Search

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., (© 2023 The Authors. Drug and Alcohol Review published by John Wiley & Sons Australia, Ltd on behalf of Australasian Professional Society on Alcohol and other Drugs.)

Background: Accumulating evidence has indicated that cannabis substitution is often used as a harm reduction strategy among people who use unregulated opioids (PWUO) and people living with chronic pain. We sought to investigate the association between cannabis use to manage opioid cravings and self-reported changes in opioid use among structurally marginalized PWUO., Methods: The data were collected from a cross-sectional questionnaire administered to PWUO in Vancouver, Canada. Binary logistic regression was used to analyze the association between cannabis use to manage opioid cravings and self-reported changes in unregulated opioid use., Results: A total of 205 people who use cannabis and opioids were enrolled in the present study from December 2019 to November 2021. Cannabis use to manage opioid cravings was reported by 118 (57.6%) participants. In the multivariable analysis, cannabis use to manage opioid cravings (adjusted Odds Ratio [aOR] = 2.13, 95% confidence interval [CI]: 1.07, 4.27) was significantly associated with self-reported reductions in opioid use. In the sub-analyses of pain, cannabis use to manage opioid cravings was only associated with self-assessed reductions in opioid use among people living with moderate to severe pain (aOR = 4.44, 95% CI: 1.52, 12.97). In the sub-analyses of males and females, cannabis use to manage opioid cravings was only associated with self-assessed reductions in opioid use among females (aOR = 8.19, 95% CI: 1.20, 55.81)., Conclusions: These findings indicate that cannabis use to manage opioid cravings is a prevalent motivation for cannabis use among PWUO and is associated with self-assessed reductions in opioid use during periods of cannabis use. Increasing the accessibility of cannabis products for therapeutic use may be a useful supplementary strategy to mitigate exposure to unregulated opioids and associated harm during the ongoing drug toxicity crisis., Competing Interests: Declaration of Competing Interest Hudson Reddon: None to declare. Stephanie Lake: None to declare. Maria Eugenia Socias: None to declare. Kanna Hayashi: None to declare. Kora DeBeck: None to declare. Zach Walsh: None to declare. M-JM is the Canopy Growth professor of cannabis science at the University of British Columbia (UBC), a position created using unstructured arms’ length gifts to the university from Canopy Growth Corporation, a licensed producer of cannabis, and the Government of British Columbia's Ministry of Mental Health and Addictions. He has no financial relationships with the cannabis industry. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objective: To examine prevalence and factors associated with food insecurity among people who use drugs (PWUD) during the first year of the COVID-19 pandemic and the overdose crisis., Design: This cross-sectional study employs multivariable logistic regression to identify factors associated with self-reported food insecurity., Participants: PWUD who are part of three community-recruited cohorts., Setting: Interviews conducted in Vancouver, Canada, via phone between July and November 2020 in adherence to COVID-19 safety procedures., Results: Among 765 participants, including 433 (56·6 %) men, eligible for this study, 146 (19·1 %; 95 % CI: 16·3 %, 21·9 %) reported food insecurity in the past month. Of the participants reporting food insecurity, 114 (78·1 %) reported that their hunger levels had increased since the beginning of the pandemic. In multivariable analyses, factors independently and positively associated with food insecurity included: difficulty accessing health or social services (adjusted OR (AOR) = 2·59; 95 % CI: 1·60, 4·17); having mobility difficulties (AOR = 1·59; 95 % CI: 1·02, 2·45) and engaging in street-based income generation (e.g. panhandling and informal recycling) (AOR = 2·31; 95 % CI: 1·45, 3·65)., Conclusion: Approximately one in five PWUD reported food insecurity during this time. PWUD with mobility issues, who experienced difficulty accessing services and/or those engaged in precarious street-based income generation were more likely to report food insecurity. Food security is paramount to the success of interventions to prevent COVID-19 and drug toxicity deaths. These findings suggest a need for a more unified state response to food insecurity that prioritises and incorporates accessibility and autonomy of the communities they serve.

