A cost-benefit and cost-effectiveness analysis of Vancouver's supervised injection facility.

BACKGROUND A supervised injection facility (SIF) has been established in North America: Insite, in Vancouver, British Columbia. The purpose of this paper is to conduct a cost-effectiveness and cost-benefit analysis of this SIF using secondary data gathered and analysed in 2008. In using these data we seek to determine whether the facility's prevention of infections and deaths among injecting drug users (IDUs) is of greater or lesser economic cost than the cost involved in providing this service - Insite - to this community. METHODS Mathematical modelling is used to estimate the number of new HIV infections and deaths prevented each year. We use the number of these new HIV infections and deaths prevented, in conjunction with estimated lifetime public health care costs of a new HIV infection, and the value of a life, in order to calculate an identifiable portion of the societal benefits of Insite. The annual costs of operating the SIF are used to measure the social costs of Insite. In using this information, we calculate cost-effectiveness and benefit-cost ratios for the SIF. RESULTS Through the use of conservative estimates, Vancouver's SIF, Insite, on average, prevents 35 new cases of HIV and almost 3 deaths each year. This provides a societal benefit in excess of $6 million per year after the programme costs are taken into account, translating into an average benefit-cost ratio of 5.12:1. CONCLUSION Vancouver's SIF appears to be an effective and efficient use of public health care resources, based on a modelling study of only two specific and measurable benefits-HIV infection and overdose death.