Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Emergency department crowding negatively influences outcomes for children presenting with asthma: a population-based retrospective cohort study



Emergency department (ED) crowding may delay assessment and management and compromise outcomes. The association between the crowding metric time to physician initial assessment (PIA) and outcomes for children presenting for acute asthma is examined.


A population-based retrospective cohort of all presentations to 18 high-volume EDs during 2010–2014 in Alberta, Canada was created. Hourly, facility-specific median PIAs were calculated. Physician claims and hospitalizations data were linked for children (2–17 years) presenting for asthma.


Twenty-five thousand three hundred and eighty-three presentations (16,053 children) were made for asthma. Crowding was common in all hospitals and affected PIA more for lower acuity presentations. For every 1-h increase in median facility PIA, the individual-level PIA increased by 13 min (95% CI: 12, 14) for high, 43 min (95% CI: 42, 44) for moderate, and 60 min (95% CI: 58, 61) for the low acuity groups, when adjusted by predictors. Similarly, length of stay increased by 6, 36, and 45 min for the high, moderate, and low acuity groups, respectively. Increased PIA resulted in more departures prior to completion of care for the lower acuity groups.


Crowding adversely affects short-term outcomes of less ill children more than those who are more ill. When EDs experience increased crowding, care to patients with asthma is delayed; effective strategies to reduce crowding and delays to care are urgently needed.


  • For children presenting to EDs for asthma, increased time to physician initial assessment adversely affects short-term outcomes of patients with less severe presentations to a greater extent compared to those who are most severe.

  • Times to physician initial assessment are below recommended benchmarks; however, delays in care exist that impact LOS, odds of admission, and premature patient departures.

  • Pediatric patients with severe asthma are seen quickly and their outcomes are excellent.

  • Since crowding adversely affects short-term outcomes of pediatric patients with asthma, efforts to reduce ED crowding and assess patients with asthma in a more timely manner are needed.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Percent of children (aged 2–17) years presenting foor asthma and any condition by Canadian Triage and Acuity Scale (CTAS) groups.
Fig. 2: Coefficient estimates (with 95% confidence intervals) for ED crowding metric time to physician initial assessment (PIA) for each continuous outcome and each Canadian Triage and Acuity Scale (CTAS) group.


  1. 1.

    Affleck, A., Parks, P., Drummond, A., Rowe, B. & Ovens, H. Emergency department overcrowding and access block. Can. J. Emerg. Med. 15, 59–37 (2013).

    Article  Google Scholar 

  2. 2.

    Asplin, B. R. et al. A conceptual model of emergency department crowding. Ann. Emerg. Med. 42, 173–180 (2003).

    Article  Google Scholar 

  3. 3.

    Pines, J., Hollander, J., Localio, A. R. & Metlay, J. The association between Emergency Department crowding and hospital performance on antibiotic timing for pneumonia and percutaneous intervention for myocardial infarction. Acad. Emerg. Med. 13, 873–878 (2006).

    Article  Google Scholar 

  4. 4.

    Bekmezian, A., Fee, C., Bekmezian, S., Maselli, J. H. & Weber, E. Emergency department crowding and younger age are associated with delayed corticosteroid administration to children with acute asthma. Pediatr. Emerg. Care 29, 1075–1081 (2013).

  5. 5.

    Bernstein, S. L. et al. The effect of emergency department crowding on clinically oriented outcomes. Acad. Emerg. Med. 16, 1–10 (2009).

    Article  Google Scholar 

  6. 6.

    Carter, E. J., Pouch, S. M. & Larson, E. L. The relationship between emergency department crowding and patient outcomes: a systematic review. J. Nurs. Scholarsh. 46, 106–115 (2014).

    Article  Google Scholar 

  7. 7.

    World Health Organization. Asthma. (2018).

  8. 8.

    Public Health Agency of Canada. Report from the Canadian Chronic Disease Surveillance System: Asthma and Chronic Obstructive Pulmonary Disease (COPD) in Canada, 2018 (Public Health Agency of Canada, Ottawa, ON, 2018).

  9. 9.

    Moorman, J. E. et al. National surveillance of asthma: United States, 2001-2010. National Center for Health Statistics. Vital Health Stat. Ser. 3 3, 1–58 (2012).

    Google Scholar 

  10. 10.

    Camargo, C. A. Jr, Rachelefsky, G. & Schatz, M. Managing asthma exacerbations in the emergency department. Proc. Am. Thorac. Soc. 6, 357–366 (2009).

    Article  Google Scholar 

  11. 11.

    Sills, M. R., Fairclough, D., Ranade, D. & Kahn, M. G. Emergency department crowding is associated with decreased quality of care for children with acute asthma. Ann. Emerg. Med. 57, 191.e2007–200.e2007 (2011).

    Article  Google Scholar 

  12. 12.

    Canadian Institute of Health Information. The Canadian Enhancement of ICD-10 (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision) (Canadian Institute of Health Information, Ottawa, ON, 2001).

    Google Scholar 

  13. 13.

    Alberta Health and Wellness Data Disclosure Handbook (Alberta Health and Wellness, Edmonton, AB, 2003).

    Google Scholar 

  14. 14.

