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. Conclusion: 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.

• injection drug use
• supervised injection facilities
• validity of willingness measures

ACKNOWLEDGMENTS

We thank the study participants for their contribution to the research, as well as current and past researchers and staff. We would specifically thank Deborah Graham, Tricia Collingham, Carmen Rock, Peter Vann, Caitlin Johnston, Steve Kain, Danny Kain, and Calvin Lai for their research and administrative assistance. The study was supported by the US National Institutes of Health (R01DA011591 and R01DA021525) and the Canadian Institutes of Health Research (MOP–79297, RAA–79918). Thomas Kerr is supported by the Michael Smith Foundation for Health Research and the Canadian Institutes of Health Research. Kora DeBeck is supported by a Michael Smith Foundation for Health Research Senior Graduate Trainee Award and a Canadian Institutes of Health Research Doctoral Research Award. Julio Montaner has received an Avant-Garde Award (DP1DA026182) from the National Institute of Drug Abuse, US National Institutes of Health.

Declaration of Interest

Dr. Julio Montaner has received grants from, served as an ad hoc advisor to, or spoke at various events sponsored by Abbott, Argos Therapeutics, Bioject Inc., Boehringer Ingelheim, Bristol-Myers Squibb (BMS), Gilead Sciences, GlaxoSmithKline, Hoffmann-La Roche, Janssen-Ortho, Merck Frosst, Pfizer, Schering, Serono Inc., TheraTechnologies, Tibotec, and Trimeris. The authors declare no other competing interests.