Background: Several jurisdictions in Canada have recently considered decriminalizing possession of illicit drugs for personal use (henceforth, simple possession) as part of their responses to the ongoing drug toxicity/overdose crisis. In this context, we sought to examine an early implementation case of a de facto depenalization policy of simple possession offences in Vancouver, Canada, that was enacted in 2006. Specifically, we characterized experiences of people who use drugs (PWUD) whose drugs were discretionally seized by police without arrest., Methods: Data were derived from three prospective cohorts of community-recruited PWUD in Vancouver over 16 months in 2019-2021. We conducted multivariable generalized estimating equations analyses to determine the prevalence of and factors associated with drug seizure. Sub-analyses used data collected in 2009-2012 and examined the trends over time., Results: Among 995 participants who were interviewed in 2019-2021, 63 (6.3%) had their drugs seized by police at least once in the past 6 months. In multivariable analyses, factors significantly associated with drug seizure included: homelessness (adjusted odds ratio [AOR]: 1.98; 95% confidence interval [CI] 1.09-3.61), working in the unregulated drug market (AOR: 4.93; 95% CI 2.87-8.49), and naloxone administration (AOR: 2.15; 95% CI 1.23-3.76). In 2009-2012, 67.8% reported having obtained new drugs immediately after having their drugs seized by police. Odds of drug seizure were not significantly different between the two time periods (2019-2021 vs. 2009-2012) (AOR: 0.93; 95% CI: 0.64-1.35)., Conclusions: Despite the depenalization policy, the Vancouver Police Department has continued to seize illicit drugs from PWUD, even in cases where no arrest occurred. This policing practice may create health and safety risks for PWUD as it forces PWUD to increase the engagement with the unregulated illicit drug market. Our findings support calls for abolishing this often-undocumented discretionary policing practice that may exacerbate ongoing health inequities and interfere with peer-based overdose prevention efforts., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: Patient satisfaction is key to the success of methadone maintenance treatment (MMT), and yet how MMT satisfaction is affected by the increasingly common use of crystal methamphetamine among people receiving opioid treatment remains poorly understood. We aimed to assess the association between crystal methamphetamine use and MMT dissatisfaction., Methods: We employed generalized estimating equations to examine the relationship between crystal methamphetamine use and MMT dissatisfaction among patients receiving MMT within two prospective cohorts in Vancouver, Canada, between December 2016 and March 2020., Results: Of the 836 participants receiving MMT, the median age was 47 years, and 55.3 % self-identified as male at baseline. In a multivariable model, those reporting more than weekly crystal methamphetamine use were more likely to report MMT dissatisfaction (Odds ratio: 1.40, 95 % confidence interval: 1.05-1.86) compared to those reporting less than monthly crystal methamphetamine use., Conclusions: Among our sample of people receiving MMT, we noted a positive association of frequent crystal methamphetamine use with MMT dissatisfaction. Our study suggests a need for novel strategies to better understand and address frequent methamphetamine use among those receiving MMT, particularly given recent shifts in substance use patterns involving the rising co-use of methamphetamines and opioids., Competing Interests: Declaration of competing interest MJM's institution has received an unstructured gift from NG Biomed, Ltd., to support his research. MJM is the Canopy Growth professor of cannabis science at the University of British Columbia, a position created by unstructured gifts to the university from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia's Ministry of Mental Health and Addictions. Funding sources had no role in study design; collection, analysis, and interpretation of data; writing the report; and the decision to submit the report for publication. All authors declare no conflict of interest., (Copyright © 2023. Published by Elsevier Inc.)

Objective: The drug poisoning crisis throughout North America necessitates novel harm reduction approaches. Emerging evidence suggests that cannabidiol (CBD) may have some utility as a harm reduction modality for those with problematic substance use. This rapid review aimed to synthesize available evidence on CBD as a potential harm reduction tool for people who use drugs while providing clinical and research insights., Method: A systematic search in EMBASE, MEDLINE, CENTRAL, and CINAHL was completed in July 2022. For inclusion, studies had to meet the following criteria: (1) drawn from an adult population of people who use drugs; (2) investigates CBD as an intervention for problematic substance use or harm reduction-related outcomes; (3) be published after the year 2000 and in English; and (4) be primary research or a review article. A narrative synthesis was used to group outcomes relevant to harm reduction and provide clinical and research insights., Results: We screened 3,134 records, of which 27 studies (5 randomized trials) were included. The evidence remains limited, but available studies support the potential utility of CBD to reduce drug-induced craving and anxiety in opioid use disorder. There were low-quality studies suggesting that CBD may improve mood and general well-being of people who use drugs. Evidence suggests that CBD monotherapy may not be an adequate harm reduction strategy for problematic substance use but rather an adjunct to the standard of care., Conclusion: Low-quality evidence suggests that CBD may reduce drug cravings and other addiction-related symptoms and that CBD may have utility as an adjunct harm reduction strategy for people who use drugs. However, there is a significant need for more research that accurately reflects CBD dosing and administration regimens used in a real-world context.

