top of page
screen background 2.png

How Does Emergency Department Crowding Impact Care? (Part 2 Of 3)

May 26th, 2021
humanising healthcare

This article is the second in a three-part series which seeks to dissect the challenge of emergency department (ED) crowding; why it occurs, why it’s a problem and what we need to do to overcome it. The creation of this series is driven by the ever-pressing need to secure the sustainability of our EDs, which move closer and closer to breaking point with each day. This series has been curated with the support of senior Emergency Medicine Consultants from NHS England.

In this article, we will break down the impact of ED crowding on patient care to explain why this problem urgently requires our attention.


At a high-level, ED crowding matters because of its association with avoidable and preventable morbidity and mortality [1]. A consistent correlation between patients arriving into crowded emergency departments and excess mortality and length of stay (LOS) has been found internationally [2,3]. Even more concerning is the fact that it’s often found to be the critically ill, the mentally ill, the elderly, and the vulnerable who are most affected [4]. With ED crowding also being the most common cause of delayed emergency care, it’s no wonder that is thought to be ‘one of the greatest threats to patient safety in the provision of emergency care around the world’ [5].


Diving deeper, ED crowding has direct effects on patient outcomes and the quality of care delivery. We list exactly how below.

Patient Outcomes

In terms of its impact on patient outcomes, ED crowding has been associated with:


  • High patient readmission rates, with a study showing ED crowding is associated with readmission rates for conditions such as pneumonia or acute myocardial infarction [6].

  • Increased walkouts due to perceived ED LOS, with a study stating that long waiting times was cited as the main reason (61%) for leaving the ED without treatment [7].

  • Morbidity, with studies even showing an association between ED crowding and higher incidence of hospital-acquired pneumonia [8].

  • Prolonged hospitalisation, with one study of 770 patients finding ED crowding decreased the likelihood of timely implementation of the resuscitation bundle [8-10].

  • Medication errors and adverse effects, with a study showing that the presence of preventable medical errors (PMEs) was twofold higher in crowded EDs than those at optimum capacity [11-14].

  • Mortality, with studies finding increased inpatient mortality amongst the critically ill [6, 8-10, 15-21].

Quality Of Care Delivery

ED crowding also reduces the capacity for healthcare professionals to deliver high quality care. Associations include:

  • Delayed assessment or treatment, with a study showing that implementation rates for protocolised sepsis care in crowded EDs decreased from 71.3% to 50.5% [22-28].

  • High cost of treatment, with ED crowding causing 300 inpatient deaths, 6,200 hospital days and $17 million in costs in one study [4].

  • Low satisfaction, with a study of 1,469 patients finding that ED crowding was predictive of lower ED satisfaction and lower satisfaction with the entire hospitalisation [6,24,29,30].

  • High workload, with a pneumonia study showing that only 61% of patients received antibiotics within 4 hours, despite having a state-mandated ratio of doctors and nurses [31].

  • Discharging patients with high-risk clinical features, with studies showing that crowding may affect clinical decision-making in conditions such as TIAs or minor strokes [32].

  • High patient readmission rates to general wards and ICU, with studies of pneumonia patients finding that antibiotic administration times can be delayed due to ED crowding [31].

  • Longer time to investigate patients’ medical conditions, with wait times in crowded EDs being shown in studies to be at least 10 minutes longer than in mean capacity EDs [31].

  • Poor infection prevention and control measures, with hand hygiene compliance shown to be at only 29% in one study of a crowded ED [33].

  • Low compliance with standards of care, with a study of 770 sepsis patients showing that high crowding groups had a significant associate with lower compliance [9].


It quickly becomes clear that this is a near universal problem, rather than just failings at an individual case level. ED departments are extremely heterogeneous; their unique pinch points and the impacts of crowding on their patients and staff will change daily, from minute to minute, hour to hour. Emergency care leaders can act on experience and gut feeling to try and combat crowding and its effects, but there is only so much they can do without a reliable measure to predict upcoming problems and judge what the impact of their proposed solutions or interventions will be.


The final article in this series will explore and evaluate various solutions to ED crowding currently in place before outlining our proposed new approach to tackling this pressing problem.

