title: Emergency department reliance: a discriminatory measure of frequent emergency department users.
abstract: OBJECTIVE
  High emergency department (ED) use has previously been defined as a person's having a large number of ED visits, implying that all frequent users are the same. ED reliance (EDR), the percentage of all health care visits that occur in the ED, considers ED use in relation to primary care use and, thus, may discriminate among high-ED-user populations. Our objective was to determine whether EDR, as a complementary use measure, could differentiate frequent users secondary to increased need for care from those with access issues.
  
  
  METHODS
  We conducted an analysis of prospectively collected data from the Medical Expenditure Panel Survey from 2000-2001 and 2001-2002. Frequent ED users were defined as having >or=2 ED visits, and EDR was dichotomized as high (>0.33) or low (<or=0.33). Odds of being a frequent user or having high EDR were analyzed by using logistic regression.
  
  
  RESULTS
  A total of 8823 children were included. Within frequent-ED-use populations, young children and children with special health care needs were less likely (odds ratio: 0.55 and 0.72, respectively) to have high EDR, whereas those with lower education, low income, and public insurance and those of black race were more likely to have high EDR.
  
  
  CONCLUSIONS
  EDR is a readily available measure in large administrative databases that discriminates among frequent-user populations, differentiating increased need for ED services from lack of access to quality primary care.
authors.affiliation: Section of Emergency Medicine, Department of Pediatrics, Children's Research Institute, Milwaukee, Wisconsin 53226, USA. ekroner@mcw.edu
authors.forename: Eric L
authors.initials: EL
authors.lastname: Kroner
authors.forename: Raymond G
authors.initials: RG
authors.lastname: Hoffmann
authors.forename: David C
authors.initials: DC
authors.lastname: Brousseau
mesh_terms: D000293:Adolescent; D002648:Child; D002662:Child Health Services / Q000706:statistics & numerical data*; D002675:Child, Preschool; D016001:Confidence Intervals; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D019538:Health Care Surveys; D054625:Healthcare Disparities; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D017057:Medically Uninsured / Q000706:statistics & numerical data; D020380:Needs Assessment; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D011203:Poverty; D011336:Probability; D011446:Prospective Studies; D018570:Risk Assessment; D012959:Socioeconomic Factors; D014481:United States