The impact of the COVID-19 pandemic on people who use drugs in three Canadian cities: a cross-sectional analysis.

BACKGROUND: The COVID-19 pandemic had a disproportionate impact on the health and wellbeing of people who use drugs (PWUD) in Canada. However less is known about jurisdictional commonalities and differences in COVID-19 exposure and impacts of pandemic-related restrictions on competing health and social risks among PWUD living in large urban centres. METHODS: Between May 2020 and March 2021, leveraging infrastructure from ongoing cohorts of PWUD, we surveyed 1,025 participants from Vancouver (n = 640), Toronto (n = 158), and Montreal (n = 227), Canada to describe the impacts of pandemic-related restrictions on basic, health, and harm reduction needs. RESULTS: Among participants, awareness of COVID-19 protective measures was high; however, between 10 and 24% of participants in each city-specific sample reported being unable to self-isolate. Overall, 3-19% of participants reported experiencing homelessness after the onset of the pandemic, while 20-41% reported that they went hungry more often than usual. Furthermore, 8-33% of participants reported experiencing an overdose during the pandemic, though most indicated no change in overdose frequency compared the pre-pandemic period. Most participants receiving opioid agonist therapy in the past six months reported treatment continuity during the pandemic (87-93%), however, 32% and 22% of participants in Toronto and Montreal reported missing doses due to service disruptions. There were some reports of difficulty accessing supervised consumption sites in all three sites, and drug checking services in Vancouver. CONCLUSION: Findings suggest PWUD in Canada experienced difficulties meeting essential needs and accessing some harm reduction services during the COVID-19 pandemic. These findings can inform preparedness planning for future public health emergencies.

Overdose mortality incidence and supervised consumption services in Toronto, Canada: an ecological study and spatial analysis.

BACKGROUND: Supervised consumption services (SCS) prevent overdose deaths onsite; however, less is known about their effect on population-level overdose mortality. We aimed to characterise overdose mortality in Toronto, ON, Canada, and to establish the spatial association between SCS locations and overdose mortality events. METHODS: For this ecological study and spatial analysis, we compared crude overdose mortality rates before and after the implementation of nine SCS in Toronto in 2017. Data were obtained from the Office of the Chief Coroner of Ontario on cases of accidental death within the City of Toronto for which the cause of death involved the use of an opiate, synthetic or semi-synthetic opioid, or other psychoactive substance. We assessed overdose incident data for global spatial autocorrelation and local clustering, then used geographically weighted regression to model the association between SCS proximity and overdose mortality incidence in 2018 and 2019. FINDINGS: We included 787 overdose mortality events in Toronto between May 1, 2017, and Dec 31, 2019. The overdose mortality rate decreased significantly in neighbourhoods that implemented SCS (8·10 deaths per 100 000 people for May 1-July 31, 2017, vs 2·70 deaths per 100 000 people for May 1-July 31, 2019; p=0·037), but not in other neighbourhoods. In a geographically weighted regression analysis that adjusted for the availability of substance-use-related services and overdose-related sociodemographic factors by neighbourhood, the strongest local regression coefficients of the association between SCS and overdose mortality location ranged from -0·60 to -0·64 per mile in 2018 and from -1·68 to -1·96 per mile in 2019, suggesting an inverse association. INTERPRETATION: We found that the period during which SCS were implemented in Toronto was associated with a reduced overdose mortality in surrounding neighbourhoods. The magnitude of this inverse association increased from 2018 to 2019, equalling approximately two overdose fatalities per 100 000 people averted in the square mile surrounding SCS in 2019. Policy makers should consider implementing and sustaining SCS across neighbourhoods where overdose mortality is high. FUNDING: The Canadian Institutes of Health Research.

Latent polydrug use patterns and the provision of injection initiation assistance among people who inject drugs in three North American settings.

