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Association between emergency department length of stay and patient outcomes: a systematic review protocol

Burgess, Luke; Hines, Sonia; Kynoch, Kathryn

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JBI Database of Systematic Reviews and Implementation Reports: June 2018 - Volume 16 - Issue 6 - p 1361-1366
doi: 10.11124/JBISRIR-2017-003568
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Emergency departments (EDs) face constant pressures to provide urgent care services in a timely and easily accessible manner. The role of EDs is to provide initial diagnostic and therapeutic interventions, after which appropriate referral to specialist units or discharge from the ED takes place. Increasing demand for ED services can result in periods when demand exceeds supply, resulting in extended waits for treatment initiation, ED length of stay (LOS), and admission or discharge.1 In the event that someone is delayed in required admission to an inpatient unit, they are cared for in the ED. As the ED is not designed to function as an inpatient unit, the standard of care they receive can be sub-optimal in comparison to specialized inpatient care.2 Emergency department staff specialize in initiating emergency care and stabilizing acutely ill patients with undifferentiated illness; however, they often lack the skills and knowledge to care for the complex needs of patients with specific illness and injury.3,4 Extended ED occupation also prevents admission of newly arrived patients. Patient outcomes in ED are often time sensitive, where survival and/or recovery depend directly upon timely initiation of treatment and transfer to specialist services.5

The term “boarding” is used in the US to describe the situation in which an inpatient bed has been requested but is not yet available, and therefore the patient must stay in the ED until one becomes available. As new patients arrive, medical and nursing attention can be drawn away from those patients awaiting transfer to the inpatient bed, increasing the risk of preventable adverse events occurring. Several studies have suggested that increased LOS may lead to delayed or missed medications.6-8 Liu estimated that up to a quarter of patients experienced an undesirable event, such as missed medication, whilst boarding, and these were generally elderly patients with a higher number of co-morbidities.2 Emergency departments are considered a high risk environment for the occurrence of adverse events and the risk of an adverse event occurring in elderly people may increase as LOS does.2,6 Furthermore, an adverse event may lead to an increased inpatient LOS.9,10 Conversely, a retrospective cohort study of 1431 patients exploring the association between ED LOS and outcomes in patients with chest pain, pneumonia or cellulitis found that the boarding of patients was associated with missed medication administration, but found no association between extended ED LOS and adverse events for these groups.7

To confront challenges in accessing ED services, Australia introduced the National Emergency Access Target (NEAT) in 2011.1 The NEAT program was initiated to address public concerns regarding the standard of care in EDs related to issues such as access block, extended LOS, neglected or missed care, and adverse events for patients.1,9 The NEAT outlined that a specified percentage of patients in ED should be “admitted, referred for specialist assessment or discharged within four hours of presentation when it is clinically appropriate to do so”.1(p.16) The aims of the NEAT are to ensure that patients are not experiencing extended ED LOS and therefore not occupying ED beds for extended periods and consequently preventing new patients from accessing ED services. This initiative was based upon the “Four Hour Rule Program” in the UK. This rule mandated that a specified percentage of patients, initially 98%, should be seen, treated and discharged from the ED within four hours. The UK government, based on initial results, lauded the program as being “the envy of the world”.11(p.13) However, a 2010 systematic review that investigated the impact of four hour LOS targets on clinical outcomes concluded that, in the UK, the NEAT had not achieved a consistent improvement in the quality of care across EDs, with outcomes varying widely across hospitals. They concluded that other health systems should follow this program with caution and should more broadly consider the achievement of specified clinical outcomes rather than targets themselves.12 Baggoley concurs that time targets alone are not a perfect solution and argues that ED LOS is too simple to measure quality of care and other measures, e.g. standardized mortality ratios, should also be included.9

A retrospective chart review from 2015 found that interventions targeting only ED LOS did not result in improvements in quality of care measures and a broader approach is needed.13 Other studies have reported that ED LOS is important to understand as it may impact upon patient outcomes.14,15 A longitudinal study investigating the association of LOS on quality of care outcomes found that prolonged ED LOS was associated with decreased patient satisfaction and an increase in time to pain management for long bone fracture, as well as high leave without being seen rates.14 Further studies have reported similar findings of decreased patient satisfaction associated with prolonged ED LOS,15 or alternatively that ED LOS greater than eight hours was not associated with increased mortality, but with increased inpatient length of stay (IP LOS); this was more significant for patients over 75 years.16 Prolonged ED LOS may directly correlate with IP LOS as it has been reported that patients who stayed for eight to12 hours in an ED were 20% more likely to exceed the average IP LOS times for that state, and this rose to 50% more likely for ED stays greater than 12 hours.17

