title: A population-based study of the association between socioeconomic status and emergency department utilization in Ontario, Canada.
abstract: OBJECTIVE
  The relative effects of socioeconomic status (SES) and health status on emergency department (ED) utilization are controversial. The authors examined this in a setting with universal health coverage.
  
  
  METHODS
  For Ontario participants age 20-74 years, Canadian Community Health Survey 2000 to 2001 responses were linked to Ontario Health Insurance Plan (OHIP) physician utilization data for 1999 to 2001 and the National Ambulatory Care Reporting System (NACRS) for ED utilization in 2002. SES was defined primarily according to high school completion and secondarily according to income. The primary outcome was less urgent ED visit, defined as Canadian Triage and Acuity Scale (CTAS) 4 or 5 and not admitted to hospital.
  
  
  RESULTS
  The weighted sample was 9,323,217. Overall, 31.4% of the sample used an Ontario ED in 2002. The majority of visits (59.1%) were classified as less urgent. Fair or poor self-perceived health was the largest predictor of ED use, regardless of visit urgency. Respondents with low education were more likely to have both less urgent visits (odds ratio [OR] = 1.65, 95% confidence interval [CI] = 1.35 to 1.94) and more urgent visits (OR = 1.39, 95% CI = 1.09 to 1.68) after controlling for age, sex, income, self-perceived health, urban or rural location, regular doctor, and non-ED physician visits. Education was not associated with having less urgent versus more urgent visits (OR = 0.92, 95% CI = 0.68 to 1.14).
  
  
  CONCLUSIONS
  In a setting with universal health insurance, worse health status is the largest predictor of ED utilization, but low SES is independently associated with increased use of the ED, regardless of visit urgency. This study lends support to findings in other health systems that those using EDs are more ill and more disadvantaged.
authors.affiliation: Division of Emergency Medicine, Department of Medicine, the Dalla Lana School of Public Health, University of Toronto, Ontario, Canada. yasmin.khan@uhn.on.ca
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Khan
authors.forename: Richard H
authors.initials: RH
authors.lastname: Glazier
authors.forename: Rahim
authors.initials: R
authors.lastname: Moineddin
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Schull
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease / Q000628:therapy; D016208:Databases, Factual; D004630:Emergencies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D009864:Ontario; D012044:Regression Analysis; D012720:Severity of Illness Index; D012959:Socioeconomic Factors; D014218:Triage / Q000706:statistics & numerical data; D019472:Universal Health Insurance; D055815:Young Adult