Efforts to hold down medical bills are showing some signs of success.

Researchers in the consulting arm of Aon Corp., Chicago, have published figures supporting that conclusion in a summary of results from an informal survey of 90 large health insurers.

The survey suggests that, excluding the cost of prescription drug benefits, underlying health care cost trends will increase 11.4% for preferred provider organization plans in 2007, down from 12.8% from the 2006 forecast made a year ago, the researchers report.

Cost trends for plans that incorporate health savings accounts or health reimbursement arrangements are set to increase 10.3%, down from 13.2%, the researchers estimate.

General pharmacy cost inflation should fall to 10.6%, from 11.8%, the researchers report.

The rate of increase for dental preferred provider organization coverage has fallen to 6.5%, from 7.1%.

The increases are still extremely high, but they suggests that efforts to control price increases, increase patients’ out-of-pocket costs, promote wellness and improve management of chronic conditions are paying off, the researchers assert.