[Skip to Content]
Access to paid content on this site is currently suspended due to excessive activity being detected from your IP address 34.204.191.31. Please contact the publisher to request reinstatement.
[Skip to Content Landing]
Table.  
Positive CTPA Examinations for All Physiciansa
Positive CTPA Examinations for All Physiciansa
1.
Chen  YA, Gray  BG, Bandiera  G, MacKinnon  D, Deva  DP.  Variation in the utilization and positivity rates of CT pulmonary angiography among emergency physicians at a tertiary academic emergency department.  Emerg Radiol. 2015;22(3):221-229.PubMedGoogle ScholarCrossref
2.
Worrall  JC, Jama  S, Stiell  IG.  Radiation doses to emergency department patients undergoing computed tomography.  CJEM. 2014;16(6):477-484.PubMedGoogle ScholarCrossref
3.
Stokes  ME, Davis  CS, Koch  GG.  Categorical Data Analysis Using the SAS System, 3e. Cary, NC: SAS Institute; 2012.
4.
Mountain  D, Keijzers  G, Chu  K,  et al.  RESPECT-ED: Rates of pulmonary emboli (PE) and sub-segmental PE with modern computed tomographic pulmonary angiograms in emergency departments: a multi-center observational study finds significant yield variation, uncorrelated with use or small PE rates.  PLoS One. 2016;11(12):e0166483.PubMedGoogle ScholarCrossref
5.
Kindermann  DR, McCarthy  ML, Ding  R,  et al.  Emergency department variation in utilization and diagnostic yield of advanced radiography in diagnosis of pulmonary embolus.  J Emerg Med. 2014;46(6):791-799.PubMedGoogle ScholarCrossref
6.
Perelas  A, Dimou  A, Saenz  A,  et al.  CT pulmonary angiography utilization in the emergency department: diagnostic yield and adherence to current guidelines.  Am J Med Qual. 2015;30(6):571-577.PubMedGoogle ScholarCrossref
Research Letter
Less Is More
March 2018

Association of Lower Diagnostic Yield With High Users of CT Pulmonary Angiogram

Author Affiliations
  • 1Department of Radiology, McGill University Health Centre, Montréal, Québec, Canada
  • 2Clinical Practice Assessment Unit, Department of Medicine, McGill University Health Centre, Montréal, Québec, Canada
  • 3Department of Emergency Medicine, McGill University Health Centre, Montréal, Québec, Canada
JAMA Intern Med. 2018;178(3):412-413. doi:10.1001/jamainternmed.2017.7552

Pulmonary embolism (PE) can be life-threatening and, when suspected, is usually investigated by computed tomographic pulmonary angiogram (CTPA). Concerns related to overutilization and harmful ionizing radiation have identified CTPA as an area in need of resource stewardship.1,2 The purpose of this study was to explore interphysician variability in CTPA diagnostic yield and to identify any associated physician characteristics that could inform an intervention to reduce overuse in our institution.

Methods

We retrospectively reviewed all CTPAs at an academic teaching hospital in Montreal, Quebec, Canada, from September 2014 to January 2016. Studies were classified as positive or negative; indeterminate examinations, and those performed for chronic pulmonary emboli were excluded. A total of 1394 examinations ordered by 182 physicians were included, of which 199 (14.3%) were positive and 1195 (85.7%) were negative. A multivariable logistic regression analysis was performed to explore whether physician specialty, years in practice, physician sex, or total numbers of studies ordered per physician were associated with CTPA diagnostic yield. We used a generalized estimating equations (GEE) approach to account for patients who underwent repeated examinations over the study period.3 Statistical tests of hypothesis were 2-sided with a significance of P ≤ .05. All analyses were performed using SAS statistical software (version 9.4, SAS Institute Inc). The McGill University Health Centre research ethics board approved this study.

Results

According to our analysis using GEE logistic regression, the odds of a positive CTPA decreased as the total number of scans ordered per physician increased (Table). For each additional 10 studies ordered, the odds of a positive result decreased (odds ratio [OR], 0.76; 95% CI, 0.73-0.79). Increasing patient age was associated with a higher diagnostic yield (OR, 1.02 per year; 95% CI, 1.01-1.03). Physician years of experience (OR, 1.01; 95% CI, 0.99-1.02; P = .39), physician sex (OR, 1.14; 95% CI, 0.79-1.63; P = .49), and studies originating from the emergency department (ER) (OR, 1.11; 95% CI, 0.75-1.65; P = .60) did not show a statistically significant association. When restricting the analysis to those studies performed by ER physicians, 123 of 974 (12.6%) were positive, and the OR for positivity for each additional 10 scans ordered decreased in a similar manner (OR, 0.74; 95% CI, 0.71-0.78).