A systematic review of ED performance and quality of care measures found that LOS was the most common performance measure reported in the published literature, followed by patient and safety related outcomes.18 The impact ED LOS has upon quality of care and patient outcomes is unclear without a systematic review of the literature. A preliminary search has revealed that no systematic review has been conducted exploring the risks and outcomes associated with ED LOS. The only systematic review published in this area looked specifically at four-hour targets and their effect on clinical outcomes, and reported on the 98% target in the UK.12 This review will consider outcomes related to any period of LOS in the ED, and will not focus on any specific LOS targets, but may include studies that report on these. Given that current ED care models are based upon meeting LOS targets, a systematic review is required to provide a clear, in-depth understanding of the association between quality of care measures and patient outcomes.

Inclusion criteria


This review will consider studies that include individuals who spend time as a patient of an ED. This includes people who presented requesting treatment but left before medical treatment commenced. It will include both pediatric and adult populations.


Any period of time spent in an ED as a patient in minutes or hours. Emergency Departments may be interpreted as settings within hospitals designated, endorsed and equipped with the appropriate health professionals for the emergent care of acute health presentations.


Outcomes of interest to this review will include: mortality, omitted episodes of care (e.g. non-administration of prescribed medication), adverse events, time to treatment (e.g. time to analgesia or time to operating theater), inpatient LOS, leave without being seen rate and patient satisfaction.

Types of studies

This review will consider both experimental and quasi-experimental study designs including randomized controlled trials, non-randomized controlled trials, before and after studies and interrupted time-series studies. In addition, analytical observational studies including prospective and retrospective cohort studies and analytical cross-sectional studies will be considered for inclusion.


Search strategy

The search strategy will aim to find both published and unpublished studies. An initial limited search of PubMed and CINAHL has been undertaken followed by an analysis of the text words contained in the title and abstract, and of the index terms used to describe the article. This informed the development of a search strategy which will be tailored for each information source. A full search strategy for CINAHL is detailed in Appendix I. The reference lists of all studies selected for critical appraisal will be screened for additional studies.

Information sources

The databases to be searched include: PubMed, CINAHL, Embase, Web of Science.

The trial registers to be searched include: Cochrane Central Register of Controlled Trials, Australia and New Zealand Clinical Trials Registry and the ISRCTN Registry.

The search for unpublished studies will include: ProQuest Dissertations and Theses, and MedNar

Studies published in English will be included. Studies published since 2000 will be included as this was when ED LOS became an important focus of ED care models.12

Study selection

Following the search, all identified citations will be collated and uploaded into EndNote (Clarivate Analytics, PA, USA) and duplicates removed. Titles and abstracts will then be screened by two independent reviewers for assessment against the inclusion criteria of the review. Studies that meet the inclusion criteria will be retrieved in full and their details imported into the Joanna Briggs Institute System for the Unified Management, Assessment and Review of Information (JBI SUMARI).19 The full text of selected studies will be retrieved and assessed in detail against the inclusion criteria. Full text studies that do not meet the inclusion criteria will be excluded and reasons for exclusion will be provided in an appendix in the final systematic review report. Included studies will undergo a process of critical appraisal. The results of the search will be reported in full in the final report and presented in a PRISMA20 flow diagram. Any disagreements that arise between the reviewers will be resolved through discussion, or with a third reviewer.

Assessment of methodological quality

Selected studies will be critically appraised by two independent reviewers at the study level for methodological quality in the review using the standardized critical appraisal instruments from the Joanna Briggs Institute for the following study types: randomized control trials, quasi-experimental studies, case control studies, cohort studies, prevalence studies and analytical cross sectional studies.19 Any disagreements that arise will be resolved through discussion or with a third reviewer.