INTRODUCTION: We sought to identify latent profiles of polysubstance use patterns among people who inject drugs in three distinct North American settings, and then determine whether profile membership was associated with providing injection initiation assistance to injection-naïve persons. METHODS: Cross-sectional data from three linked cohorts in Vancouver, Canada; Tijuana, Mexico; and San Diego, USA were used to conduct separate latent profile analyses based on recent (i.e., past 6 months) injection and non-injection drug use frequency. We then assessed the association between polysubstance use patterns and recent injection initiation assistance provision using logistic regression analyses. RESULTS: A 6-class model for Vancouver participants, a 4-class model for Tijuana participants and a 4-class model for San Diego participants were selected based on statistical indices of fit and interpretability. In all settings, at least one profile included high-frequency polysubstance use of crystal methamphetamine and heroin. In Vancouver, several profiles were associated with a greater likelihood of providing recent injection initiation assistance compared to the referent profile (low-frequency use of all drugs) in unadjusted and adjusted analyses, however, the inclusion of latent profile membership in the multivariable model did not significantly improve model fit. DISCUSSION AND CONCLUSIONS: We identified commonalities and differences in polysubstance use patterns among people who inject drugs in three settings disproportionately impacted by injection drug use. Our results also suggest that other factors may be of greater priority when tailoring interventions to reduce the incidence of injection initiation. These findings can aid in efforts to identify and support specific higher-risk subpopulations of people who inject drugs.

Drug checking use and interest among people who inject drugs in Toronto, Canada.

BACKGROUND: Drug checking services (DCS) provide information on drug composition to inform consumption practices and monitor unregulated drug markets. We sought to identify correlates of recent informal DCS use (e.g., fentanyl test strips) and willingness to use a formal DCS (co-located within a supervised consumption site and employing laboratory-based analyses) in Toronto, Canada prior to its implementation. METHODS: We calculated outcome prevalence based on baseline questionnaire data from a cohort of people who inject drugs in downtown Toronto between November 2018-October 2019 and conducted multivariable Poisson regression analyses. Outcomes included recent (i.e., past six-month) informal DCS use and willingness to use a formal DCS, if implemented. We also conducted a sub-analysis assessing willingness to use a formal DCS following an unexpected drug reaction. RESULTS: Among 604 participants, 12% (n=74) reported recent informal DCS use, 73% (n=442) reported willingness to use a formal DCS, and 88% (n=530) reported willingness to use a formal DCS in response to an unexpected drug reaction. Based on 567 participants with complete data, we found that recent injection at a supervised consumption site or overdose prevention site were both associated with recent informal DCS use (respectively, adjusted prevalence ratio [aPR]=2.44, 95% confidence interval [CI]: 1.11-5.35; aPR=1.78, 95% CI: 1.00-3.15). Recent informal DCS use and recent overdose were both associated with willingness to use a formal DCS (respectively, aPR=1.15, 95% CI: 1.02-1.30; aPR=1.10, 95% CI: 1.00-1.22). CONCLUSION: Although recent informal DCS use was infrequently reported in our study, willingness to use a formal DCS was high. Our findings indicate a potential role for laboratory-based DCS in mitigating overdose risk among individuals accessing the unregulated drug supply. However, barriers that impede service access or reduce interest should be addressed to ensure equitable use among those at heightened risk of overdose.

The influence of poly-drug use patterns on the association between opioid agonist treatment engagement and injecting initiation assistance.

BACKGROUND: Evidence suggests people who inject drugs (PWID) prescribed opioid agonist treatment (OAT) are less likely to provide injection drug use (IDU) initiation assistance. We investigated the association between OAT engagement and providing IDU initiation assistance across poly-drug use practices in Vancouver, Canada. METHODS: Preventing Injecting by Modifying Existing Responses (PRIMER) is a prospective study seeking to identify structural interventions that reduce IDU initiation. We employed data from linked cohorts of PWID in Vancouver and extended the findings of a latent profile analysis (LPA). Multivariable logistic regression models were performed separately for the six poly-drug use LPA classes. The outcome was recently assisting others in IDU initiation; the independent variable was recent OAT engagement. RESULTS: Among participants (n = 1218), 85 (7.0%) reported recently providing injection initiation assistance. When adjusting for age and sex, OAT engagement among those who reported a combination of high-frequency heroin and methamphetamine IDU and low-to-moderate-frequency prescription opioid IDU and methamphetamine non-injection drug use (NIDU) was associated with lower odds of IDU initiation assistance provision (Adjusted Odds Ratio [AOR]: 0.18, 95% CI: 0.05-0.63, P = 0.008). Significant associations were not detected among other LPA classes. CONCLUSIONS: Our findings extend evidence suggesting that OAT may provide a population-level protective effect on the incidence of IDU initiation and suggest that this effect may be specific among PWID who engage in high-frequency methamphetamine and opioid use. Future research should seek to longitudinally investigate potential causal pathways explaining the association between OAT and initiation assistance provision among PWID to develop tailored intervention efforts.

