title: Are the uninsured responsible for the increase in emergency department visits in the United States?
abstract: OBJECTIVE
  The rise in emergency department (ED) use in the United States is frequently attributed to increased visits by the uninsured. We determine whether insurance status is associated with the increase in ED visits.
  
  
  METHODS
  Using the national Community Tracking Study Household Surveys from 1996 to 1997, 1998 to 1999, 2000 to 2001, and 2003 to 2004, we determined for each period the proportion of reported adult ED visits according to insurance status, family income, usual source of care, health status, and outpatient (non-ED) visits. Trends over time were tested for statistical significance.
  
  
  RESULTS
  The proportion of adult ED visits by persons without insurance was stable across the decade. Uninsured individuals accounted for 15.5% of ED visits in 1996 to 1997, 16.1% in 1998 to 1999, 15.2% in 2000 to 2001, and 14.5% of visits in 2003 to 2004 (P for trend=.43). The proportion of visits by persons whose family income was greater than 400% of the federal poverty level increased from 21.9% to 29.0% (P=.002). The proportion of visits by those whose usual source of care was a physician's office increased from 52.4% in 1996 to 1997 to 59.0% in 2003 to 2004 (P=.002), whereas the proportion of visits by those without a usual source of care was essentially unchanged (9.7% of visits in 1996 to 1997 and 9.6% in 2003 to 2004; P=.74).
  
  
  CONCLUSIONS
  The rise in ED visits between 1996 and 2003 cannot be primarily attributed to the uninsured. Major contributors to increasing ED utilization appear to be disproportionate increases in use by nonpoor persons and by persons whose usual source of care is a physician's office.
authors.affiliation: Division of Emergency Medicine, School 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: Barbara
authors.initials: B
authors.lastname: Grimes
authors.forename: Peter
authors.initials: P
authors.lastname: Bacchetti
authors.forename: Michael L
authors.initials: ML
authors.lastname: Callaham
mesh_terms: D000328:Adult; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data* / Q000639:trends; D019538:Health Care Surveys; D006304:Health Status; D006801:Humans; D007182:Income; D019458:Insurance Coverage; D017057:Medically Uninsured / Q000706:statistics & numerical data*; D014481:United States