title: Deriving measures of intensive care unit antimicrobial use from computerized pharmacy data: methods, validation, and overcoming barriers.
abstract: OBJECTIVE
  To outline methods for deriving and validating intensive care unit (ICU) antimicrobial utilization (AU) measures from computerized data and to describe programming problems that emerged.
  
  
  METHODS
  Retrospective evaluation of computerized pharmacy and administrative data.
  
  
  METHODS
  ICUs from 4 academic medical centers over 36 months.
  
  
  METHODS
  Investigators separately developed and validated programming code to report AU measures in selected ICUs. Use of antibacterial and antifungal drugs for systemic administration was categorized and expressed as antimicrobial-days (each day that each antimicrobial drug was given to each patient) and patient-days receiving antimicrobials (each day that any antimicrobial drug was given to each patient). Monthly rates were compiled and analyzed centrally, with ICU patient-days as the denominator. Results were validated against data collected from manual review of medical records. Frequent discussion among investigators aided identification and correction of programming problems.
  
  
  RESULTS
  AU data were successfully programmed though a reiterative process of computer code revision. After identifying and resolving major programming errors, comparison of computerized patient-level data with data collected by manual review of medical records revealed discrepancies in antimicrobial-days and patient-days receiving antimicrobials that ranged from less than 1% to 17.7%. The hospital from which numerator data were derived from electronic records of medication administration had the least discrepant results.
  
  
  CONCLUSIONS
  Computerized AU measures can be derived feasibly, but threats to validity must be sought out and corrected. The magnitude of discrepancies between computerized AU data and a gold standard based on manual review of medical records varies, with electronic records of medication administration providing maximal accuracy.
authors.affiliation: Division of Infectious Diseases, John H. Stroger, Jr. Hospital of Cook County, Rush Medical College, Chicago, Illinois, USA. david.schwartz@hektoen.org
authors.forename: David N
authors.initials: DN
authors.lastname: Schwartz
authors.forename: R Scott
authors.initials: RS
authors.lastname: Evans
authors.forename: Bernard C
authors.initials: BC
authors.lastname: Camins
authors.forename: Yosef M
authors.initials: YM
authors.lastname: Khan
authors.forename: James F
authors.initials: JF
authors.lastname: Lloyd
authors.forename: Nadine
authors.initials: N
authors.lastname: Shehab
authors.forename: Kurt
authors.initials: K
authors.lastname: Stevenson
mesh_terms: D000046:Academic Medical Centers; D000890:Anti-Infective Agents / Q000627:therapeutic use*; D016303:Clinical Pharmacy Information Systems; D017723:Drug Utilization Review / Q000379:methods*; D006801:Humans; D007362:Intensive Care Units; D008499:Medical Records; D016347:Medical Records Systems, Computerized; D010607:Pharmacy Service, Hospital; D012189:Retrospective Studies; D012984:Software
chemical_list: D000890:Anti-Infective Agents