title: Ascertainment of warfarin and aspirin use by medical record review compared with automated pharmacy data.
abstract: OBJECTIVE
  Automated pharmacy databases are increasingly available for assessing medication use, but research on the validity of these data is incomplete. This study aimed to measure agreement on warfarin and aspirin use between medical records and automated pharmacy data among patients with newly detected atrial fibrillation (AF).
  
  
  METHODS
  Patients with newly detected AF (n = 1953) were previously identified in a cohort study at Group Health (GH) in Washington State. Medical records were reviewed for information on risk factors and medication use, as well as clinical care during the 6 months after AF onset. Medication data were also obtained from the GH pharmacy database. We determined the sensitivity, specificity, and positive predictive value (PPV) as measures of the validity of the GH pharmacy database as compared with medical records for warfarin and aspirin use during the first 6 and 3 months after AF onset. We also calculated the κ statistic.
  
  
  RESULTS
  For warfarin use, in comparison with the medical record review, the sensitivity, specificity, and PPV for the GH pharmacy database were excellent, and agreement was almost perfect in the 3- and 6-month periods after AF onset (κ = 0.92 and 0.93, respectively). For aspirin use, the GH pharmacy database had low sensitivity but high specificity, and agreement was only fair for these two periods (κ = 0.28 and 0.31, respectively).
  
  
  CONCLUSIONS
  The GH pharmacy database is a valuable source of data for pharmacoepidemiologic research on warfarin use among patients with AF. However, the database cannot be recommended for assessment of aspirin use. Copyright © 2010 John Wiley & Sons, Ltd.
authors.affiliation: Department of Epidemiology, University of Washington, Seattle, WA 98101-1448, USA. rkgarg@u.washington.edu
authors.forename: Renu K
authors.initials: RK
authors.lastname: Garg
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Glazer
authors.forename: Kerri L
authors.initials: KL
authors.lastname: Wiggins
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Newton
authors.forename: Evan L
authors.initials: EL
authors.lastname: Thacker
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Smith
authors.forename: David S
authors.initials: DS
authors.lastname: Siscovick
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Psaty
authors.forename: Susan R
authors.initials: SR
authors.lastname: Heckbert
mesh_terms: D000368:Aged; D001241:Aspirin / Q000008:administration & dosage* / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000453:epidemiology; D015331:Cohort Studies; D003157:Community Pharmacy Services / Q000706:statistics & numerical data*; D016208:Databases, Factual / Q000706:statistics & numerical data*; D017723:Drug Utilization Review / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008499:Medical Records / Q000706:statistics & numerical data; D016347:Medical Records Systems, Computerized / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014859:Warfarin / Q000008:administration & dosage* / Q000627:therapeutic use; D014861:Washington
chemical_list: D014859:Warfarin; D001241:Aspirin