title: The validity of reporting willingness to use a supervised injecting facility on subsequent program use among people who use injection drugs.
abstract: BACKGROUND
  Innovative health programs for injection drug users (IDUs), such as supervised injecting facilities (SIFs), are often preceded by evaluations of IDUs' willingness to use the service. The validity of these surveys has not been fully evaluated. We sought to determine whether measures of willingness collected prior to the opening of a Canadian SIF accurately predicted subsequent use of the program.
  
  
  METHODS
  Data were derived from a prospective cohort of IDUs. The sample size for this study was 640 IDUs. Using multivariate logistic regression, it was assessed if a history of reporting willingness to use the program, were it available, was associated with subsequent use. In sub-analysis restricted to individuals who had a history of reported willingness, we used multivariate longitudinal analysis to identify factors associated with not attending the SIF.
  
  
  RESULTS
  Among 442 IDUs, 72% of those who reported initial willingness to use a SIF later attended the program, and a prior willingness to use a SIF significantly predicted later attendance (adjusted odds ratio = 1.67). In sub-analyses restricted to those who had a history of reporting willingness to use the SIF, not using the program was predicted by not frequenting the neighborhood where the SIF was located.
  
  
  CONCLUSIONS
  Our findings indicate that reported willingness measures collected from IDUs regarding potential SIF program participation prior to its opening independently predicted later attendance even when variables that were likely determinants of willingness were adjusted for. These data suggest that willingness measures are reasonably valid tools for planning the delivery of health services among IDU populations.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, Vancouver, Canada.
authors.forename: Kora
authors.initials: K
authors.lastname: DeBeck
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.forename: Calvin
authors.initials: C
authors.lastname: Lai
authors.forename: Jane
authors.initials: J
authors.lastname: Buxton
authors.forename: Julio
authors.initials: J
authors.lastname: Montaner
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
mesh_terms: D000328:Adult; D055030:Drug Users / Q000523:psychology*; D005260:Female; D006703:Ill-Housed Persons / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018671:Needle-Exchange Programs / Q000706:statistics & numerical data*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D015819:Substance Abuse, Intravenous / Q000523:psychology*