title: Health information exchange usage in emergency departments and clinics: the who, what, and why.
abstract: OBJECTIVE
  Health information exchange (HIE) systems are being developed across the nation. Understanding approaches taken by existing successful exchanges can help new exchange efforts determine goals and plan implementations. The goal of this study was to explore characteristics of use and users of a successful regional HIE.
  
  
  METHODS
  We used a mixed-method analysis, consisting of cross-sectional audit log data, semi-structured interviews, and direct observation in a sample of emergency departments and ambulatory safety net clinics actively using HIE. For each site, we measured overall usage trends, user logon statistics, and data types accessed by users. We also assessed reasons for use and outcomes of use.
  
  
  RESULTS
  Overall, users accessed HIE for 6.8% of all encounters, with higher rates of access for repeat visits, for patients with comorbidities, for patients known to have data in the exchange, and at sites providing HIE access to both nurses and physicians. Discharge summaries and test reports were the most frequently accessed data in the exchange. Providers consistently noted retrieving additional history, preventing repeat tests, comparing new results to retrieved results, and avoiding hospitalizations as a consequence of HIE access.
  
  
  CONCLUSIONS
  HIE use in emergency departments and ambulatory clinics was focused on patients where missing information was believed to be present in the exchange and was related to factors including the roles of people with access, the setting, and other site-specific issues that impacted the overall breadth of routine system use. These data should form an important foundation as other sites embark upon HIE implementation.
authors.affiliation: Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA. kevin.johnson@vanderbilt.edu
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Johnson
authors.forename: Kim M
authors.initials: KM
authors.lastname: Unertl
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Chen
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Lorenzi
authors.forename: Hui
authors.initials: H
authors.lastname: Nian
authors.forename: James
authors.initials: J
authors.lastname: Bailey
authors.forename: Mark
authors.initials: M
authors.lastname: Frisse
mesh_terms: D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D057286:Electronic Health Records / Q000706:statistics & numerical data*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D006801:Humans; D033181:Information Dissemination; D008498:Medical Record Linkage; D015397:Program Evaluation; D013714:Tennessee