Health harms of non-medical prescription opioid use: A systematic review.

ISSUES: Non-medical prescription opioid use (NMPOU) contributes substantially to the global burden of morbidity. However, no systematic assessment of the scientific literature on the associations between NMPOU and health outcomes has yet been undertaken. APPROACH: We undertook a systematic review evaluating health outcomes related to NMPOU based on ICD-10 clinical domains. We searched 13 electronic databases for original research articles until 1 July 2021. We employed an adaptation of the Oxford Centre for Evidence-Based Medicine 'Levels of Evidence' scale to assess study quality. KEY FINDINGS: Overall, 182 studies were included. The evidence base was largest on the association between NMPOU and mental and behavioural disorders; 71% (129) studies reported on these outcomes. Less evidence exists on the association of NMPOU with infectious disease outcomes (26; 14%), and on external causes of morbidity and mortality, with 13 (7%) studies assessing its association with intentional self-harm and 1 study assessing its association with assault (<1%). IMPLICATIONS: A large body of evidence has identified associations between NMPOU and opioid use disorder as well as on fatal and non-fatal overdose. We found equivocal evidence on the association between NMPOU and the acquisition of HIV, hepatitis C and other infectious diseases. We identified weak evidence regarding the potential association between NMPOU and intentional self-harm, suicidal ideation and assault. DISCUSSION AND CONCLUSIONS: Findings may inform the prevention of harms associated with NMPOU, although higher-quality research is needed to characterise the association between NMPOU and the full spectrum of physical and mental health disorders.

Drug checking services for people who use drugs: a systematic review.

BACKGROUND AND AIMS: Drug checking services provide people who use drugs with chemical analysis results of their drug samples while simultaneously monitoring the unregulated drug market. We sought to identify and synthesize literature on the following domains: (a) the influence of drug checking services on the behaviour of people who use drugs; (b) monitoring of drug markets by drug checking services; and (c) outcomes related to models of drug checking services. METHODS: Systematic review. A systematic literature search was conducted in MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, PsycINFO, Scopus, Web of Science and Dissertations and Theses Global. Eligible studies were peer-reviewed articles and conference abstracts or grey literature, published in any language since 1990 and including original data on the domains. We assessed risk of bias for quantitative peer-reviewed articles reporting on behaviour or models of drug checking services using National Institutes of Health tools. RESULTS: We screened 2463 titles and abstracts and 156 full texts, with 90 studies meeting inclusion criteria. Most (n = 65, 72.2%) were from Europe and used cross-sectional designs (n = 79, 87.7%). Monitoring of drug markets by drug checking services (n = 63, 70%) was the most reported domain, followed by the influence of drug checking services on behaviour (n = 31, 34.4%), including intent to use, actual use and disposal of the drug, and outcomes related to models of drug checking services (n = 17, 18.9%). The most common outcome measures were detection of unexpected substances (n = 50, 55.6%), expected substances (n = 44, 48.9%), new psychoactive substances (n = 40, 44.4%) and drugs of concern (n = 32, 36.5%) by drug checking services. CONCLUSIONS: Drug checking services appear to influence behavioural intentions and the behaviour of people who use drugs, particularly when results from drug checking services are unexpected or drugs of concern. Monitoring of drug markets by drug checking services is well established in Europe, and increasingly in North America. Concerns about drug contents and negative health consequences facilitate the use of drug checking services; lack of concern; trust in drug sellers; lack of accessibility of drug checking services; and legal and privacy concerns are barriers to use.