Physicians ordering unnecessary DI
tests, study says
TORONTO – Doctors often seem to
prescribe CT and MRI scans when they are of little or no medical use,
according to a story in the National Post newspaper. The phenomenon
perhaps explains why Canadians still experience substantial delays to
get the tests.
Large percentages of the scans reviewed by the researchers either
unearthed no medical problems, or detected abnormalities that would not
change how the patient was treated, raising questions about whether they
should have been ordered in the first place.
According to the study authors, physicians need more education about use
of the medical imaging tools, along with access to a new generation of
computer programs that can advise them which test, if any, is the best
for given patients.
“We need to bring things into better balance,” said Dr. John You, the
internal-medicine specialist who led the research for the Institute for
Clinical Evaluative Sciences.
“There are people out there for whom CTs and MRIs are probably crucial
for their care and they’re probably waiting too long. There’s other
people who are getting the scans and probably didn’t need to.”
But Dr. David Vickar, president of the Canadian Association of
Radiologists (CAR), said that the results should be viewed cautiously.
Because most CT scans for headache sufferers found nothing, for
instance, does not mean that most of them should not have been done, he
Still, he acknowledged that as many as 20 percent of scans are ordered
needlessly. “We could be doing a better job of requesting appropriate
exams,” said Dr. Vickar.
The numbers of both CT scans and magnetic resonance imaging (MRI) tests
performed in Canada has soared in recent years. In Ontario, for
instance, the number of CT scans jumped three fold and the number of
MRIs six fold between 1993 and 2003.
But wait times for the tests, considered an invaluable tool for
diagnosing certain diseases and injuries, have not come down
appreciably, said Dr. You. An Ontario Health Ministry official said
yesterday that queues did decrease in the last year – by 16% for MRIs
and 42% for CT scans.
The Fraser Institute, a conservative think tank, offers a less rosy view
in its annual survey of physicians on healthcare delays, recording
barely any change in wait times for the tests in Ontario last year.
Dr. You’s study scrutinized more than 22,000 outpatient CT and MRI scans
carried out at Ontario hospitals on or after Jan. 1, 2005. Most
strikingly, it found that headaches were the most common reason why
doctors ordered CT scans of the brain, yet less than 2% of the tests
revealed any treatable illness.
MRI scans of the spine were most often prescribed because the patient
complained of back pain. While 90% found some kind of abnormality, it
usually had nothing to do with the pain, or would not lead to any
different treatment, said Dr. You.
One consequence of doing such tests is that they can lead to a “cascade”
of other diagnostic procedures, he said. The result of one in four
abdominal CT scans reviewed by the study, for instance, was a
recommendation for more testing.
Both Dr. You and Dr. Vickar recommended wider use of computer programs
that, using CAR guidelines, allow doctors to input their patient’s
symptoms, and get back advice on which diagnostic test to order.
The Winnipeg children’s hospital is about to publish results from a
pilot project it conducted with such software.