title: Hepatitis C tested prevalence and comorbidities among veterans in the US Northwest.
abstract: OBJECTIVE
  (1) Investigate the epidemiology of hepatitis C virus infection among patients seen in the Veterans Administration Northwest Network; (2) examine time trends in testing practices and results; and (3) estimate the prevalence of hepatitis C virus infection among active patients.
  
  
  BACKGROUND
  Hepatitis C virus infection causes chronic hepatitis and cirrhosis and is a leading cause of end-stage liver disease. Hepatitis C virus antibodies are estimated to be present in 1.8% of the US population, but reports of its prevalence among US veterans range from 1.7 to 35%.
  
  
  METHODS
  Retrospective review of computerized medical records of veterans tested for hepatitis C from October 1994 through December 2000 (n = 37,938) at 8 Northwest Veterans Administration Medical Centers.
  
  
  RESULTS
  Among tested veterans, 8230 (21.7%) had evidence of hepatitis C virus infection. The number of patients tested increased annually from 2335 to 18,191, while the proportion with first-time positive hepatitis C test results decreased from 35 to 10%. This drop in tested prevalence was associated with a shift away from testing individuals at highest risk--those with positive hepatitis B serostatus, repeatedly elevated alanine transaminase levels, and drug use disorder diagnoses. We estimate that 11.4% of the Northwest Network veteran users are hepatitis C virus seropositive, with a lower bound of 4.0% and upper bound of 19.5%.
  
  
  CONCLUSIONS
  Although estimates of hepatitis C virus infection rates among veteran users of the Veterans Administration system remain higher than those for the general population, changes in testing practice make generalizations from earlier studies hazardous.
authors.affiliation: Veterans Affairs Puget Sound Health Care System, Mental Health Service and the Addictions Treatment Center, Seattle, WA 98108, USA. Kevin.Sloan@med.va.gov
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Sloan
authors.forename: Kristy A
authors.initials: KA
authors.lastname: Straits-Tröster
authors.forename: Jason A
authors.initials: JA
authors.lastname: Dominitz
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Kivlahan
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D005260:Female; D006526:Hepatitis C / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015205:Northwestern United States / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D014728:Veterans / Q000706:statistics & numerical data*