Patterns of injection drug use cessation during an expansion of syringe exchange services in a Canadian setting

Background: Needle and syringe programmes (NSPs) have been shown to reduce HIV risk among people who inject drugs (IDUs). However, concerns remain that NSPs delay injecting cessation.

Methods: Individuals reporting injection drug use in the past six months in the greater Vancouver area were enrolled in the Vancouver Injection Drug Users Study (VIDUS). Annual estimates of the proportion of IDU reporting injecting cessation were generated. Generalized estimating equation (GEE) analysis was used to assess factors associated with injecting cessation during a period of NSP expansion.

Results: Between May 1996 and December 2010, the number of NSP sites in Vancouver increased from 1 to 29 (P<0.001). The estimated proportion of participants (n=2710) reporting cessation increased from 2.4% (95% confidence interval [CI]: 0.0-7.0%) in 1996 to 47.9% (95% CI: 46.8-48.9%) in 2010 (P<0.001). In a multivariate GEE analysis, the authors observed an association between increasing calendar year and increased likelihood of injecting cessation (Adjusted Odds Ratio=1.17, 95% CI: 1.15, 1.19, P<0.001).

Conclusion: The proportion of IDU reporting injecting cessation increased during a period of NSP expansion, implying that increased NSP availability did not delay injection cessation. These results should help inform community decisions on whether to implement NSPs.