The new study is based on the experience of two hospitals -- Brigham and Women's and Massachusetts General -- that form Partners HealthCare, a not-for-profit healthcare system in Boston. The findings are at odds with another recent study.

In the year 2000, the two hospitals established a health information exchange to access each others' electronic medical records.

"We found that the number of lab tests went down after the introduction if there were recent lab tests available," said Dr. Alexander Turchin, one of the study's authors and an assistant professor of medicine at the Harvard Medical School in Boston.

Turchin and his colleagues looked at 117,606 people who were outpatients at one of the hospitals between January 1, 1999 and December 31, 2004.

Of those, 346 had recent tests done at the other hospital -- 44 patients had them done before the information exchange was rolled out. As for those who did not have recent test results available, 21,968 were at one of the hospitals before the exchange.

Turchin told Reuters Health that the number of lab tests ordered for each patient before the exchange in 1999 was about seven. That number fell to about four in 2004.

For patients without prior tests, the amount slightly increased to roughly six tests per patient from about five.

Compared to the slight increase for patients without tests, the number of tests ordered for those with previous results decreased by 49 percent after the exchange was established. After accounting for confounders -- such as age, sex, the year and number of the tests -- the number of tests ordered fell by about 53 percent.

The new study's results don't jibe with some past research, however.

CONTRADICTING ANOTHER STUDY

Findings published earlier this month in the journal Health Affairs suggested office-based physicians with electronic access to imaging and lab results do not decrease the number of tests ordered. In fact, they may increase it.

"We studied a different population. The question is the same, the population is very different," said Dr. Danny McCormick, the author of the Health Affairs study and an assistant professor at Harvard Medical School.

He told Reuters Health that the new study is consistent with other past research and looks at the Partners' exchange system -- which he called cutting-edge -- whereas his study looked at what is currently happening in doctors' offices across the U.S.

The studies were carried out differently too. And as Turchin pointed out, his study did not include imaging results like McCormick's.

According to Turchin, imaging results may be more susceptible to being reordered by doctors, because the pictures need to be read by a human.

"People may think my radiologists are better than the radiologists next door. So they may repeat the tests," he said. Also, the doctors may misunderstand the results and want to talk to the radiologist.

The team's next step is to look at the potential savings from ordering fewer tests.

But Turchin said that the benefits go beyond money.

"In a broader sense there is comfort for the patient," he said, adding that fewer tests mean fewer blood draws and injections.

McCormick said he believes it's possible to decrease the number of tests nationwide if these kinds of results are extended to every practice.

But, he warns, "It's potentially a big stretch to think you can get this optimization adopted nationwide."

SOURCE: bit.ly/GXxLGi Archives of Internal Medicine, online March 26, 2012.

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