into their health ­benefits have options in how they can structure employee incentives. In some cases, an employer might cover transportation costs if workers have to travel to one of the centers, said John DeSmet, senior vice president of ­network solutions at Optum.

Per diem caps for lodging and meals go up to $200, and transportation benefits typically apply when people must travel 50 or more miles. Overall reimbursement commonly is capped at $10,000.

Most patients live within 100 miles of a designated center, Optum says. Other incentives can be structured so employees have lower out-of-pocket costs if they obtain care at a preferred hospital.

"Thirty million people have access to our centers of excellence program," DeSmet said. "With a brand name like Mayo, there would be a great attraction for patients."

For all the health conditions being addressed by Wednesday's announcement, Mayo Clinic will join several other health care providers across the country that already are designated as ­centers of excellence. Like Mayo, some of these hospitals have been designated as high-value centers for treatment of multiple conditions.

Optum has operated ­centers of excellence programs for many years, but officials say there's been an uptick in interest recently. With transplants, Optum says the program has helped lower the average length of stay for hospital patients, while helping avoid unnecessary and inappropriate transplants.

"I think employers are looking at ways to impact quality and cost, and they're trying to find creative ­solutions to achieve both objectives," DeSmet said.

There are other signs of growth.

When Minnetonka-based Medica announced plans this year to expand in Iowa and Nebraska, it said it would develop a centers of excellence program so patients with specialized health needs could travel to the Mayo Clinic.

Last year, retail giant Wal-Mart announced a centers of excellence program that directs employees to Mayo Clinic for cancer care.

In 2013, the Pacific Business Group on Health in San Francisco started programs for ­several national employers to send joint replacement patients to a select group of medical centers. This year, the group planned to launch another ­program in spine surgery.

The program expansion being announced Wednesday is the third major ­initiative between Mayo Clinic and Optum.

In 2013, the groups jointly started OptumLabs, a research project to improve medical care and lower treatment costs by exploiting the growing mass of electronic health data. Currently, OptumLabs has 22 partners, including Harvard Medical School, pharmaceutical giant Merck and the University of Maryland in Baltimore.

Earlier this year, Mayo Clinic announced its partnership with Optum360 on a ­system for giving patients price estimates before receiving care, and for collecting medical bills afterward.

Christopher Snowbeck • 612-673-4744

Twitter: @chrissnowbeck