By STEVE LeBLANC
Associated Press

BOSTON - Workers who better understand their health-insurance plans - from their share of premiums to co-payments for doctor office and emergency-room visits - are more likely to make more cost-efficient decisions, a new study finds.

The study, which surveyed about 1,500 government workers in Massachusetts, found that nearly two-thirds could recall the percentage of the premium they paid, and slightly more, 67 percent, remembered their co-payment for a visit to the doctor's office.

Just more than half, 55 percent, recalled what their co-payment was for a visit to the emergency room. Of those who incorrectly reported their emergency-room co-payment, about a third overstated the amount by $25 or more.

Researchers merged the survey findings with claims data for respondents and their dependents. The survey was conducted in June and July of 2005 by researchers at Tufts University School of Medicine and Boston University School of Public Health.

Those who knew their co-payments were more likely to have more office visits and fewer emergency-room visits, which are typically more costly, according to the study.

"If people are more aware of their overall health-care costs and how the different types of care have different costs, then people will use the health-care system more efficiently," said Amy Lischko, the lead author of the report and former commissioner of the Massachusetts Division of Health Care Finance and Policy.

Lischko said the study suggests that just raising co-payments alone doesn't necessarily encourage employees to seek doctor's-office visits, which are typically less expensive than emergency or immediate care. She said employers have to work harder to educate workers.

That education will become even more important as the new federal health-care overhaul law comes into effect over the next few years and people who have never had insurance have to learn when to go to the emergency room and when to schedule a doctor's visit, she said.

"We have to do a better job at educating the newly insured about what it means to be insured," Lischko said. "It's going to be very complicated for people used to showing up at the emergency room whenever they have a need."

The report was published in The American Journal of Managed Care.

Researchers said one drawback of the study was that it was limited to people with government jobs, who may not be representative of the employed population of the nation as a whole.

At a hearing on health-care costs last month, Massachusetts Attorney General Martha Coakley released a study that found prices paid by health insurers to hospitals vary widely within the same geographic area and cannot be explained by the quality of care.

She said most of the increase in health spending in the state is because of the higher costs those hospitals charge for services, not an increase in the number of services.