Contact Us

electronRx partner with healthcare providers, payers and pharmaceutical companies across the globe, harnessing the power of digital biomarkers to manage chronic conditions effectively.


Want to learn more or request a demo with our clinical team?

Thanks! We'll be in touch soon.


  1. Wyatt et al, 2017 - Wyatt S, Child K, Hood A, Cooke M, Mohammed MA. Changes in admission thresholds in English emergency departments. Emerg Med J. 2017 Dec;34(12):773–779.

  2. Moskop JC, Sklar DP, Geiderman JM, Schears RM, Bookman KJ. Emergency department crowding, part 1--concept, causes, and moral consequences. Ann Emerg Med. 2009 May;53(5):605–611.

  3. Sprivulis et al, 2006 - Sprivulis PC, Da Silva J-A, Jacobs IG, Frazer ARL, Jelinek GA. The association between hospital overcrowding and mortality among patients admitted via Western Australian emergency departments. Med J Aust. 2006 Mar 6;184(5):208–212.

  4. Sun et al, 2013 - Sun BC, Hsia RY, Weiss RE et al. Effect of emergency department crowding on outcomes of admitted patients. Ann Emerg Med. 2013 Jun;61(6):605–611.e6.

  5. Fatovich D. Access block causes emergency department overcrowding and ambulance diversion in Perth, Western Australia. Emerg Med J. 2005;22(5):351-354.

  6. Mullins PM, Pines JM. National ED crowding and hospital quality: results from the 2013 Hospital Compare data. The American journal of emergency medicine. 2014;32(6):634–9.

  7. van der Linden MC, Lindeboom R, van der Linden N, van den Brand CL, Lam RC, Lucas C, et al. Walkouts from the emergency department: characteristics, reasons and medical care needs. European Journal of Emergency Medicine. 2014;21(5):354–9. doi: 10.1097/MEJ.0000000000000086.

  8. Verelst S, Wouters P, Gillet J-B, Van den Berghe G. Emergency department crowding in relation to in-hospital adverse medical events: a large prospective observational cohort study. The Journal of emergency medicine. 2015;49(6):949–61.

  9. Shin TG, Jo IJ, Choi DJ, Kang MJ, Jeon K, Suh GY, et al. The adverse effect of emergency department crowding on compliance with the resuscitation bundle in the management of severe sepsis and septic shock. Critical Care. 2013;17(5):R224. doi: 10.1186/cc13047.

  10. Cha WC, Do Shin S, Cho JS, Song KJ, Singer AJ, Kwak YH. The association between crowding and mortality in admitted pediatric patients from mixed adult-pediatric emergency departments in Korea. Pediatric emergency care. 2011;27(12):1136–41. doi: 10.1097/PEC.0b013e31823ab90b.

  11. Dubin J, Blumenthal J, Milzman D. 127 Emergency Department Crowding and Physician Inexperience are Synergistically Associated With Increased Physician Errors. Annals of Emergency Medicine. 2013;62:4.

  12. Epstein SK, Huckins DS, Liu SW, Pallin DJ, Sullivan AF, Lipton RI, et al. Emergency department crowding and risk of preventable medical errors. Internal and emergency medicine. 2012;7(2):173–80. doi: 10.1007/s11739-011-0702-8.

  13. Kulstad EB, Sikka R, Sweis RT, Kelley KM, Rzechula KH. ED overcrowding is associated with an increased frequency of medication errors. The American journal of emergency medicine. 2010;28(3):304–9.

  14. Pines JM, Pollack Jr CV, Diercks DB, Chang AM, Shofer FS, Hollander JE. The association between emergency department crowding and adverse cardiovascular outcomes in patients with chest pain. Academic Emergency Medicine. 2009;16(7):617–25.

  15. Derose SF, Gabayan GZ, Chiu VY, Yiu SC, Sun BC. Emergency department crowding predicts admission length-of-stay but not mortality in a large health system. Medical care. 2014;52(7):602. doi: 10.1097/MLR.0000000000000141.

  16. Hong KJ, Do Shin S, Song KJ, Cha WC, Cho JS. Association between ED crowding and delay in resuscitation effort. The American journal of emergency medicine. 2013;31(3):509–15.