Introduction: While substance use contributes to a substantial burden of disease, access to evidence-based harm reduction interventions remains limited or inaccessible. Preliminary research suggests that some individuals use cannabis to reduce the harms associated with their use of other substances, including opioids and stimulants. This study examines factors associated with the self-reported use of cannabis for harm reduction among people who use drugs (PWUD). Methods: We drew data from three prospective, community-recruited cohorts of PWUD in Vancouver, Canada, between June 2016 and May 2018. Multivariable generalized linear mixed-effects modeling was used to examine factors associated with the primary outcome of "use of cannabis for harm reduction," defined as self-reported use of cannabis to substitute for other substances, treat withdrawal, or come down off other drugs. Results: One thousand nine hundred thirty-six participants contributed 5706 observations. In adjusted analyses, daily methamphetamine use (adjusted odds ratio [AOR]=1.43, 95% confidence interval [CI]: 1.09-1.89), experiencing barriers to accessing addiction treatment (AOR=1.92, 95% CI: 1.21-3.03), and enrollment in addiction treatment modalities other than opioid agonist therapy (AOR=1.64, 95% CI: 1.17-2.29) were positively associated with using cannabis for harm reduction. Older age was negatively associated (AOR=0.97, 95% CI: 0.95-0.98). Among 1281 (66.2%) participants who use cannabis, daily cannabis use and obtaining cannabis from unregulated dispensaries were also independent correlates of using cannabis for harm reduction. Discussion and Conclusions: Individuals who were more likely to use cannabis for harm reduction reported difficulty accessing addiction treatment or used substances, such as methamphetamines, where effective treatments are limited. These findings highlight the need to better understand the potential harm-reducing impacts of cannabis among PWUD in these scenarios.

Objective: Unregulated stimulant use is rising globally, though trends in use of cocaine and crystal methamphetamine (CM), the two most commonly used unregulated stimulants in North America, are poorly characterized in many settings. In this study we examined patterns and associations between the injection of cocaine and CM over time in an urban Canadian setting., Methods: The study collected data from two prospective cohorts of people who inject drugs in Vancouver, Canada, between 2008 and 2018. We applied a time series analysis, using multivariable linear regression to detect relationships between reported CM and cocaine injection and year, controlling for covariates. The study used cross-correlation to evaluate the relative trajectories of each substance over time., Results: Among 2056 participants, per annum rates of reported injection cocaine use declined significantly over the duration of this study from 45 % to 18 % (p < 0.001), while rates of CM injection increased from 17 % to 32 % (p < 0.001). Multivariable linear regression showed that recent CM injection was negatively associated with recent cocaine injection (β = -0.609, 95 % CI = -0.750, -0.467). Cross-correlation demonstrated that injection CM use was associated with a decrease in the likelihood of cocaine injection 12 months later (p = 0.002)., Conclusions: These findings demonstrate an epidemiological shift in patterns of injection stimulant use, with rising CM injection associated with a corresponding decrease in cocaine injection over time. Strategies are urgently needed that help to treat and reduce harm among the growing population of people who inject CM., Competing Interests: Declaration of competing interest The authors have no competing interests to declare. MJM declares no personal financial relationship with the cannabis industry., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: To investigate the longitudinal association between periods of homelessness and progression through the HIV cascade of care among people who use drugs (PWUD) with universal access to no-cost HIV treatment and care., Design: Prospective cohort study., Methods: Data were analysed from the ACCESS study, including systematic HIV clinical monitoring and a confidential linkage to comprehensive antiretroviral therapy (ART) dispensation records. We used cumulative link mixed-effects models to estimate the longitudinal relationship between periods of homelessness and progression though the HIV cascade of care., Results: Between 2005 and 2019, 947 people living with HIV were enrolled