Citing economic challenges in the region and country, two of Western Washington's largest hospital systems announced a plan to combine forces, creating a new, nonprofit entity that would operate the largest health-care system in the state. The new entity would include Swedish Health Services in Washington, which operates five hospitals and clinics in King, Snohomish and Kittitas counties, and Providence Health & Services operations in King, Snohomish, Thurston and Lewis counties. In those counties, Providence operates three hospitals and 21 senior and community-service programs, including hospice, home health, nursing homes, assisted-living facilities and senior housing. In a conference call this week, the CEOs of Swedish and Providence portrayed the affiliation as one born of economic necessity. Insurance reimbursements are shrinking, and unemployment is persisting, and fragmented, uncoordinated care consumes an ever-larger share of budgets.