Employers that offer optional health savings accounts and health reimbursement arrangements may avoid a total of about $500 in claims per member over 4 years.

Researchers at Aetna Inc., Hartford, have come up with that estimate in an analysis of 5 years of data from 130 employer health account programs with a total of about 205,000 participants.

The results include data for 170,000 HRA users and 35,000 HSA users.

All of the users are under age 65, and the their demographics are comparable to those of other Aetna preferred provider organization plan members, Aetna says.

In most cases, the savings figures represent amounts cut from anticipated spending increases, rather than decreases in spending relative to the employers’ initial health coverage costs.

Health account savings average about $8 in savings on anticipated costs per member per month in the first year, $10 per member per month in the second year, and $12 per member per month in years 3 and 4.

About 5% of the HSA holders and 48% of the HRA holders use all of their account assets in a given year, and about 40% of the HSA holders and 18% of the HRA holders use none of the accounts estimates, the Aetna researchers found.

At employers that replaced all health coverage with HRA programs, savings averaged about $2,100 per member over 4 years, but the savings dropped from $59 per member per month in the first year to $27 per member per month in the fourth year.

At the HRA option programs that Aetna regards as very well run health account programs, the average savings increased from $18 per member per month in the first plan year to $47 per member per month in the fourth plan year.

Overall, health account plan members spent about 20% more than typical PPO members on preventive care and 15% less on emergency room use, Aetna says.