title: Explaining accesses to electronic medical records using diagnosis information.
abstract: OBJECTIVE
  Ensuring the security and appropriate use of patient health information contained within electronic medical records systems is challenging. Observing these difficulties, we present an addition to the explanation-based auditing system (EBAS) that attempts to determine the clinical or operational reason why accesses occur to medical records based on patient diagnosis information. Accesses that can be explained with a reason are filtered so that the compliance officer has fewer suspicious accesses to review manually.
  
  
  METHODS
  Our hypothesis is that specific hospital employees are responsible for treating a given diagnosis. For example, Dr Carl accessed Alice's medical record because Hem/Onc employees are responsible for chemotherapy patients. We present metrics to determine which employees are responsible for a diagnosis and quantify their confidence. The auditing system attempts to use this responsibility information to determine the reason why an access occurred. We evaluate the auditing system's classification quality using data from the University of Michigan Health System.
  
  
  RESULTS
  The EBAS correctly determines which departments are responsible for a given diagnosis. Adding this responsibility information to the EBAS increases the number of first accesses explained by a factor of two over previous work and explains over 94% of all accesses with high precision.
  
  
  CONCLUSIONS
  The EBAS serves as a complementary security tool for personal health information. It filters a majority of accesses such that it is more feasible for a compliance officer to review the remaining suspicious accesses manually.
authors.affiliation: Electrical Engineering & Computer Science, University of Michigan, Ann Arbor, MI 48109, USA. dfabbri@umich.edu
authors.forename: Daniel
authors.initials: D
authors.lastname: Fabbri
authors.forename: Kristen
authors.initials: K
authors.lastname: Lefevre
mesh_terms: D016494:Computer Security; D003219:Confidentiality; D057286:Electronic Health Records; D019983:Guideline Adherence; D006751:Hospital Information Systems; D006801:Humans; D008330:Management Audit / Q000379:methods*; D008824:Michigan