title: High utilizers of emergency health services in a population-based cohort of homeless adults.
abstract: OBJECTIVE
  We identified predictors of emergency department (ED) use among a population-based prospective cohort of homeless adults in Toronto, Ontario.
  
  
  METHODS
  We assessed ED visit rates using administrative data from the Institute for Clinical Evaluative Sciences (2005-2009). We then used logistic regression to identify predictors of ED use. Frequent users were defined as participants with rates in the top decile (≥ 4.7 visits per person-year).
  
  
  RESULTS
  Among 1165 homeless adults, 892 (77%) had at least 1 ED visit during the study. The average rate of ED visits was 2.0 visits per person-year, whereas frequent users averaged 12.1 visits per person-year. Frequent users accounted for 10% of the sample but contributed more than 60% of visits. Predictors of frequent use in adjusted analyses included birth in Canada, higher monthly income, lower health status, perceived unmet mental health needs, and perceived external health locus of control from powerful others; being accompanied by a partner or dependent children had a protective effect on frequent use.
  
  
  CONCLUSIONS
  Among homeless adults with universal health insurance, a small subgroup accounted for the majority of visits to emergency services. Frequent use was driven by multiple predisposing, enabling, and need factors.
authors.affiliation: Catharine Chambers, Shirley Chiu, and Stephen W. Hwang are with the Centre for Research on Inner City Health, the Keenan Research Centre, Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, Ontario. Marko Katic and Alex Kiss are with the Department of Research Design and Biostatistics, Sunnybrook Health Sciences Centre, Toronto. Donald A. Redelmeier is with the Institute for Clinical Evaluative Sciences, Sunnybrook Health Sciences Centre, Toronto. Wendy Levinson is with the Department of Medicine, University of Toronto, Toronto.
authors.forename: Catharine
authors.initials: C
authors.lastname: Chambers
authors.forename: Shirley
authors.initials: S
authors.lastname: Chiu
authors.forename: Marko
authors.initials: M
authors.lastname: Katic
authors.forename: Alex
authors.initials: A
authors.lastname: Kiss
authors.forename: Donald A
authors.initials: DA
authors.lastname: Redelmeier
authors.forename: Wendy
authors.initials: W
authors.lastname: Levinson
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Hwang
mesh_terms: D000328:Adult; D000367:Age Factors; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006304:Health Status; D006703:Ill-Housed Persons / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D012307:Risk Factors; D012737:Sex Factors; D012944:Social Support; D012959:Socioeconomic Factors