Table 1 Summary of costing studies conducted on SIFs

The cost-effectiveness of Vancouver’s supervised injection facility (Bayoumi AM, Zaric GS). 2008[15]

Dynamic compartmental model; 10-year time horizon

▪ IDUs, non-users, persons with HIV and HCV, those with combinations of these states

▪ Over 10-year time horizon, the introduction of a SIF in Vancouver would prevent 1191 cases of HIV and 54 cases of HCV

▪ Sexual transmission, transmission through needle sharing

▪ Negative net cost of SIF

▪ Population, population shifts

▪ Vancouver SIF would save money and increase life expectancy

▪ Annual costs

A cost–benefit and cost-effectiveness analysis of Vancouver’s supervised injection facility (Andresen MA, Boyd NT). 2010[8]

Mathematical modelling

▪ Number of IDUs in population, number of sharing partners, participation rate at Insite

▪ Insite has a positive impact on the health outcomes of IDU population

▪ Number of needles used per client-year, number of needles in circulation, percentage of HIV infected needles, percentage of needles not cleaned

▪ Vancouver SIF prevents 35 new cases of HIV and almost 3 deaths annually.

▪ Number and rate of shared injections per year

▪ Provides societal benefit in excess of $6 million per year after programme costs are taken into account

▪ Probability of HIV infection from a single injection, cumulative probability of HIV infection, HIV prevalence rate

▪ Average benefit-cost ratio of 5.12:1

▪ Reduction of risk from participation

Is Vancouver Canada’s supervised injection facility cost-saving? (Pinkerton SD). 2010[16]

Mathematical modelling 1-year time frame

▪ IDUs living in Vancouver

▪ If Insite were closed, HIV infections among Vancouver IDU would increase from 179.3 (1.6% annual incidence) to 262.8 (2.3% incidence)

▪ Prevalence of HIV infection (%), annual incidence of HIV infection (%)

▪ This represents a difference of 83.5 infections per year

▪ Injections per IDU, per year, injections with borrowed syringes (%), supervised facility injections, per year

▪ These preventable infections would be associated with $17.6 million in life-time HIV-related medical costs

▪ Syringes distributed in Vancouver, per year, syringes distributed by Insite SEP, syringes distributed by

▪ The savings in cost exceeds Insite’s annual operating costs of approximately $3 million.

▪ non-Insite sources

▪ Most infections were prevented thanks to Insite’s syringe exchange program, which would prevent 80.7 infections

▪ Annual operating cost (Canadian $)

How many HIV infections are prevented by Vancouver Canada’s supervised injection facility? (Pinkerton SD). 2011[17]

Mathematical modelling

▪ Number of IDUs

▪ Vancouver SIF prevents approximately 5–6 infections per year, with a range of 4–8 prevented infections

▪ HIV prevalence, per injection transmission rate

▪ Insite SIF reduces HIV incidence among DTES IDU by 6-11%

▪ Incidence rate without Insite, incidence reduction

▪ Syringes contaminated with HIV, decontamination rate

▪ Borrows per IDU per year with Insite, reduction in number of borrows

▪ SIF injections per IDU per year

Potential role of safer injection facilities in reducing HIV and Hepatitis C infections and overdose mortality in the United States (Semaan S, Fleming P, Worrell C, Stolp H, Baack B, Miller M). 2011[28]

Six-factor Kass ethical framework for public health programs (goals, effectiveness, concerns, minimization of concerns, fair implementation, and balancing of benefits and concerns)

▪ Public health goals of SIFs and need for SIFs

▪ SIFs provide settings and public health interventions that support safer behaviors and aim to prevent and reduce HIV, HBV and HCV infections, infection disparities, overdose mortality, and injection-related bacterial infections

▪ Effectiveness of SIFs in achieving public health goals

▪ SIFs are cost-saving and cost-effective, prevent accidental needle-stick injuries in community members, and reduce public nuisance and litter

▪ Potential concerns

▪ SIFs provide unique and complimentary services to other public health interventions that promise to improve the health of PWIDs and the public order and safety of communities blighted by public injection

▪ Minimization of concerns and role of other programs

▪ SIFs provide sterile injection and drug preparation equipment at time of injection, a safe and medically attended environment, and on-site counseling or referrals to health and social services, including addiction treatment and housing

▪ Fair implementation of important ethical and contextual factors that influence the ethical deliberations and operational aspects of public health programs

The point of diminishing returns: an examination of expanding Vancouver’s Insite (Andresen MA, Jozaghi E). 2012[14]

Mathematical modelling (Jacobs et al. (1999) mathematical model)

▪ Expanding Insite’s hours of operation

▪ Insite operational for 18 hours predicts that 22 new cases of HIV are averted annually

▪ Increasing the number of SIFs

▪ Insite is cost-saving. The cost-benefit ratio is 3.09. The number of new HIV infections averted, and the associated cost-savings, are more than enough to cover Insite’s annual operating costs

▪ Proportion of IDUs HIV-negative

▪ Insite operational for 24 hours does not prevent any new HIV infections

▪ Number of needles in circulation

▪ Expansions of Insite only prevent 1 or 2 additional new cases of HIV infection

▪ Rate of needle-sharing

▪ Percentage of needles not cleaned

▪ Proportion of IDUs HIV-positive

▪ Probability of HIV infection from single injection

▪ Number of sharing partners

A cost-benefit/cost-effectiveness analysis of proposed supervised injection facilities in Montreal, Canada (Jozaghi E, Reid AA, Andresen MA). 2013[18]

Mathematical modelling using secondary data

▪ Proportion of IDUs HIV-negative, proportion of IDUs HIV-positive, proportion of IDUs HCV-negative, proportion of IDUs HCV-positive

▪ Increasing scope of SIFs through site expansion would result in 14–53 fewer HIV and 84–327 fewer HCV cases annually. The marginal range would result in 5–14 fewer HIV and 33–84 fewer HCV cases annually

▪ Number of needles in circulation, percentage of needles not cleaned, rate of needle sharing

▪ Establishing SIFs in Montreal will benefit the health care system and expanding SIFs would be a fiscally responsible course of action

▪ Probability of HIV infections from a single injection, probability of HCV infection from single injection

▪ With the HIV and HCV cases averted, SIFs in Montreal would be cost-saving

▪ Number of sharing partners