title: Opiate substitution treatment and HIV transmission in people who inject drugs: systematic review and meta-analysis.
abstract: OBJECTIVE
  To quantify the effect of opiate substitution treatment in relation to HIV transmission among people who inject drugs.
  
  
  METHODS
  Systematic review and meta-analysis of prospective published and unpublished observational studies.
  
  
  METHODS
  Search of Medline, Embase, PsychINFO, and the Cochrane Library from the earliest year to 2011 without language restriction.
  
  
  METHODS
  We selected studies that directly assessed the impact of opiate substitution treatment in relation to incidence of HIV and studies that assessed incidence of HIV in people who inject drugs and that might have collected data regarding exposure to opiate substitution treatment but not have reported it. Authors of these studies were contacted. Data were extracted by two reviewers and pooled in a meta-analysis with a random effects model.
  
  
  RESULTS
  Twelve published studies that examined the impact of opiate substitution treatment on HIV transmission met criteria for inclusion, and unpublished data were obtained from three additional studies. All included studies examined methadone maintenance treatment. Data from nine of these studies could be pooled, including 819 incident HIV infections over 23,608 person years of follow-up. Opiate substitution treatment was associated with a 54% reduction in risk of HIV infection among people who inject drugs (rate ratio 0.46, 95% confidence interval 0.32 to 0.67; P<0.001). There was evidence of heterogeneity between studies (I(2)=60%, χ(2)=20.12, P=0.010), which could not be explained by geographical region, site of recruitment, or the provision of incentives. There was weak evidence for greater benefit associated with longer duration of exposure to opiate substitution treatment.
  
  
  CONCLUSIONS
  Opiate substitution treatment provided as maintenance therapy is associated with a reduction in the risk of HIV infection among people who inject drugs. These findings, however, could reflect comparatively high levels of motivation to change behaviour and reduce injecting risk behaviour among people who inject drugs who are receiving opiate substitution treatment.
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol BS8 2PS, UK.
authors.forename: Georgie J
authors.initials: GJ
authors.lastname: MacArthur
authors.forename: Silvia
authors.initials: S
authors.lastname: Minozzi
authors.forename: Natasha
authors.initials: N
authors.lastname: Martin
authors.forename: Peter
authors.initials: P
authors.lastname: Vickerman
authors.forename: Sherry
authors.initials: S
authors.lastname: Deren
authors.forename: Julie
authors.initials: J
authors.lastname: Bruneau
authors.forename: Louisa
authors.initials: L
authors.lastname: Degenhardt
authors.forename: Matthew
authors.initials: M
authors.lastname: Hickman
mesh_terms: D015986:Confounding Factors, Epidemiologic; D018562:Disease Transmission, Infectious / Q000517:prevention & control / Q000706:statistics & numerical data; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission*; D006801:Humans; D008691:Methadone / Q000008:administration & dosage*; D009294:Narcotics / Q000008:administration & dosage*; D058850:Opiate Substitution Treatment / Q000379:methods; D011322:Primary Prevention / Q000379:methods; D011446:Prospective Studies; D012107:Research Design; D012307:Risk Factors; D015819:Substance Abuse, Intravenous / Q000150:complications* / Q000188:drug therapy*; D013997:Time Factors
chemical_list: D009294:Narcotics; D008691:Methadone