Downloaded from http://emj.bmj.com/ on November 13, 2015 - Published by group.bmj.com
Original article
Age and sex-dependent trends in pulmonary embolism testing and derivation of a clinical decision rule for young patients John Mongan,1 Jeffrey Kline,2 Rebecca Smith-Bindman1,3,4 ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ emermed-2014-204531). 1
Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA 2 Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA 3 Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA 4 Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, California, USA Correspondence to Dr John Mongan, Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue Box 0628, Rm. M372, San Francisco, CA 94143, USA; [email protected] Received 20 November 2014 Revised 17 February 2015 Accepted 20 February 2015 Published Online First 9 March 2015
ABSTRACT Importance Despite low prevalence of pulmonary embolism (PE) in young adults, they are frequently imaged for PE, which involves radiation exposure and substantial financial cost. Objective Determine the use and positive proportions for PE imaging by age, differences in clinical presentation of PE by age and the projected impact of an age-targeted decision rule. Design Analysis of two national population-based datasets: the 2009 Nationwide Emergency Department Sample, a 20% sample of US emergency departments (EDs) and the 2003–2006 Pulmonary Embolism Rule-out Criteria (PERC) dataset, a multisite cohort of ED patients with suspected PE from 12 US EDs. Results Prevalence of PE was 10 times lower in young patients (18–35 years) than in older patients (>65 years) (0.06% vs 0.60%, p65 All ages
Patients suspected of PE
Patients with PE imaging
PE diagnoses
Proportion of imaging positive for PE (%)
1895 2527 2003 1463 7888
974 (51.4%) 1378 (54.5%) 1323 (66.0%) 1194 (81.6%) 4869 (61.7%)
72 (3.8%) 119 (4.7%) 137 (6.8%) 149 (10.2%) 477 (6.0%)
7.4 8.6 10.4 12.5 9.8
490 811 709 586 2596
215 (43.9%) 433 (53.4%) 460 (64.9%) 482 (82.3%) 1590 (61.2%)
23 (4.7%) 60 (7.4%) 59 (8.3%) 68 (11.6%) 210 (8.1%)
10.7 13.9 12.8 14.1 13.2
1405 1716 1294 877 5292
759 (54.0%) 945 (55.1%) 863 (66.7%) 712 (81.2%) 3279 (62.0%)
49 (3.5%) 59 (3.4%) 78 (6.0%) 81 (9.2%) 267 (5.0%)
6.5 6.2 9.0 11.4 8.1
Mongan J, et al. Emerg Med J 2015;32:840–845. doi:10.1136/emermed-2014-204531
Downloaded from http://emj.bmj.com/ on November 13, 2015 - Published by group.bmj.com
Original article but there are fewer missed PEs. For PERC-35, 51% of patients would avoid testing with a 0.6% missed PE rate in those excluded from testing. We estimate that if PERC-35 had been applied to the entire population of 18–35 year olds imaged in US EDs for low clinical suspicion PE in 2009, approximately 367 000 CTAs and 53 000 V/Q scans would have been avoided, and 2200 diagnoses of PE would be missed due to exclusion from testing.
Clinical predictors of PE Clinical predictors of PE varied by age (table 4). Tachycardia, cancer and chest pain were significant predictors of PE only among patients older than 35 years of age and fever was a significant predictor only in the younger age group. There were few differences between sexes in significant predictors of PE other than exogenous oestrogen and pregnancy.
Clinical decision rules and patient impact Age-dependent differences in clinical predictors of PE led us to modify the PERC decision rule to improve performance in young patients. The PERC rule excludes patients from PE testing if they do not have any of the following indicators: age >49 years, tachycardia ( pulse >99), hypoxia ( pulse oximetry
Original article
Age and sex-dependent trends in pulmonary embolism testing and derivation of a clinical decision rule for young patients John Mongan,1 Jeffrey Kline,2 Rebecca Smith-Bindman1,3,4 ▸ Additional material is published online only. To view please visit the journal online (http://dx.doi.org/10.1136/ emermed-2014-204531). 1
Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA 2 Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA 3 Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA 4 Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, California, USA Correspondence to Dr John Mongan, Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue Box 0628, Rm. M372, San Francisco, CA 94143, USA; [email protected] Received 20 November 2014 Revised 17 February 2015 Accepted 20 February 2015 Published Online First 9 March 2015
ABSTRACT Importance Despite low prevalence of pulmonary embolism (PE) in young adults, they are frequently imaged for PE, which involves radiation exposure and substantial financial cost. Objective Determine the use and positive proportions for PE imaging by age, differences in clinical presentation of PE by age and the projected impact of an age-targeted decision rule. Design Analysis of two national population-based datasets: the 2009 Nationwide Emergency Department Sample, a 20% sample of US emergency departments (EDs) and the 2003–2006 Pulmonary Embolism Rule-out Criteria (PERC) dataset, a multisite cohort of ED patients with suspected PE from 12 US EDs. Results Prevalence of PE was 10 times lower in young patients (18–35 years) than in older patients (>65 years) (0.06% vs 0.60%, p65 All ages
Patients suspected of PE
Patients with PE imaging
PE diagnoses
Proportion of imaging positive for PE (%)
1895 2527 2003 1463 7888
974 (51.4%) 1378 (54.5%) 1323 (66.0%) 1194 (81.6%) 4869 (61.7%)
72 (3.8%) 119 (4.7%) 137 (6.8%) 149 (10.2%) 477 (6.0%)
7.4 8.6 10.4 12.5 9.8
490 811 709 586 2596
215 (43.9%) 433 (53.4%) 460 (64.9%) 482 (82.3%) 1590 (61.2%)
23 (4.7%) 60 (7.4%) 59 (8.3%) 68 (11.6%) 210 (8.1%)
10.7 13.9 12.8 14.1 13.2
1405 1716 1294 877 5292
759 (54.0%) 945 (55.1%) 863 (66.7%) 712 (81.2%) 3279 (62.0%)
49 (3.5%) 59 (3.4%) 78 (6.0%) 81 (9.2%) 267 (5.0%)
6.5 6.2 9.0 11.4 8.1
Mongan J, et al. Emerg Med J 2015;32:840–845. doi:10.1136/emermed-2014-204531
Downloaded from http://emj.bmj.com/ on November 13, 2015 - Published by group.bmj.com
Original article but there are fewer missed PEs. For PERC-35, 51% of patients would avoid testing with a 0.6% missed PE rate in those excluded from testing. We estimate that if PERC-35 had been applied to the entire population of 18–35 year olds imaged in US EDs for low clinical suspicion PE in 2009, approximately 367 000 CTAs and 53 000 V/Q scans would have been avoided, and 2200 diagnoses of PE would be missed due to exclusion from testing.
Clinical predictors of PE Clinical predictors of PE varied by age (table 4). Tachycardia, cancer and chest pain were significant predictors of PE only among patients older than 35 years of age and fever was a significant predictor only in the younger age group. There were few differences between sexes in significant predictors of PE other than exogenous oestrogen and pregnancy.
Clinical decision rules and patient impact Age-dependent differences in clinical predictors of PE led us to modify the PERC decision rule to improve performance in young patients. The PERC rule excludes patients from PE testing if they do not have any of the following indicators: age >49 years, tachycardia ( pulse >99), hypoxia ( pulse oximetry
