title: Combining surveillance systems: effective merging of U.S. Veteran and military health data.
abstract: BACKGROUND
  The U.S. Department of Veterans Affairs (VA) and Department of Defense (DoD) had more than 18 million healthcare beneficiaries in 2011. Both Departments conduct individual surveillance for disease events and health threats.
  
  
  METHODS
  We performed joint and separate analyses of VA and DoD outpatient visit data from October 2006 through September 2010 to demonstrate geographic and demographic coverage, timeliness of influenza epidemic awareness, and impact on spatial cluster detection achieved from a joint VA and DoD biosurveillance platform.
  
  
  RESULTS
  Although VA coverage is greater, DoD visit volume is comparable or greater. Detection of outbreaks was better in DoD data for 58% and 75% of geographic areas surveyed for seasonal and pandemic influenza, respectively, and better in VA data for 34% and 15%. The VA system tended to alert earlier with a typical H3N2 seasonal influenza affecting older patients, and the DoD performed better during the H1N1 pandemic which affected younger patients more than normal influenza seasons. Retrospective analysis of known outbreaks demonstrated clustering evidence found in separate DoD and VA runs, which persisted with combined data sets.
  
  
  CONCLUSIONS
  The analyses demonstrate two complementary surveillance systems with evident benefits for the national health picture. Relative timeliness of reporting could be improved in 92% of geographic areas with access to both systems, and more information provided in areas where only one type of facility exists. Combining DoD and VA data enhances geographic cluster detection capability without loss of sensitivity to events isolated in either population and has a manageable effect on customary alert rates.
authors.affiliation: Armed Forces Health Surveillance Center, US Department of Defense, Silver Spring, Maryland, United States of America.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Pavlin
authors.affiliation: Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland, United States of America.
authors.forename: Howard S
authors.initials: HS
authors.lastname: Burkom
authors.affiliation: Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland, United States of America.
authors.forename: Yevgeniy
authors.initials: Y
authors.lastname: Elbert
authors.affiliation: Office of Public Health, US Department of Veterans Affairs, Washington, District of Columbia, United States of America.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Lucero-Obusan
authors.affiliation: Office of Public Health, US Department of Veterans Affairs, Washington, District of Columbia, United States of America.
authors.forename: Carla A
authors.initials: CA
authors.lastname: Winston
authors.affiliation: US Army Institute of Public Health, US Department of Defense, Aberdeen Proving Ground, Maryland, United States of America.
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Cox
authors.affiliation: Office of Public Health, US Department of Veterans Affairs, Washington, District of Columbia, United States of America.
authors.forename: Gina
authors.initials: G
authors.lastname: Oda
authors.affiliation: Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland, United States of America.
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Lombardo
authors.affiliation: Office of Public Health, US Department of Veterans Affairs, Washington, District of Columbia, United States of America.
authors.forename: Mark
authors.initials: M
authors.lastname: Holodniy
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D055877:Biosurveillance; D002648:Child; D002675:Child, Preschool; D057225:Data Mining / Q000379:methods*; D016208:Databases, Factual; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000502:physiology; D053122:Influenza A Virus, H3N2 Subtype / Q000502:physiology; D007251:Influenza, Human / Q000453:epidemiology; D008875:Middle Aged; D058873:Pandemics / Q000706:statistics & numerical data; D062486:Public Health Surveillance; D012189:Retrospective Studies; D013997:Time Factors; D014481:United States; D059030:United States Department of Defense / Q000706:statistics & numerical data; D014493:United States Department of Veterans Affairs / Q000706:statistics & numerical data; D014728:Veterans / Q000706:statistics & numerical data*; D058014:Veterans Health / Q000706:statistics & numerical data*; D055815:Young Adult