In the debate over the high cost of health care, federal policymakers have always claimed that one way to cut costs is for doctors to use electronic medical records and other information technology. Doing so, they say, avoids duplication and saves money.

But new research suggests that may not be the case.

Doctors who have easy computer access to results of X-rays, CT scans and MRIs are 40 to 70 percent more likely to order those kinds of tests than doctors without electronic access, according to a study to be published in the March issue of the journal Health Affairs.

“On average, this is comparing doctors who had electronic medical records and those who didn’t,” said lead author Danny McCormick, a physician and assistant professor of medicine at Harvard Medical School.

Researchers say the findings challenge a key premise of the nation’s multibillion-dollar effort to promote the widespread adoption of health information technology.

“This should give pause to those making the argument,” McCormick said. Instead of saving money, that effort could drive costs higher, he said.

For the study, researchers at the Cambridge Health Alliance, a health system in Cambridge, Mass., and the City University of New York analyzed data from a 2008 federal government survey. The data included information collected from 28,741 patient visits to 1,187 office-based doctors. The information included the type of doctor, their office computerization and the tests ordered at each visit. About half of the doctors’ offices surveyed had computerized access to results of X-rays and other imaging tests.

Researchers found that doctors who did not have computerized access ordered imaging tests in 12.9 percent of visits, while doctors with electronic access ordered imaging in 18 percent of visits, a 40 percent greater likelihood. Doctors with computerized access were even more likely — about 70 percent more likely — to order advanced imaging tests, such as PET scans, which experts said are most commonly used to detect cancer, heart problems, brain disorders and other central nervous system disorders.

The study found the results hold true even after taking into account other factors, such as patient demographics, doctor specialty and physician self-referral.

Researchers were not able to determine why physicians ordered the imaging tests, or whether in those cases, physicians had looked at patients’ prior chest X-rays. Nor were they able to assess whether the increased imaging helped or harmed patients.

The data also didn’t indicate whether a doctor’s computer system had sophisticated features, commonly known as online clinical decision support, that help doctors make treatment decisions.

At some flagship hospitals with customized health information technology systems, for example, doctors get specific feedback about diagnostic tests that can result in ordering fewer tests.

“If you try to order an MRI, [the computer system] tells you that given the patient’s age and what you’re looking for, this test has a 3 percent chance of giving you useful information,” McCormick said.

Most doctors’ offices don’t have the same kind of customized IT support and instead, are using “off-the-shelf” electronic systems, he said.The researchers said no studies have looked at the relationship between technology improvements in typical doctors’ offices and the ordering of imaging tests.

The federal government has rolled out an ambitious plan to modernize health care using electronic health records, providing up to $27 billion in incentives over 10 years to encourage doctors and hospitals to go electronic.

Michael Furukawa, a health economist in the Office of the National Coordinator for Health Information Technology, the administration’s health IT czar, said the researchers’ focus was not deep enough to support the study’s conclusions.

“The data are sound, the methods are appropriate, but the focus is limited,” he said. “They only looked at one piece of health IT.”

Doctors who had better electronic systems, for example, might get alerts recommending against ordering X-rays. If researchers had taken that factor into account, “the results wouldn’t have been as strong,” Furukawa said.

The results might also be different if researchers had distinguished between new patients with acute conditions who might need more X-rays, and those who just had surgery and already had an imaging test, he said.

“The proper use of advanced health IT functions, we believe, will reduce costs in the long run,” Furukawa said.

The study’s authors said one possible reason for the findings could be an unintended consequence of computerized health record systems. They make it easier for doctors to order more imaging studies with a few clicks and keystrokes.

“As with anything, if you make it easier to do, people will do it more often,” McCormick said.

“In borderline situations, substituting a few keystrokes for the sometimes time-consuming task of tracking down results from an imaging facility may tip the balance in favor of ordering a test,” the authors wrote.