  17. Jo S, Jin YH, Lee JB, Jeong T, Yoon J, Park B. Emergency department occupancy ratio is associated with increased early mortality. The Journal of emergency medicine. 2014;46(2):241–9.

  18. Jo S, Jeong T, Jin YH, Lee JB, Yoon J, Park B. ED crowding is associated with inpatient mortality among critically ill patients admitted via the ED: post hoc analysis from a retrospective study. The American journal of emergency medicine. 2015;33(12):1725–31.

  19. McCusker J, Vadeboncoeur A, Lévesque JF, Ciampi A, Belzile E. Increases in emergency department occupancy are associated with adverse 30‐day outcomes. Academic Emergency Medicine. 2014;21(10):1092–100.

  20. Van Der Linden N, Van Der Linden MC, Richards JR, Derlet RW, Grootendorst DC, Van Den Brand CL. Effects of emergency department crowding on the delivery of timely care in an inner-city hospital in the Netherlands. European Journal of Emergency Medicine. 2016;23(5):337–43. doi: 10.1097/MEJ.0000000000000268.

  21. Wu D, Zhou X, Ye L, Gan J, Zhang M. Emergency department crowding and the performance of damage control resuscitation in major trauma patients with hemorrhagic shock. Academic Emergency Medicine. 2015;22(8):915–21.

  22. Depinet HE, Iyer SB, Hornung R, Timm NL, Byczkowski TL. The effect of emergency department crowding on reassessment of children with critically abnormal vital signs. Academic Emergency Medicine. 2014;21(10):1116–20.

  23. Gaieski DF, Agarwal AK, Mikkelsen ME, Drumheller B, Sante SC, Shofer FS, et al. The impact of ED crowding on early interventions and mortality in patients with severe sepsis. The American journal of emergency medicine. 2017;35(7):953–60. doiI: 10.1016/j.ajem.2017.01.061.

  24. Wang H, Robinson RD, Cowden CD, Gorman VA, Cook CD, Gicheru EK, et al. Use of the SONET score to evaluate Urgent Care Center overcrowding: a prospective pilot study. BMJ open. 2015;5(4):e006860. doi: 10.1136/bmjopen-2014-006860.

  25. Wiler JL, Bolandifar E, Griffey RT, Poirier RF, Olsen T. An emergency department patient flow model based on queueing theory principles. Academic Emergency Medicine. 2013;20(9):939–46.

  26. Pines JM, Hollander JE. Emergency department crowding is associated with poor care for patients with severe pain. Annals of emergency medicine. 2008;51(1):1–5.

  27. Fee C, Weber EJ, Maak CA, Bacchetti P. Effect of emergency department crowding on time to antibiotics in patients admitted with community-acquired pneumonia. Annals of emergency medicine. 2007;50(5):501–9.

  28. Reznek MA, Murray E, Youngren MN, Durham NT, Michael SS. Door-to-imaging time for acute stroke patients is adversely affected by emergency department crowding. Stroke. 2017;48(1):49–54.

  29. Pines JM, Iyer S, Disbot M, Hollander JE, Shofer FS, Datner EM. The effect of emergency department crowding on patient satisfaction for admitted patients. Academic Emergency Medicine. 2008;15(9):825–31.

  30. Tekwani KL, Kerem Y, Mistry CD, Sayger BM, Kulstad EB. Emergency department crowding is associated with reduced satisfaction scores in patients discharged from the emergency department. Western Journal of Emergency Medicine. 2013;14(1).

  31. Fee C, Weber EJ, Bacchetti P, Maak CA. Effect of emergency department crowding on pneumonia admission care components. The American journal of managed care. 2011;17(4):269–78. PMID: 21615197.

  32. Ben‐Yakov M, Kapral MK, Fang J, Li S, Vermeulen MJ, Schull MJ. The association between emergency department crowding and the disposition of patients with transient ischemic attack or minor stroke. Acad Emerg Med. 2015;22(10):1145–54. PMID: 26398233.

  33. Muller MP, Carter E, Siddiqui N, Larson E. Hand hygiene compliance in an emergency department: the effect of crowding. Academic Emergency Medicine. 2015;22(10):1218–21. doi: 10.1111/acem.12754.

bottom of page