Annadel Medical Group, whose physicians are affiliated with Santa Rosa Memorial Hospital, has joined forces with the Marin-Sonoma IPA, an independent physicians' network that is quickly expanding into the North Coast from its base of Marin County and southern Sonoma County.

Annadel, which has 28 physicians and five nurse practitioners, provides medical services to patients at various facilities operated by St. Joseph Health System-Sonoma County, including Santa Rosa Memorial Hospital and Petaluma Valley Hospital.

Annadel is expected to announce its participation in the Marin-Sonoma IPA network this afternoon, but Joel Criste, the IPA's CEO confirmed the deal, which he said follows several other new agreements with physicians in Santa Rosa and Healdsburg.

HMO patients whose doctors are part of the IPA will be able to "access care in a network from Sausalito to Healdsburg," he said.

Participation in the IPA means that Annadel doctors will accept HMO patients who are enrolled in the Marin-Sonoma IPA, he said. The IPA will take over the task of negotiating contracts with HMO plans, securing a prepaid contract for physician services.

"It's about attracting patients and providing better services," Criste said.

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