Discussion

Our institutional yield of positive CTPA was 14.3%, which is similar to prior reported studies.4-6 However, closer inspection demonstrated that there was substantial interphysician variability, with individual positivity rates ranging between 0% to 33.3%. Our study suggests that individual demographic features, such as specialty and professional experience are not significantly associated with diagnostic yield; however, physicians who ordered a greater volume of scans compared with their peers had a markedly reduced diagnostic yield.

Limitations

Limitations of our study included its retrospective design and the inadequate charting of parameters, which precluded the derivation of a preexamination clinical probability score. In addition, owing to limitations in data collection, we were unable to determine the denominator of patients presenting with PE-related symptoms examined by each physician. Notably, in the cohort of ER physicians shift allotment was generally randomized and we did not observe any systematic biases.

Conclusions

Among physicians who ordered a greater number of CTPA scans, we observed a statistically significant decrease in the proportion of positive results. This association may reflect a fundamental relationship between individual physician overutilization and decreasing diagnostic yield, and is deserving of greater attention. Peer-relative rates of utilization are easily quantified from electronic databases, and can identify physicians most likely to benefit from individual performance feedback and decision support tools. Based on these findings, our group has designed automated yield monitoring and feedback, with the aim of closing the gap between individual physician performance in our institution. We hope this will translate to a substantial reduction in unnecessary CTPA scans along with the associated complications that may occur owing to unnecessary radiation, overdiagnosis, and overtreatment.

Back to top
Article Information

Corresponding Author: Emily G. McDonald, MD, Clinical Practice Assessment Unit, Department of Medicine, McGill University Health Centre, 1001 Blvd Décarie, Montréal, QC, H4A 3J1, Canada (emily.mcdonald@mcgill.ca).

Accepted for Publication: October 30, 2017.

Published Online: January 8, 2018. doi:10.1001/jamainternmed.2017.7552

Author Contributions: Drs Chong and McDonald had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Drs McDonald and Gallix contributed equally to the work.

Study concept and design: Chong, Lee, Attarian, McDonald, Gallix.

Acquisition, analysis, or interpretation of data: Chong, Lee, Attarian, Sivakumaran, Troquet, Gallix.

Drafting of the manuscript: Chong, Attarian.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Chong, Attarian.

Obtained funding: Gallix.

Administrative, technical, or material support: Chong, Lee, Attarian, McDonald, Gallix.

Study supervision: Chong, Troquet, McDonald, Gallix.

Conflict of Interest Disclosures: None reported.

References
1.
Chen  YA, Gray  BG, Bandiera  G, MacKinnon  D, Deva  DP.  Variation in the utilization and positivity rates of CT pulmonary angiography among emergency physicians at a tertiary academic emergency department.  Emerg Radiol. 2015;22(3):221-229.PubMedGoogle ScholarCrossref
2.
Worrall  JC, Jama  S, Stiell  IG.  Radiation doses to emergency department patients undergoing computed tomography.  CJEM. 2014;16(6):477-484.PubMedGoogle ScholarCrossref
3.
Stokes  ME, Davis  CS, Koch  GG.  Categorical Data Analysis Using the SAS System, 3e. Cary, NC: SAS Institute; 2012.
4.
Mountain  D, Keijzers  G, Chu  K,  et al.  RESPECT-ED: Rates of pulmonary emboli (PE) and sub-segmental PE with modern computed tomographic pulmonary angiograms in emergency departments: a multi-center observational study finds significant yield variation, uncorrelated with use or small PE rates.  PLoS One. 2016;11(12):e0166483.PubMedGoogle ScholarCrossref
5.
Kindermann  DR, McCarthy  ML, Ding  R,  et al.  Emergency department variation in utilization and diagnostic yield of advanced radiography in diagnosis of pulmonary embolus.  J Emerg Med. 2014;46(6):791-799.PubMedGoogle ScholarCrossref
6.
Perelas  A, Dimou  A, Saenz  A,  et al.  CT pulmonary angiography utilization in the emergency department: diagnostic yield and adherence to current guidelines.  Am J Med Qual. 2015;30(6):571-577.PubMedGoogle ScholarCrossref
×