The relationship between emergency department crowding and patient outcomes: a systematic review

J Nurs Scholarsh. 2014 Mar;46(2):106-15. doi: 10.1111/jnu.12055. Epub 2013 Dec 19.


Purpose: Emergency department (ED) crowding is a significant patient safety concern associated with poor quality of care. The purpose of this systematic review is to assess the relationship between ED crowding and patient outcomes.

Design: We searched the Medline search engine and relevant emergency medicine and nursing journals for studies published in the past decade that pertained to ED crowding and the following patient outcome measures: mortality, morbidity, patient satisfaction, and leaving the ED without being seen. All articles were appraised for study quality.

Findings: A total of 196 abstracts were screened and 11 articles met inclusion criteria. Three of the eleven studies reported a significant positive relationship between ED crowding and mortality either among patients admitted to the hospital or discharged home. Five studies reported that ED crowding is associated with higher rates of patients leaving the ED without being seen. Measures of ED crowding varied across studies.

Conclusions: ED crowding is a major patient safety concern associated with poor patient outcomes. Interventions and policies are needed to address this significant problem.

Clinical relevance: This review details the negative patient outcomes associated with ED crowding. Study results are relevant to medical professionals and those that seek care in the ED.

Keywords: Emergency department crowding; patient outcomes.

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Crowding*
  • Emergency Service, Hospital*
  • Humans
  • Patient Outcome Assessment*
  • Patient Safety
  • Quality of Health Care