title: Improving survey methods in sero-epidemiological studies of injecting drug users: a case example of two cross sectional surveys in Serbia and Montenegro.
abstract: BACKGROUND
  Little is known about the prevalence of HIV or HCV in injecting drug users (IDUs) in Serbia and Montenegro. We measured prevalence of antibodies to HIV (anti-HIV) and hepatitis C virus (anti-HCV), and risk factors for anti-HCV, in community-recruited IDUs in Belgrade and Podgorica, and determined the performance of a parallel rapid HIV testing algorithm.
  
  
  METHODS
  Respondent driven sampling and audio-computer assisted survey interviewing (ACASI) methods were employed. Dried blood spots were collected for unlinked anonymous antibody testing. Belgrade IDUs were offered voluntary confidential rapid HIV testing using a parallel testing algorithm, the performance of which was compared with standard laboratory tests. Predictors of anti-HCV positivity and the diagnostic accuracy of the rapid HIV test algorithm were calculated.
  
  
  RESULTS
  Overall population prevalence of anti-HIV and anti-HCV in IDUs were 3% and 63% respectively in Belgrade (n = 433) and 0% and 22% in Podgorica (n = 328). Around a quarter of IDUs in each city had injected with used needles and syringes in the last four weeks. In both cities anti-HCV positivity was associated with increasing number of years injecting (eg Belgrade adjusted odds ratio (AOR) 5.6 (95% CI 3.2-9.7) and Podgorica AOR 2.5 (1.3-5.1) for >or= 10 years v 0-4 years), daily injecting (Belgrade AOR 1.6 (1.0-2.7), Podgorica AOR 2.1 (1.3-5.1)), and having ever shared used needles/syringes (Belgrade AOR 2.3 (1.0-5.4), Podgorica AOR 1.9 (1.4-2.6)). Half (47%) of Belgrade participants accepted rapid HIV testing, and there was complete concordance between rapid test results and subsequent confirmatory laboratory tests (sensitivity 100% (95%CI 59%-100%), specificity 100% (95%CI 98%-100%)).
  
  
  CONCLUSIONS
  The combination of community recruitment, ACASI, rapid testing and a linked diagnostic accuracy study provide enhanced methods for conducting blood borne virus sero-prevalence studies in IDUs. The relatively high uptake of rapid testing suggests that introducing this method in community settings could increase the number of people tested in high risk populations. The high prevalence of HCV and relatively high prevalence of injecting risk behaviour indicate that further HIV transmission is likely in IDUs in both cities. Urgent scale up of HIV prevention interventions is needed.
authors.affiliation: MRC Clinical Trials Unit, London, UK. a.judd@ctu.mrc.ac.uk
authors.forename: Ali
authors.initials: A
authors.lastname: Judd
authors.forename: Tim
authors.initials: T
authors.lastname: Rhodes
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Johnston
authors.forename: Lucy
authors.initials: L
authors.lastname: Platt
authors.forename: Violeta
authors.initials: V
authors.lastname: Andjelkovic
authors.forename: Danijela
authors.initials: D
authors.lastname: Simić
authors.forename: Boban
authors.initials: B
authors.lastname: Mugosa
authors.forename: Milena
authors.initials: M
authors.lastname: Simić
authors.forename: Sonja
authors.initials: S
authors.lastname: Zerjav
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Parry
authors.forename: John V
authors.initials: JV
authors.lastname: Parry
mesh_terms: D015492:AIDS Serodiagnosis; D000328:Adult; D035041:Anonymous Testing; D003430:Cross-Sectional Studies; D055030:Drug Users; D005260:Female; D015658:HIV Infections / Q000453:epidemiology; D015528:HIV Seroprevalence; D006306:Health Surveys; D006526:Hepatitis C / Q000453:epidemiology; D018937:Hepatitis C Antibodies / Q000097:blood; D006801:Humans; D008297:Male; D054548:Montenegro / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D055771:Serbia / Q000453:epidemiology; D015819:Substance Abuse, Intravenous / Q000453:epidemiology*
chemical_list: D018937:Hepatitis C Antibodies