    Bullard, M. J., Unger, B., Spence, J., Grafstein, E. & CTAS National Working Group. Revisions to the Canadian Emergency Department Triage and Acuity Scale (CTAS) adult guidelines. Can. J. Emerg. Med. 10, 136–151 (2008).

    Article  Google Scholar 

  15. 15.

    Gravel, J., Manzano, S. & Arsenault, M. Validity of the Canadian Paediatric Triage and Acuity Scale in a tertiary care hospital. Can. J. Emerg. Med. 11, 23–28 (2009).

    Article  Google Scholar 

  16. 16.

    Wilkins, R, Peters, P. A. PCCF+ Version 5K* User’s Guide. Automated Geographic Coding Based on the Statistics Canada Postal Code Conversion Files, Including Postal Codes through May 2011. Catalogue 82F0086-XDB. Health Analysis Division, Statistics Canada, Ottawa, July 2012

  17. 17.

    Canadian Institute for Health Information. eNACRS Reports: Emergency Department Wait Time Indicators (Canadian Institute for Health Information, Ottawa, ON, 2020).

  18. 18.

    R Core Team. R: A Language and Environment for Statistical Computing (R Foundation for Statistical Computing, Vienna, 2018).

  19. 19.

    SAS Institute Inc. SAS 9.4 (SAS Institute Inc, Cary, NC, 2014).

    Google Scholar 

  20. 20.

    Institute of Medicine. Crossing the Quality Chasm: A New Health System for the 21st Century (The National Academies Press, Washington, DC, 2001).

  21. 21.

    Sills, M. R., Fairclough, D., Ranade, D. & Kahn, M. G. Emergency department crowding is associated with decreased quality of care for children. Pediatr. Emerg. Care 27, 837–845 (2011).

    Article  Google Scholar 

  22. 22.

    Morley, C., Unwin, M., Peterson, G. M., Stankovich, J. & Kinsman, L. Emergency department crowding: a systematic review of causes, consequences and solutions. PLoS ONE 13, e0203316 (2018).

    Article  Google Scholar 

  23. 23.

    Guttmann, A., Schull, M. J., Vermeulen, M. J. & Stukel, T. A. Association between waiting times and short term mortality and hospital admission after departure from emergency department: population based cohort study from Ontario, Canada. BMJ 342, d2983 (2011).

  24. 24.

    Kyriacou, D. N., Ricketts, V., Dyne, P. L., McCollough, M. D. & Talan, D. A. A 5-year time study analysis of emergency department patient care efficiency. Ann. Emerg. Med. 34, 326–335 (1999).

    CAS  Article  Google Scholar 

  25. 25.

    Preyde, M., Crawford, K. & Mullins, L. Patients’ satisfaction and wait times at Guelph General Hospital Emergency Department before and after implementation of a process improvement project. Can. J. Emerg. Med. 14, 157–168 (2012).

    Article  Google Scholar 

Download references


The authors thank Meng Lin of the Alberta SPOR data platform and AHS Research Data Services for providing health datasets. The authors also thank Jeffrey Bachman, MSc for accessing and preparing the Statistics Canada data and Larry Laliberte at the University of Alberta for providing the Statistics Canada data. This study was partially supported by summer student research awards to S.S. by Alberta Innovates-Health Solutions and the Women & Children’s Health Research Institute. This research has been funded by the generous support of the Stollery Children’s Hospital Foundation through the Women and Children’s Health Research Institute. This study was also supported by a grant from Alberta Health (AHW FP12-784). At the time of this project, B.H.R. was supported by Tier I Canada Research Chair in Evidence-based Emergency Medicine from the Canadian Institutes of Health Research (CIHR; Ottawa, Canada). The funding sources had no direct involvement in the study design, analysis, interpretation, or decision to submit this work.

Author information




S.S. obtained summer student funding, performed initial analyses, provided an initial draft of the manuscript, and critically reviewed the manuscript for important intellectual content. B.H.R. conceptualized and designed the study, obtained funding, interpreted results, and reviewed and revised the manuscript. M.B.O. contributed to study conceptualization, results interpretation, manuscript writing, and critically reviewed the manuscript for important intellectual content. R.J.R. conceptualized and designed the study, coordinated and supervised data extraction, obtained summer student funding, directed statistical analyses, performed modeling analyses, interpreted results, and reviewed and revised the manuscript. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.

Corresponding author

Correspondence to Rhonda J. Rosychuk.

Ethics declarations

Competing interests

B.H.R. received salary support from the Canadian Institutes of Health Research (CIHR; Ottawa, Canada). M.B.O., B.H.R., and R.J.R. are employees of the University of Alberta. The authors have no financial relationships with any organizations that might have an interest in the submitted work in the previous 3 years and no other relationship or activities that could appear to have influenced the submitted work. The authors have no financial relationships relevant to this article to disclose.


The Health Research Ethics Board of the University of Alberta (Pro00056282) approved this study and patient consent was not required.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Sagaidak, S., Rowe, B.H., Ospina, M.B. et al. Emergency department crowding negatively influences outcomes for children presenting with asthma: a population-based retrospective cohort study. Pediatr Res 89, 679–685 (2021).

Download citation


Quick links