title: Medication Use among Veterans across Health Care Systems.
abstract: Dual healthcare system use can create gaps and fragments of information for patient care. The Department of Veteran Affairs is implementing a health information exchange (HIE) program called the Virtual Lifetime Electronic Record (VLER), which allows providers to access and share information across healthcare systems. HIE has the potential to improve the safety of medication use. However, data regarding the pattern of outpatient medication use across systems of care is largely unknown. Therefore, the objective of this study is to describe the prevalence of medication dispensing across VA and non-VA health care systems among a cohort Veteran population.
  
  
  
  This study included all Veterans who had two outpatient visits or one inpatient visit at the Indianapolis VA during a 1-year period prior to VLER enrollment. Source of medication data was assessed at the subject level, and categorized as VA, INPC (non-VA), or both. The primary target was identification of sources for medication data. Then, we compared the mean number of prescriptions, as well as overall and pairwise differences in medication dispensing.
  
  
  
  Out of 52,444 Veterans, 17.4% of subjects had medication data available in a regional HIE. On average, 40 prescriptions per year were prescribed for Veterans who used both sources compared to 29 prescriptions per year from VA only and 25 prescriptions per year from INPC only sources. The annualized prescription rate of Veterans in the dual use group was 36% higher than those who had only VA data available and 61% higher than those who had only INPC data available.
  
  
  
  Our data demonstrated that 17.4% of subjects had medication use identified from non-VA sources, including prescriptions for antibiotics, antineoplastics, and anticoagulants. These data support the need for HIE programs to improve coordination of information, with the potential to reduce adverse medication interactions and improve medication safety.
authors.affiliation: Khoa A Nguyen, Pharm.D, Medical Informatics Postdoctoral Fellow, VA HSR&D-CHIC, D6004-2, 1481 West 10th Street, Indianapolis, IN 46202, USA, Email: khoa.nguyen6@va.gov, Phone: (317) 988-4409.
authors.forename: Khoa A
authors.initials: KA
authors.lastname: Nguyen
authors.forename: David A
authors.initials: DA
authors.lastname: Haggstrom
authors.forename: Susan
authors.initials: S
authors.lastname: Ofner
authors.forename: Susan M
authors.initials: SM
authors.lastname: Perkins
authors.forename: Dustin D
authors.initials: DD
authors.lastname: French
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Myers
authors.forename: Marc
authors.initials: M
authors.lastname: Rosenman
authors.forename: Michael
authors.initials: M
authors.lastname: Weiner
authors.forename: Brian E
authors.initials: BE
authors.lastname: Dixon
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Zillich
mesh_terms: D000328:Adult; D000368:Aged; D003695:Delivery of Health Care / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008509:Medication Systems; D008875:Middle Aged; D061214:Patient Safety; D011795:Surveys and Questionnaires; D014728:Veterans / Q000706:statistics & numerical data*
keywords: Medication use; dual health care systems; health information exchange; medication safety