in the ACCESS study and 304 (32.1%) reported being homeless at baseline. Homelessness was negatively associated with overall progression through the HIV cascade of care [adjusted partial proportional odds ratio (APPO) = 0.56, 95% confidence interval (CI): 0.49-0.63]. Homelessness was significantly associated with lower odds of progressing to each subsequent stage of the HIV care cascade, with the exception of initial linkage to care., Conclusions: Homelessness was associated with a 44% decrease in the odds of overall progression through the HIV cascade of care, and a 41-54% decrease in the odds of receiving ART, being adherent to ART and achieving viral load suppression. These findings support calls for the integration of services to address intersecting challenges of HIV, substance use and homelessness among marginalized populations such as PWUD., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: We describe the prevalence of COVID-19 vaccine uptake, substance use, and other factors associated with vaccine hesitancy among participants from nine North American cohort studies following a diverse group of individuals at risk for or living with HIV., Methods: Between May 2021 and January 2022, participants completed a survey related to COVID-19 vaccination. Participants included those with and without substance use. Those responding as 'no' or 'undecided' to the question "Do you plan on getting the COVID-19 vaccine?" were categorized as vaccine hesitant. Differences between groups were evaluated using chi-square methods and multivariable log-binomial models were used to calculate prevalence ratios (PR) of COVID-19 vaccine hesitancy with separate models for each substance., Results: Among 1,696 participants, COVID-19 vaccination was deferred or declined by 16%. Vaccine hesitant participants were younger, with a greater proportion unstably housed (14.8% vs. 10.0%; p = 0.02), and not living with HIV (48.% vs. 36.6%; p <.01). Vaccine hesitant participants were also more likely to report cannabis (50.0% vs. 42.4%; p = 0.03), methamphetamine (14.0% vs. 8.2%; p <.01), or fentanyl use (5.5% vs. 2.8%; p = 0.03). Based on multivariable analyses methamphetamine or fentanyl use remained associated with COVID-19 vaccine hesitancy (Adjusted PR = 1.4; 95% CI 1.1-1.9 and Adjusted PR = 1.6; 95% CI 1.0-2.6, respectively)., Conclusion: As new COVID-19 vaccines and booster schedules become necessary, people who use drugs (PWUD) may remain vaccine hesitant. Strategies to engage hesitant populations such as PWUD will need to be tailored to include special types of outreach such as integration with substance use programs such as safe injection sites or recovery programs., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Objectives: People who use drugs (PWUD) experience disproportionately high rates of violent victimization. Emerging research has demonstrated that the COVID-19 pandemic has exacerbated violence against some priority populations (e.g., women), however there is limited research examining the impact of the pandemic on the experiences of violence of PWUD., Methods: Using data collected between July and November 2020 from three prospective cohort studies of PWUD in Vancouver, Canada, we employed multivariable logistic regression stratified by gender to identify factors associated with recent experiences of violence, including the receipt of COVID-19 emergency income support., Results: In total, 77 (17.3%) of 446 men, and 54 (18.8%) of 288 women experienced violence in the previous six months. Further, 33% of men and 48% of women who experienced violence reported that their experience of violence was intensified since the COVID-19 pandemic began. In the multivariable analyses, sex work (Adjusted Odds Ratio [AOR] = 2.15, 95% confidence interval [CI]: 1.06-4.35) and moderate to severe anxiety or depression (AOR = 3.00, 95% CI: 1.37-6.57) were associated with experiencing violence among women. Among men, drug dealing (AOR = 1.93, 95%CI: 1.10-3.38), street-based income sources (AOR = 1.93, 95%CI: 1.10-3.38), homelessness (AOR = 2.54, 95%CI: 1.40-4.62), and regular employment (AOR = 2.97, 95% CI: 1.75-5.04) were associated with experiencing violence., Conclusion: Our study results suggest economic conditions and gender were major factors associated with experiencing violence among our sample of PWUD during COVID-19. These findings highlight criminalization of drug use and widespread socioeconomic challenges as barriers to addressing violence among PWUD during periods of crisis., (© 2023. The Author(s).)

