Enrollment in high-deductible health plans rose 5.2% over the last two years, according to government estimates.

A “significant increase” was evident in the number of people enrolled in HDHPs without Health Savings Accounts and in consumer-directed health plans (CDHPs) between 2007 and June 2009, according to the estimates from the U.S. Centers for Disease Control and Preventions National Center of Health Statistics. The estimates are based on interviews with more than 32,000 people.

These plans can provide employers and employees with cost savings over traditional plans, but have been slow to be adopted because of a lack of understanding, according to industry experts.

In the first six months of the year, 22.7% of people under age 65 with private health insurance enrolled in HDHPs. In 2007, 17.5% of people enrolled in HDHPs,

Of those enrolled in HDHPs, 6.4% who were enrolled in a consumer-directed health plan.

Researchers found that almost half of people enrolled in private plan not provided by their employers were in a HDHP. An estimated 20.2% of persons with a private plan were in a family with a flexible spending account (FSA) for medical expenses, an increase from the 16.7% estimated in 2007.

Based on data from the first six months of 2009, among persons under age 65 with private health insurance, 20.3% with employer-based coverage were enrolled in a HDHP, compared with 48.7% of those with a private plan that was directly purchased or obtained through means other than an employer.

The percentage of persons covered by employer-based private HDHPs increased from 15.6% in 2007 to 20.3% in the first 6 months of 2009.

The percentage of persons covered by directly purchased private health plans that are HDHPs increased from 39.2% in 2007 to 48.7% in the first 6 months of 2009. HDHPs constitute a growing share of both employment-based and directly purchased health plans, researchers said.

About 8% of private health plans are directly purchased for persons under age 65.