title: Does lack of a usual source of care or health insurance increase the likelihood of an emergency department visit? Results of a national population-based study.
abstract: OBJECTIVE
  We determined whether having a usual source of care or health insurance is associated with the likelihood of an emergency department (ED) visit.
  
  
  METHODS
  This was a multivariate analysis of the 2000 to 2001 nationally representative Community Tracking Study Household Survey to assess the independent association of usual source of care, health insurance, income, and health status with the likelihood of making 1 or more ED visits in the previous year.
  
  
  RESULTS
  Based on a sample of 49,603 adults, an estimated 45.3 million adults reported 79.6 million ED visits in the previous year; 83.1% of these visitors identified a usual source of care other than an ED. Persons with poor physical health status made 48.4% of visits. Adults without a usual source of care were less likely to have had an ED visit than those whose usual source of care was a private physician (odds ratio [OR] 0.75). Uninsured individuals were no more likely to have an ED visit than insured individuals. Poor physical health (OR 2.41), poor mental health (OR 1.51), 5 or more outpatient visits during the year (OR 4.05), and changes in insurance coverage (OR 1.14) or usual source of care (OR 1.32) during the year were associated with an ED visit. Enrollment in a health maintenance organization and satisfaction with one's physician were not independently associated with ED use.
  
  
  CONCLUSIONS
  ED users are similar to nonusers with regard to health insurance and usual source of care but are more likely to be in poor health and have experienced disruptions in regular care. The success of efforts to decrease ED use may depend on improving delivery of outpatient care.
authors.affiliation: Division of Emergency Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143-0208, USA. weber@medicine.ucsf.edu
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Weber
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Showstack
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Hunt
authors.forename: David C
authors.initials: DC
authors.lastname: Colby
authors.forename: Michael L
authors.initials: ML
authors.lastname: Callaham
mesh_terms: D000328:Adult; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D019538:Health Care Surveys; D006297:Health Services Accessibility / Q000706:statistics & numerical data*; D006304:Health Status; D006801:Humans; D007182:Income; D016015:Logistic Models; D017057:Medically Uninsured / Q000706:statistics & numerical data*; D016017:Odds Ratio; D014481:United States