Following critical appraisal, studies that do not meet a certain quality threshold will be excluded. The decision to exclude will be guided by critical appraisal results as achieving high or moderate quality as follows. For randomized control trials, 10–13 “yes” responses out of the total 13 items on the instrument will be deemed as high quality, seven to nine as moderate quality, and less than seven as low quality. For cohort studies and quasi-experimental studies, achieving nine-11 “yes” responses out of the total 11 instrument items will be deemed as high quality, six to eight asmoderate quality, and less than six as low quality. For analytical cross-sectional studies, seven to eight will be considered high quality, five to six moderate quality, and less than five low quality. These outcomes as well as discussion amongst reviewers will be used to guide the decision.

Data extraction

Data will be extracted from papers included in the review using the standardized data extraction tools in JBI SUMARI by two independent reviewers. The data extracted will include specific details about the exposure of interest including different exposure categories if applicable, populations, study methods and outcomes or dependent variables of significance to the review question and specific objectives. Any disagreements that arise between the reviewers will be resolved through discussion or with a third reviewer. Authors of papers will be contacted to request missing or additional data where required.

Data synthesis

Papers will, where possible, be pooled in statistical meta-analysis using JBI SUMARI. Effect sizes will be expressed as either odds ratios (for dichotomous data and weighted (or standardized) mean differences (for continuous data) and their 95% confidence intervals will be calculated for analysis. Risk ratios, odds ratios, and/or hazard ratios will be pooled where appropriate. Random effects meta-analysis will be used, based on the guidance by Moola et al.21 Heterogeneity will be assessed by visual inspection of the forest plot in the first instance, then statistically using the standard chi-squared and I squared tests. If there is statistically significant heterogeneity, a narrative synthesis or graphical representation will be undertaken.

Subgroup analyses will be conducted where there is sufficient data to investigate the impact of high versus moderate quality studies, different populations, different health systems, different times of the year, and to assess whether there is a dose-response relationship between outcomes and LOS. Sensitivity analyses will be conducted to test the impact of specific studies. Where statistical pooling is not possible, the findings will be presented in narrative form including tables and figures to aid in data presentation where appropriate.

A funnel plot will be generated to assess publication bias if there are 10 or more studies included in a meta-analysis. Statistical tests for funnel plot asymmetry (Egger test, Begg test, Harbord test) will be performed where appropriate.

Assessing certainty in the findings

A Summary of Findings will be created using GRADEPro GDT software.23 The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach for grading the quality of evidence will be followed. The Summary of Findings will present the following information where appropriate: absolute risks for treatment and control, estimates of relative risk and a ranking of the quality of the evidence based on study limitations (risk of bias), indirectness, inconsistency, imprecision and publication bias.22

The following outcomes will be included in the Summary of Findings: mortality, adverse events, omitted care, time to treatment, IP LOS, leave without being seen rate and patient satisfaction.

Appendix I: Search strategy for CINAHL

  • 1. “length of stay” OR (MH “Length of Stay”)
  • 2. boarding
  • 3. 1 OR 2
  • 4. Outcome OR quality OR “quality of care” OR risk
  • 5. satisfaction OR (MH “Patient Satisfaction”)
  • 6. “time to treatment”
  • 7. mortality OR “adverse event
  • 8. 4 OR 5 OR 6 OR 7
  • 9. emergency OR “emergency department” Or “accident and emergency” OR “emergency room” OR “casualty department” OR (MH “Emergency Service+”)
  • 10. 3 AND 8 AND 9
  • 11. Limiters Applied: Published Date: 2000-; English Language.


