The projected costs and benefits of a supervised injection facility in Seattle, WA, USA.

Background: As one strategy to improve the health and survival of people who inject drugs, the King County Heroin & Opioid Addiction Task Force recommended the establishment of supervised injection facilities (SIF) where people can inject drugs in a safe and hygienic environment with clinical supervision. Analyses for other sites have found them to be cost-effective, but it is not clear whether these findings are transferable to other settings.

Methods: We utilized local estimates and other data sources deemed appropriate for our setting to implement a mathematical model that assesses the impact of a hypothetical SIF on overdose deaths, non-fatal overdose health service utilization, skin and soft tissue infections, bacterial infections, viral infections, and enrollment in medication assisted treatment (MAT). We estimated the costs and savings that would occur on an annual basis for a small-scale pilot site given current overdose rates, as well as three other scenarios of varying scale and underlying overdose rates.

Results: Assuming current overdose rates, a hypothetical Seattle SIF in a pilot phase is projected to annually reverse 167 overdoses and prevent 6 overdose deaths, 45 hospitalizations, 90 emergency department visits, and 92 emergency medical service deployments. Additionally, the site would facilitate the enrollment of 41 SIF clients in medication assisted treatment programs. These health benefits correspond to a monetary value of $5,156,019. The annual estimated cost of running the SIF is $1,222,332. The corresponding cost-benefit ratio suggests that the pilot SIF would generate $4.22 for every dollar spent on SIF operational costs. The pilot SIF is projected to save the healthcare system $534,453. If Seattle experienced elevated overdose rates and Seattle SIF program were scaled up, the health benefits and financial value would be considerably greater.

Conclusion: This analysis suggests that a SIF program in Seattle would save lives and result in considerable health benefits and cost savings.