Rising insurance premiums are helping to push U.S. health care spending higher. According to the Health Care Financing Agency, total spending increased 5.6 percent in 1998, up from 1997's 4.7-percent rise. Various benefit-consulting firms concur that, for the first time in several years, many employers face double-digit premium increases. In addition, an International Society of Certified Employee Benefit Specialists study found that the top concern of corporate benefit managers this year is health care costs.