A major form of funding for community health centers is set to expire at the end of the year. A wide coalition of groups including Advocates for Community Health, which represents health centers, is pushing for an extension of at least three years with a minimum of $5.8 billion a year. Earlier this year, Congress passed a spending package that extended funding for the centers at an annualized rate of $4.27 billion — up $270 million from the previous year.