Changes in supervised consumption site use and emergency interventions in Montréal, Canada in the first twelve months of the COVID-19 pandemic: An interrupted time series study

BACKGROUND: The COVID-19 pandemic has impacted supervised consumption site (SCS) operations in Montréal, Canada, potentially including changes in SCS visits, on-site emergency interventions, injection of specific drugs, and distribution of harm reduction materials. METHOD: We used administrative data from all four Montréal SCS from 1 March 2018 - 28 February 2021 to conduct an interrupted time series study with 13 March 2020 as the intervention point. We employed segmented regression using generalised least squares fit by maximum likelihood. We analysed monthly SCS visits and materials distributed as counts, and emergency interventions and drugs injected as proportions of visits. RESULTS: SCS visits (level change = -1,286; 95% CI [-1,642, -931]) and the proportion of visits requiring emergency intervention (level = -0.27% [-0.47%, -0.06%]) decreased immediately in March 2020, followed by an increasing trend in emergency interventions (slope change = 0.12% [0.10%, 0.14%]) over the ensuing 12 months. Over the same period, the proportion of injections involving opioids increased (slope = 0.05% [0.03%, 0.07%]), driven by increasing pharmaceutical opioid and novel synthetic opioid injections. Novel synthetic opioids were the drugs most often injected prior to overdose. The proportion of injections involving unregulated amphetamines increased immediately (level = 7.83% [2.93%, 12.73%]), then decreased over the next 12 months (slope = -1.86% [-2.51%, -1.21%]). There was an immediate increase in needle/syringe distribution (level = 16,552.81 [2,373, 30,732]), followed by a decreasing trend (slope = -2,398 [-4,218, -578]). There were no changes in pre-existing increasing trends in naloxone or fentanyl test strip distribution. CONCLUSION: Reduced SCS use and increasing emergency interventions at SCS are cause for serious concern. Findings suggest increased availability of novel synthetic opioids in Montréal, heightening overdose risk.