A new study by the Mayo Clinic adds heft to a growing school of thought about reducing health-care costs -- that patients seek less unnecessary care when their own money is at stake.

In this case, as long as there's an incentive in place to see the family doctor first, people make it a habit of putting off what Mayo calls "potentially unneeded services" such as imaging, laboratory tests and outpatient procedures.

"One of the important elements is how do you get the individual patient to buy in?" said lead researcher Nilay D. Shah, an assistant professor of health services research at the Mayo Clinic. "The results showed that with a relatively small amount of cost sharing, individual patients start thinking about the costs."

For the study, published Monday in the journal Health Affairs, Mayo used its own health insurance plan to study how its employees and their families sought out care after it made a change to its benefits in 2004 and shifted more costs to workers.

Prior to 2004, employees with the most generous plans didn't have to pay anything if they wanted to see a cardiologist or orthopedist, or if they wanted to get an MRI or CT scan.

Starting in 2004, Mayo employees had to kick in a $25 copayment to see a specialist, and pay 10 to 20 percent of the cost of diagnostic test.

Mayo researchers, who analyzed data from 2002 to 2007 for employees in Rochester, expected to see a drop in usage of specialists in the early years. What was unknown and not well tested, Shah said, was whether they'd get used to the new costs and revert to old ways.

But the study found that even modest levels of copayments "had an important and sustained effect on health care uses." Patients were more apt to take a wait-and-see approach, rather than seeking out an expensive diagnostic test or going to a specialist, according to the study.

Researchers also worried that patients might pull back on visits to their family doctor or go without preventive screening, such as mammograms and colorectal screenings, thinking that they had to pay for them, even though they were free. But that didn't happen, either.

Shah said that data from hospitalizations didn't show that patients were putting off care but then showing up in the emergency room with bigger health problems.

Dave Delahanty of Towers Watson, a health-care benefits consultant, said patients also are making different choices at the drugstore because they're likely to pay a percentage of the cost rather than a flat copay.

"They're saying, 'Is there a generic available?' or 'Could I double the dose and split the pills?'" Delahanty said. "If they had to pay a flat $10 they wouldn't be asking those questions."

Granted, Mayo Clinic has a more generous health plan than many employers offer. And because its doctors are salaried, they don't get rewarded for running more tests or scheduling more appointments, at least with patients who have private insurance.

But the research offers insight into key elements of health-care reform, which call for providers to become more accountable for keeping people healthy and for primary care doctors to serve as a home base for patient care.

"The goal was to incentivize the primary care provider and have them manage care, through discussions with the patient, rather than the patient going directly out to services," Shah said.

The study did not address high-deductible plans, where people have to pay thousands of dollars out of pocket before their health insurance kicks in.

Jackie Crosby • 612-673-7335