In an unusual move that reflects the national clamor for health care reform, two of the Twin Cities' biggest medical groups will collaborate in a seven-year effort to slow the rise of medical costs in the northwest suburbs.

HealthPartners and Allina Hospitals and Clinics said Tuesday that they plan to try out new payment formulas to reward quality and improve patient satisfaction, ultimately producing lower costs in that area compared with the rest of the metro.

The HealthPartners clinics are in Coon Rapids, Andover, Anoka and Elk River. Allina in turn brings Mercy Hospital and its clinics in Champlin, Coon Rapids, Elk River and Ramsey.

Some 170,000 patients will be affected.

"We will continue to be separate organizations but will bring the assets of two organizations together to work more effectively on quality improvement," HealthPartners Chief Executive Mary Brainerd said.

Allina is the Twin Cities' biggest clinic and hospital group. HealthPartners is the state's third-biggest health insurer and also has a chain of clinics.

They picked the northwest suburbs because both have strong primary care clinic networks in the area.

Many details remain sketchy, including which outcomes will be measured for payment purposes. Nor are they saying what level of savings would constitute success.

Fairview Health Services and Medica announced a similar payment experiment in July in which Medica, the insurer, would pay more for healthy outcomes at Fairview clinics and hospitals.

The Allina/HealthPartners effort is a little different. Because HealthPartners is both an insurer and a medical group, the effort will essentially ask two medical groups to put aside their rivalry and think as one -- at least in that one geographic area.

Among other things, they have agreed to share electronic medical records and high-end equipment such as diagnostic imaging machines.

"The number one issue is how expensive health care is," Brainerd said. "We're motivated to look at these options differently than we would have five years ago."

Chen May Yee • 612-673-7434