New York City's Health and Hospitals Corp., which operates the biggest municipal health system in the U.S., said its budget deficit will more than triple to $1.4 billion in four years. The system, which served 1.4 million patients last year, including 500,000 without health insurance, is suffering from Medicaid reimbursement cuts and "astronomical increases" in pension and employee health-insurance costs, Alan Aviles, president of the agency, said today in written testimony for the city council health committee. "The safety-net role of our public hospital system has made HHC especially vulnerable to deep cuts to Medicaid, the cost of serving a rising tide of uninsured patients and the erosion of federal funding," Aviles said.