Group health care plan costs rose 5.5% in 2009, the lowest increase in more than a decade, as employers stepped up cost-control efforts, according to a survey.

That 5.5% increase brought costs to an average of $8,945 per employee this year compared with $8,432 last year, according to a survey of nearly 3,000 employers released last week by Mercer L.L.C. in New York.

Costs rose an average 6.3% in 2008; from 2005 through 2007, costs increased an average of 6.1% each year. Health care cost increases peaked in 2002 when they jumped 14.7%, with lesser increases since then, according to the consulting firm.

“This is good news and the cost increase is a better number than we might have expected,” said Linda Havlin, a Mercer worldwide partner in Chicago. Use of health care services often spikes in recessions as employees, fearful of losing their jobs and coverage, seek more care, she said.

One factor limiting cost increases, especially among smaller employers, was increased adoption of consumer-driven, account-based health care plans that have significantly lower costs than more traditional plans.

For example, 15% of employers with between 10 and 499 employees in this year's survey offered a CDHP linked to either a health savings account or health reimbursement arrangement, up from 9% last year. Of those offering a CDHP, it is the only medical care plan that 55% provide to employees.

The difference in costs between CDHPs and other plan designs is striking. CDHPs linked to HSAs cost an average of $6,393 per employee in 2009, nearly $2,000 less per employee than preferred-provider organization or point-of-service plans, according to the survey.

Eighteen percent of smaller employers said it is “very likely” they will offer a CDHP next year, while 24% of larger employers—those with at least 500 employees—said it is very likely they will offer a CDHP in 2010. This year, 20% of larger employers offer a CDHP.

Along with increased employer adoption of CDHPs, employee enrollment, while still small, also is rising. In 2009, 9% of employees were enrolled in CDHPs linked to HSAs or HRAs. As recently as 2006, just 3% of employees were enrolled in CDHPs.

Another important factor helping keep costs more controlled is increased employer adoption of health management programs, such as health risk assessment programs that seek to identify employees' health conditions so action can be taken to prevent those problems from worsening.

For example, 73% of employers with at least 500 employees said they offered a health risk assessment program this year, up from 65% last year; 71% offered a disease management program this year, up from 66% last year.

Ms. Havlin says there is much more that can be done to better manage care for employees who generate a majority of health care costs.

Slowing rises in group health care plan costs also resulted from a longtime employer strategy: shifting more costs to plan participants. For example, among PPOs in which a deductible is imposed for in-network coverage, the average individual deductible climbed to $1,096 this year, up from $1,001 last year. As recently as 2004, the average PPO deductible for individual coverage was $686.

Other survey findings include:

c The percentage of employers offering health care coverage remained steady at 65% in 2009, unchanged from the prior year but down from 70% in 2001.

c Forty-seven percent of employers either have or will have to revamp mental health care benefits to comply with federal requirements that generally go into effect on Jan. 1. Those requirements, embedded in a broader bill Congress passed last year, require group health care plans to provide the same coverage for mental disorders as they do for other medical conditions.

c Employees on average contribute $1,424 a year to their health care flexible spending accounts. That is well below a $2,500 cap included in a health care reform bill passed by the House of Representatives and another measure now awaiting action by the full Senate.

c Twenty-three percent of employers with at least 20,000 employees discount health insurance premiums for nonsmokers, up from 17% in 2008.

The report, “National Survey of Employer-Sponsored Health Plans,” will be published in March. The report costs $600 and the report and tables cost $1,200. More information is available at www.Mercer.com/ushealthplansurvey or from Tara Lewis at 212-345-2451.