title: Identifying frequent users of emergency department resources.
abstract: BACKGROUND
  There is growing focus on frequent users of acute care resources. If these patients can be identified, interventions can be established to offer more consistent management plans to decrease inappropriate utilization.
  
  
  OBJECTIVE
  To compare a hospital-specific approach with a region-wide approach to identify frequent Emergency Department (ED) users.
  
  
  METHODS
  A retrospective multi-center cohort study of hospital ED visits from all 18 nonmilitary, acute care hospitals serving the San Diego region (population 3.2 million) between 2008 and 2010 using data submitted to the California Office of Statewide Health Planning and Development. Frequent users and super users were defined as having 6 to 20 and 21 or more visits, respectively, during any consecutive 12 months in the study period. Comparisons between community-wide and hospital-specific methods were made.
  
  
  RESULTS
  There were 925,719 individual patients seen in an ED, resulting in 2,016,537 total visits. There were 28,569 patients identified as frequent users and 1661 identified as super users, using a community-wide approach. Individual hospitals could identify 15.6% to 62.4% of all frequent users, and from 0.3% to 15.2% of all the super users who visited their facility. Overall, the hospital-specific approach identified 20,314 frequent users and 571 super users, failing to identify 28.9% of frequent users and 65.6% of super users visiting San Diego County EDs that would otherwise have been identified using a community-wide approach.
  
  
  CONCLUSIONS
  A community-wide identification method resulted in greater numbers of individuals being identified as frequent and super ED users than when utilizing individual hospital data.
authors.affiliation: Department of Emergency Medicine, University of California, San Diego, San Diego, California.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Castillo
authors.affiliation: Department of Emergency Medicine, University of California, San Diego, San Diego, California.
authors.forename: Jesse J
authors.initials: JJ
authors.lastname: Brennan
authors.affiliation: Department of Emergency Medicine, University of California, San Diego, San Diego, California.
authors.forename: James P
authors.initials: JP
authors.lastname: Killeen
authors.affiliation: Department of Emergency Medicine, University of California, San Diego, San Diego, California.
authors.forename: Theodore C
authors.initials: TC
authors.lastname: Chan
mesh_terms: D000328:Adult; D002140:California; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006786:Hospitals, Urban / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D012189:Retrospective Studies
keywords: emergency department; health information exchange; health resources