U.S. employers’ health care costs could grow 9% in 2010, according to PricewaterhouseCoopers L.L.P.

The Health Research Institute unit at PricewaterhouseCoopers, New York, are predicting the rate of growth will be only slightly slower than the growth rate in previous years.

Medical costs grew 9.2% this year and 9.9% in 2008, the institute found.

The institute drew in part on a survey of about 500 employers and many health carriers.

The economic slump may have contributed to continued growth in health costs, the researchers , the institute says. In some case, workers are stepping up use of health care in anticipation of losing their jobs and their health insurance. Rising unemployment also is increasing the number of uninsured and underinsured patients, cutting commercial health plan enrollment, and increasing the percentage of the population covered by Medicaid.

Factors that could hold down medical costs include the possibility of health reform and growth in high-deductible health plans and wellness programs, the institute says. One challenge: Many employers already are offering wellness and disease management programs, but few that participated in the institute survey have found those programs to be very effective at lowering costs.