The Ontario Integrated Supervised Injection Services Cohort Study of People Who Inject Drugs in Toronto, Canada (OiSIS-Toronto): Cohort Profile.

The Ontario Integrated Supervised Injection Services cohort in Toronto, Canada (OiSIS-Toronto) is an open prospective cohort of people who inject drugs (PWID). OiSIS-Toronto was established to evaluate the impacts of supervised consumption services (SCS) integrated within three community health agencies on health status and service use. The cohort includes PWID who do and do not use SCS, recruited via self-referral, snowball sampling, and community/street outreach. From 5 November 2018 to 19 March 2020, we enrolled 701 eligible PWID aged 18+ who lived in Toronto. Participants complete interviewer-administered questionnaires at baseline and semi-annually thereafter and are asked to consent to linkages with provincial healthcare administrative databases (90.2% consented; of whom 82.4% were successfully linked) and SCS client databases. At baseline, 86.5% of participants (64.0% cisgender men, median ([IQR] age= 39 [33-49]) had used SCS in the previous 6 months, of whom most (69.7%) used SCS for <75% of their injections. A majority (56.8%) injected daily, and approximately half (48.0%) reported fentanyl as their most frequently injected drug. As of 23 April 2021, 291 (41.5%) participants had returned for follow-up. Administrative and self-report data are being used to (1) evaluate the impact of integrated SCS on healthcare use, uptake of community health agency services, and health outcomes; (2) identify barriers and facilitators to SCS use; and (3) identify potential enhancements to SCS delivery. Nested sub-studies include evaluation of "safer opioid supply" programs and impacts of COVID-19.