title: Characteristics of frequent users of the emergency department in the general adult population: A systematic review of international healthcare systems.
abstract: OBJECTIVE
  The objectives of this study were to synthesize and compare population characteristics associated with frequent emergency department (ED) use within and across healthcare systems.
  
  
  METHODS
  A systematic review of literature published between 1950 and 2015 was conducted. Healthcare systems of included studies were categorized using the Rothgang-Wendt typology. Demographic, clinical and health service utilization characteristics of frequent ED users in the general adult population were identified within each healthcare system. Pooled estimates, stratified by healthcare system, were calculated to compare the association of each characteristic with frequent, compared to non-frequent, emergency room use.
  
  
  RESULTS
  Twenty moderate to high quality comparative cohort studies were included. Among these, five healthcare systems were identified: National Health Insurance; Private Healthcare; National Health Service; Social Health Insurance and Etatist Social Health Insurance. Many similar characteristics were observed: in most healthcare systems, frequent ED users were more likely to be older, female, and have a mental health diagnosis. Previous hospitalizations and high primary care use (>3 visits/year) were associated with future frequent ED use in the NHIS and NHS systems.
  
  
  CONCLUSIONS
  Observed similarities suggest that frequent ED use may not differ from one healthcare system to the next. With increasing need to develop solutions for high ED utilization world-wide, targeted efforts must be made to bolster dissemination and uptake of effective interventions across healthcare contexts.
authors.affiliation: The Department Community Health Sciences, University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada; O'Brien Institute for Public Health University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
authors.forename: Lesley J J
authors.initials: LJ
authors.lastname: Soril
authors.affiliation: The Department Community Health Sciences, University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada; O'Brien Institute for Public Health University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Leggett
authors.affiliation: The Department Community Health Sciences, University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada; Institute of Health Economics, 1200, 10405 Jasper Avenue, Edmonton, AB T5J-3N4, Canada.
authors.forename: Diane L
authors.initials: DL
authors.lastname: Lorenzetti
authors.affiliation: The Department Community Health Sciences, University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada; O'Brien Institute for Public Health University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
authors.forename: Tom W
authors.initials: TW
authors.lastname: Noseworthy
authors.affiliation: The Department Community Health Sciences, University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada; O'Brien Institute for Public Health University of Calgary, Teaching Research and Wellness Building, 3280 Hospital Drive NW, Calgary, AB T2N 4N1, Canada. Electronic address: fclement@ucalgary.ca.
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Clement
mesh_terms: D003710:Demography; D004636:Emergency Service, Hospital / Q000191:economics / Q000706:statistics & numerical data*; D014943:Global Health; D017048:Health Care Costs; D006760:Hospitalization; D006801:Humans; D007348:Insurance, Health / Q000191:economics; D000069342:Medical Overuse / Q000191:economics*
keywords: Emergency department; Frequent users; Health policy development; High users, high needs