ALBANY — Inc. Magazine on Wednesday named Senior Whole Health the No. 1 fastest-growing private company in the United States, in part because of the company’s growth in the Capital Region.

SWH manages health care for low-income seniors qualified for both Medicare and Medicaid, so called “dual-eligibles,” a niche that has helped the Cambridge Mass.-based company expand revenues from $465,000 in 2004 to $147 million in 2008. The company’s revenue growth over the four-year period was 31,000 percent, according to Inc.’s annual list of the country’s 500 fastest-growing companies.

SWH President and CEO John W. Baackes said his company has gained contracts to receive funding from the federal government and the Medicaid Departments of New York state, Connecticut and Massachusetts and owns separate wholly owned subsidiaries that do business in each state.

“We opened New York in January of 2007, so it helped push us over the top. The company that was next on the [Inc Magazine top 500] had growth of 24,000 percent,” Baackes said.

SWH’s Albany subsidiary employs 37 people and serves 610 customers in Albany, Rensselaer, Saratoga, Schenectady, Ulster and Dutchess counties.

Meg Wallingford, executive director of SWH’s Albany subsidiary, said SWH is expanding throughout the Capital Region using a “grass-roots approach.” She said she expects the company to sign an additional 30 to 50 customers this month.

Baackes said seniors who choose SWH retain all of their entitlement rights under Medicare and Medicaid and gain access to an SWH card, replacing their Medicare, Medicaid and Medicaid Part D identification cards. They also get an around-the-clock health care team that includes a registered nurse care manager and a community support specialist.

He said the federal and state governments SWH contracts with pay the firm a set monthly estimate based on how much the customer would likely charge to Medicare and Medicaid.

“[The Medicare and Medicaid systems are] gambling that we will be able to do a better job at managing the care because they can’t afford to put a nurse-care manager in place and that we will ultimately provide [customers] with a level of care that will keep them out of an institutional setting, which is primarily nursing homes and repeat visits to hospitals, which [Medicaid and Medicare] would have to pay a lot more for,” Baackes explained.

Under its agreements with Medicare and Medicaid, SWH retains liability for the costs of customers who exceed the monthly estimates each system pays to SWH. Baackes said SWH’s business model is similar to the insurance industry, in that a risk pool of customers is created to cover the costs of customers that exceed the monthly estimates. He said SWH has 5,000 customers in Massachusetts and 500 in Connecticut and will need to increase the risk pools to about 1,500 customers in both New York and Connecticut over the next two years to meet the company’s projections of a sustainable business model.

Wallingford said SWH has been able to save the Medicare and Medicaid systems money by discovering some customers who had redundant prescriptions with multiple doctors and other instances where professional guidance could reduce costs without reducing quality of care.

Farther down on Inc’s list of fast growing company’s was Schenectady-based Transfinder Corp., which made its second consecutive appearance on the list as the 3,790th fastest growing private company after 80.9 percent year-over-year annual growth.