Abstract
Background
Overcrowding in emergency departments (EDs) is a major problem worldwide, poses a significant and ongoing threat to the quality of healthcare services, as it affects the efficiency of hospital operations on multiple levels. It has been consistently linked with prolong length of stay, increase waiting time and treatment delays, higher patient mortality, and increased burnout among healthcare workers. Although widely recognized, the causes, consequences, and effectiveness of interventions to address ED overcrowding remain variably reported across different healthcare settings, particularly between high-income countries and low- and middle-income countries (LMICs).
Objective
The objective of this study was to critically analyze and synthesize global evidence on the causes, consequences, and effective interventions, related to overcrowding in the emergency department.
Methods
This systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A thorough search was performed across PubMed/MEDLINE, Web of Science, CINAHL and Scopus without restriction on year of publication. Quantitative, qualitative, and mixed-methods studies, as well as systematic reviews conducted in hospital-based emergency departments, were included that reported causes, consequences, or interventions related to ED overcrowding. Study selection and data extraction were performed by two reviewers independently, and methodological quality was assessed using CASP, Joanna Briggs Institute (JBI), and AMSTAR-2 tools. Due to substantial heterogeneity across studies, findings were synthesized narratively.
Results
From 3842 identified studies and175 full text reviews, a total of 63 studies met the inclusion criteria. ED overcrowding was driven primarily by access block related to inpatient bed shortages, delayed hospital discharges, inefficient patient flow, staffing constraints, and high volumes of non-urgent presentations. In LMIC settings, additional contributors included weak primary care systems and inadequate referral pathways. Overcrowding was consistently associated with delays in care, prolonged ED length of stay, adverse patient outcomes, increased healthcare provider burnout, and reduced system efficiency. Interventions targeting only the ED demonstrated limited effectiveness, whereas multicomponent hospital-wide and system-level strategies showed more sustained improvements.
Conclusion
Emergency department overcrowding is a complex, system-level problem with significant implications for patients, providers, and health systems. Evidence suggests that sustainable mitigation requires coordinated, multilevel interventions extending beyond the ED to the broader health system. Addressing ED overcrowding should be recognized as a priority for health system strengthening, particularly in resource-constrained settings.