High users of CT pulmonary angiograms have lower diagnostic yields

Clinical question: What physician characteristics are associated with CT pulmonary angiogram (CTPA) diagnostic yield?

Background: Overuse of CTPAs for pulmonary embolism evaluation exposes patients to unnecessary testing and harmful ionizing radiation. Physician characteristics influence ordering practice. Identifying specific characteristics can provide an intervention for reducing overutilization.

Study design: Retrospective analysis.

Setting: Academic teaching hospital in Montreal, Canada.

Synopsis: Investigators reviewed 1,394 CTPAs ordered by 182 physicians at an academic teaching hospital during 2014-2016, with 199 (14.3%) positive studies and 1,195 (85.7%) negative studies. Physician years of experience, physician sex, and emergency medicine specialty were not associated with diagnostic yield. However, the diagnostic yield decreased with the total number of scans ordered per physician. For every 10 additional scans ordered, the odds of a positive test were reduced (odds ratio, 0.76; 95% confidence interval, 0.73-0.79). For physicians who ordered more than 50 studies, the percentage of positive studies was only 5%.

This study’s results show that overuse of CTPA is associated with decreased diagnostic yield. A limitation of the study was that pretest probabilities for pulmonary embolism could not be calculated because of inadequate charting, which would have determined whether CTPA was the appropriate test (as opposed to D-dimer).

Bottom line: Physicians who order higher numbers of CTPAs have lower diagnostic yields.

Citation: Chong J et al. Association of lower diagnostic yield with high users of CT pulmonary angiogram. JAMA Intern Med. 2018 Mar 1;178(3):412-3.

Dr. Komsoukaniants is a hospitalist at UC San Diego Health and an assistant clinical professor at the University of California, San Diego.

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