1. Sullivan C, Staib A, Khanna S, Good NM, Boyle J, Cattell R, et al. The National Emergency Access Target (NEAT) and the 4-hour rule: time to review the target. Med J Aust 2016; 204 9:354.
2. Liu SW, Thomas SH, Gordon JA, Hamedani AG, Weissman JS. A pilot study examining undesirable events among emergency department–boarded patients awaiting inpatient beds. Ann Emerg Med 2009; 54 3:381–385.
3. Chalfin DB, Trzeciak S, Likourezos A, Baumann BM, Dellinger RP. DELAY-ED study group. Impact of delayed transfer of critically ill patients from the emergency department to the intensive care unit. Crit Care Med 2007; 35 6:1477–1483.
4. Liu SW, Chang Y, Camargo CA Jr, Weissman JS, Walsh K, Schuur JD, et al. A mixed-methods study of the quality of care provided to patients boarding in the emergency department: comparing emergency department and inpatient responsibility models. Medical Care Research and Review 2012; 69 6:679–698.
5. Puskarich MA, Trzeciak S, Shapiro NI, Heffner AC, Kline JA, Jones AE, et al. Outcomes of patients undergoing early sepsis resuscitation for cryptic shock compared with overt shock. Resuscitation 2011; 82 10:1289–1293.
6. Singer AJ, Thode HC Jr, Viccellio P, Pines JM. The association between length of emergency department boarding and mortality. Acad Emerg Med 2011; 18 12:1324–1329.
7. Liu SW, Chang Y, Weissman JS, Griffey RT, Thomas J, Nergui S, et al. An empirical assessment of boarding and quality of care: delays in care among chest pain, pneumonia, and cellulitis patients. Acad Emerg Med 2011; 18 12:1339–1348.
8. Sri-On J, Chang Y, Curley DP, Camargo CA, Weissman JS, Singer SJ, et al. Boarding is associated with higher rates of medication delays and adverse events but fewer laboratory-related delays. Am J Emerg Med 2014; 32 9:1033–1036.
9. Baggoley C, Owler B, Grigg M, Wellington H, Monaghan M, Hartley-Jones J. Expert panel review of elective surgery and emergency access targets under the national partnership agreement on improving public hospital services. Report to the Council of Australian Governments. June 2011.
10. Ackroyd-Stolarz S, Guernsey JR, Mackinnon N, Kovacs G. The association between a prolonged stay in the emergency department and adverse events in older patients admitted to hospital: a retrospective cohort study. BMJ Qual Saf 2011; 20 7:564–569.
11. Alberti G. Transforming emergency care in England: a report by Professor Sir George Alberti. London: Department of Health (UK); 2004.
12. Jones P, Schimanski K. The four hour target to reduce emergency department “waiting time”: a systematic review of clinical outcomes. Emerg Med Australas 2010; 22 5:391–398.
13. Vermeulen MJ, Guttmann A, Stukel TA, Kachra A, Sivilotti ML, Rowe BH, et al. Are reductions in emergency department length of stay associated with improvements in quality of care? A difference-in-differences analysis. BMJ Qual Saf 2016; 25:489–498.
14. Chang AM, Lin A, Fu R, McConnell KJ, Sun B. Associations of Emergency Department Length of Stay With Publicly Reported Quality-of-care Measures. Acad Emerg Med 2017; 24 2:246–250.
15. Pines JM, Iyer S, Disbot M, Hollander JE, Shofer FS, Datner EM. The effect of emergency department crowding on patient satisfaction for admitted patients. Acad Emerg Med 2008; 15 9:825–831.
16. Chong CP, Haywood C, Barker A, Lim WK. Is Emergency Department length of stay associated with inpatient mortality? Australas J Ageing 2013; 32 2:122–124.
17. Liew D, Liew D, Kennedy MP. Emergency department length of stay independently predicts excess inpatient length of stay. Med J Aust 2003; 179 10:524–527.
18. Sørup CM, Jacobsen P, Forberg JL. Evaluation of emergency department performance–a systematic review on recommended performance and quality-in-care measures. Scand J Trauma Resusc Emerg Med 2013; 21 1:62.
19. The Joanna Briggs Institute. Joanna Briggs Institute Reviewers’ Manual: 2014 edition. Australia: The Joanna Briggs Institute; 2014.
20. Moher D, Liberati A, Tetzlaff J, Altman DG, Group P. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS medicine 2009; 6 7:e1000097.
21. Moola S, Munn Z, Sears K, Sfetcu R, Currie M, Lisy K, et al. Conducting systematic reviews of association (etiology): The Joanna Briggs Institute's approach. Int J Evid Based Healthc 2015; 13 3:163–169.
22. The Joanna Briggs Institute Levels of Evidence, Grades of Recommendation Working Party. Summary of Findings Tables for Joanna Briggs Institute Systematic Reviews. Australia: The Joanna Briggs Institute; 2016.
23. GRADEpro GDT: GRADEpro Guideline Development Tool [Software]. McMaster University, 2015 (developed by Evidence Prime, Inc.). Available from

Boarding; emergency department; length of stay; patient outcomes; quality of care