The growth rate of health care spending continues to remain low, a new report says, but consumers may not be getting much of a relief.

Health spending by privately insured patients increased 4 percent last year, according to the Health Care Cost Institute, continuing a three-year trend of lower health spending growth. But consumers are spending more on out-of-pocket costs, and women and young adults are now carrying a bigger burden.

Health care spending averaged $4,701 per person with employer-sponsored coverage in 2012, up $181 from the year before, the nonprofit group that conducts health research found. Almost half (45 percent) of the additional dollars were due to more spending on outpatient care. Out-of-pocket spending rose more quickly than expenditures per person in 2012, increasing 4.8 percent to $768 for each individual, the report found.

The study analyzed data from 156 million U.S. residents younger than age 65 who have employer-sponsored health coverage, focusing on medical bills submitted to Aetna, Humana and UnitedHealthcare from 2009 to 2012.

“Although average health care expenditures grew at nearly the same rate in 2012 as 2011, the causes of the 4 percent increase in spending each year were quite different,” said David Newman, executive director of the insurance industry-backed institute.

While price increases drove overall spending increases in years prior, utilization changes in 2012 impacted spending on prescription drugs and professional procedures, with more patients searching for low-cost care alternatives, Newman said.

Meanwhile, overall spending grew fastest for young adults, women and people living in the Northwest.

Women's out-of-pocket costs were more than $200 greater than men's out-of-pocket costs, $883 per capita for women compared to $647 for men. Those costs have also increased more quickly than for men.

Health care spending rose faster—5.4 percent—for young adults (ages 19-25) than any other age group. By contrast, the oldest adults (ages 55-64) experienced the slowest health care spending growth—2.5 percent. Young adults continued to have some of the lowest expenditures ($2,548 per person) while the oldest adults had the highest ($8,920 per person).

Nearly half (43 percent) of all out-of-pocket dollars were spent on professional procedures, such as doctor visits and lab tests. More than a quarter (26 percent) of consumer dollars were spent on outpatient services, the report found.

For the third year, spending grew fastest for outpatient care compared to the other service categories, rising 6.5 percent to $1,315 per person in 2012. Prices also rose fastest for outpatient care, increasing 5.6 percent. The price of an outpatient visit to an emergency room, for example, averaged $2,457, and the price for other outpatient services, diagnostic imaging, for example, averaged $192.