Western Health Advantage formally announced its plan to expand into the North Bay, adding Marin, Sonoma and Napa counties to its roster with hopes of offering a commercial health plan for employers and individuals by Jan. 1.

In June, the Sacramento-based HMO (916-563-2250, westernhealth.com) filed expansion plans with the state Department of Managed Health Care. [See "HMO plans to expand into North Bay," Aug. 20.] The initial filing only listed Sonoma and Marin counties, but it was later amended to include Napa County. The geographic expansion is still pending approval by the state.

"Western Health Advantage is pleased to work with an emerging regional network of well-respected local institutions to bring our services to a new geographic area," Garry Maisel, president and chief executive officer, said in a statement.  "This expansion furthers our mission to improve the health and well-being of the areas we serve by responding to the changing needs of our members, providers and community."

Western Health Advantage is partnering with the following provider and hospital networks: Meritage Medical Network, formerly known as the Marin-Sonoma IPA; Healdsburg District Hospital; Palm Drive Hospital in Sebastopol; Sonoma Valley Hospital; Marin General Hospital in Greenbrae; and St. Joseph Health--operated facilities Santa Rosa Memorial Hospital, Petaluma Valley Hospital and Queen of the Valley Medical Center in Napa.

The Meritage Medial Network, itself seeking an expansion to Napa, currently contracts with about 100 specialists and 20 primary care physicians in Napa County, according to Marcy Norenius , director of special projects. If and when Western Health Advantage gets approval for the expansion, the physician network would seek to add those physicians, bringing its total membership to a little more than 700.

"Western Health Advantage has demonstrated a commitment to quality and financial transparency to our medical network that we believe will be attractive to local employers and individuals," said Joel Criste, CEO of Meritage Medical Network.

Jon Friedenberg, chief fund and business development officer for Marin General, said the prospect of having another product could be an attractive alternative for employers in the North Bay.

"We think it's a product that some consumers are going to be very attracted to, so we thought it was important to be among the providers that consumers who choose that product can use for their health care needs," Mr. Friedenberg said. "In some markets, this type of product does very well. I wouldn't be surprised if there are a meaningful number of consumers who sign up."

If approved, the move into three more North Bay counties would give Western Health Advantage a continuous foothold from Marin County to Sacramento. Currently, Western Health Advantage operates in Solano, Yolo, Sacramento, Placer and El Dorado counties and serves some 92,000 members. The not-for-profit HMO was founded by the UC Davis Health System, Fairfield-based NorthBay Healthcare and Mercy Healthcare/Dignity Health.

Details of how many new members would be added in the three North Bay counties are not yet clear. The initial filing that listed Marin and Sonoma counties conservatively estimated about 3,900 new members in the first year of operation, focused primarily on employer groups. With Napa County in the mix, that number would increase.

Numerous proponents in the North Bay have cited the HMO's ability to compete with Kaiser Premanante in the Sacramento and Solano regions as an attractive alternative for both North Bay providers and employers, particularly Sonoma County's district hospitals, which have struggled to maintain their share of insured patients because of competition from health care heavyweights Kaiser and Sutter Health.

Rick Heron, a spokesman for Western Health, previously told the Business Journal that the expansion into the North Bay is part of the HMO's adaptation to health care reform.

The individual market could also be in play, with the California Health Benefit Exchange set to launch in 2014. Small employers and individuals will be able to purchase insurance plans through the exchange.

Western Health Advantage's expansion could also help fill a void created when Santa Rosa-based Health Plan of the Redwoods shuttered in 2002, a gap Kaiser quickly filled. Kaiser's San Rafael Medical Center, which includes Petaluma, has 120,258 insured members, while it's Santa Rosa Medical Center has 141,338 members. The next-largest HMOs serving the North Bay are Blue Shield with 15,000 members, Health Net with 12,000 and United Healthcare with 4,200.

Western Health Advantage's network currently includes more than 500 primary care providers, 1,800 specialists and eight hospitals in the Sacramento-Solano region.