14 Dec ED patients more confident in diagnosis based on CT

AuntMinnie.com | December 14 – Emergency department (ED) patients with abdominal pain are far more confident in their diagnosis when a CT scan is used as part of their workup, according to a study in Annals of Emergency Medicine. However, the patients knew surprisingly little about the risks of ionizing radiation, the authors wrote.

“Patients with abdominal pain are four times more confident in an exam that includes imaging than in an exam that has no testing,” said lead author Brigitte Baumann, MD, from the University of Medicine and Dentistry of New Jersey, in a statement accompanying release of the study. “Most of the patients in our study had little understanding of the amount of radiation delivered by one CT scan, never mind several over the course of a lifetime. Many of the patients did not recall earlier CT scans, even though they were listed in electronic medical records.”

The study, conducted from March 2008 to May 2009 at an emergency department in an urban, tertiary referral hospital, surveyed 1,168 patients with nontraumatic abdominal pain who presented to the emergency room.

“The recruitment of abdominal pain patients enabled us to capture a sample of patients whose presenting chief complaints would lead to a broad range of medical and diagnostic evaluations,” wrote Baumann, along with colleagues including Esther Chen, MD, and Angela Mills, MD, from Camden, NJ; the University of California, San Francisco (UCSF); and the University of Pennsylvania in Philadelphia (Annals of Emergency Medicine, December 18, 2010).

The study included results for 1,168 patients who presented with nontraumatic abdominal pain lasting 72 hours or less. According to results, 20% reported confidence in a medical evaluation that included patient history and physical exam only, while 90% reported confidence in a medical evaluation that included patient history, physical exam, blood work, and a CT scan.

However, 75% of patients underestimated the amount of radiation delivered by a CT scan, and only 3% understood that CT scans increase a person’s lifetime risk of cancer, the researchers wrote. Some estimates hold that 1.5% to 2% of all cancers in the U.S. may be attributable to the radiation from CT exams.

Another problem was that patients had no recollection of previous CT scans, Baumann and colleagues wrote, which could complicate efforts to reduce unnecessary exposure to medical radiation. At the same time, patients’ lack of awareness about how many CT scans they had previously received wasn’t associated with a lack of scans. Medical records of previous CT scans ranged from one to 57 per patient — and one to 33 in the subset of patients with no history of cancer.

The number of scans during the previous five years (mean, 5.4) was also higher than that found in another recent study, the authors wrote. Extrapolating the results of the other study to the current cohort, 53% of patients would have had more than five CT scans, 15% would have had more than 22, and 3% would have had more than 32 scans during a 22-year period, the authors wrote.

“Irrespective of whether CT rates were to level off or continue to increase, our data suggest a high use of previous CT imaging in our abdominal pain patient population,” Baumann and colleagues wrote.

Going forward, patient expectations in the emergency department are expected to be a considerable challenge. Using four medical scenarios to assess patient confidence, the study found that patients with abdominal pain expect some type of laboratory or radiologic testing, as evidenced by the great differences in diagnostic confidence between imaging patients and nonimaging patients.

“As great a diagnostic tool as CT is, we need to do a better job of educating our patients about the risks associated with CT scans,” the authors said.

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