Background: Among people who inject drugs, frequent injecting and experiencing withdrawal are associated with facilitating others' first injections. As these factors may reflect an underlying substance use disorder, we investigated whether first-line oral opioid agonist treatment (OAT; methadone or buprenorphine/naloxone) reduces the likelihood that people who inject drugs help others initiate injecting., Methods: We used questionnaire data from semi-annual visits between December 2014-May 2018 on 334 people who inject drugs with frequent non-medical opioid use in Vancouver, Canada. We estimated the effect of current first-line OAT on subsequent injection initiation assistance provision (i.e., helped someone initiate injecting in the following six months) using inverse-probability-weighted estimation of repeated measures marginal structural models to reduce confounding and informative censoring by time-fixed and time-varying covariates., Results: By follow-up visit, 54-64% of participants reported current first-line OAT whereas 3.4-6.9% provided subsequent injection initiation assistance. Per the primary weighted estimate (n = 1114 person-visits), participants currently on first-line OAT (versus no OAT) were 50% less likely, on average, to subsequently help someone initiate injecting (relative risk [RR]=0.50, 95% CI=0.23-1.11). First-line OAT was associated with reduced risk of subsequent injection initiation assistance provision in participants who, at baseline, injected opioids less than daily (RR=0.15, 95% CI=0.05-0.44) but not in those who injected opioids daily (RR=0.86, 95% CI=0.35-2.11)., Conclusions: First-line OAT seemingly reduces the short-term likelihood that people who inject drugs facilitate first injections. However, the extent of this potential effect remains uncertain due to imprecise estimation and observed heterogeneity by baseline opioid injecting frequency., Competing Interests: The authors declare that they have no conflicts of interest., (© 2023 The Author(s).)

People living with HIV (PLWH) often experience stigma and discrimination by health care professionals. We investigated the prevalence of perceived mistreatment in health care settings and its associations with HIV clinical outcomes and health care-seeking behaviour using data from a long-running prospective cohort of PLWH who use drugs. Of the 857 participants included, 19% reported at least one instance of perceived mistreatment during the study period. In adjusted longitudinal analyses, perceived mistreatment was positively associated with not being on ART in the same follow-up period, and participants who reported perceived mistreatment were less likely to report seeing a physician in the subsequent follow-up period. Daily use of injection drugs was positively associated with reporting perceived mistreatment. These findings demonstrate the implications of negative health care interactions in a population that must consistently engage with the health care system, and the need for stigma-reducing educational interventions for health care professionals., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: People who use drugs (PWUD) are disproportionately incarcerated, however little is known about specific substance use, social and structural factors associated with re-incarceration among PWUD. We aimed to identify the socio-structural and substance use factors associated with re-incarceration among structurally-marginalized PWUD., Methods: We used longitudinal data from two prospective cohorts of PWUD in Vancouver, Canada. We included adults reporting at least one incarceration event in the last six months and who completed at least one additional follow-up study visit. We performed multivariable extended Cox regression to explore factors associated with re-incarceration., Results: Among 468 eligible participants, the median age was 40 years (Q1-Q3 = 34-46 years), 346 (73.9%) were men, 177 (37.8%) identified as Indigenous, and 227 (48.5%) experienced at least one re-incarceration event. Incidence rate of re-incarceration was 157 incarceration events per 1000 person years. In multivariable analyses, homelessness (adjusted hazard ratio [AHR] = 2.17; 95% confidence interval [95% CI]: 1.79-2.61), community judicial supervision (AHR = 3.89; 95% CI: 3.21-4.71) and re-incarceration during the study period (once: AHR = 1.95, 95% CI: 1.55-2.44; two or more events: AHR = 1.53, 95% CI: 1.23-1.90) were positively associated with re-incarceration. Among substance use variables that included illicit drugs, only heavy alcohol use remained significantly associated with re-incarceration across analyses after adjustment (AHR = 1.32; 95% CI: 1.06-1.65). Engagement in addiction treatment (AHR = 0.63; 95% CI: 0.53-0.75), mental illness (AHR = 0.70; 95% CI: 0.59-0.84) and age (AHR = 0.96; 95% CI: 0.95-0.97) were negatively associated with re-incarceration., Conclusion: Access to housing and substance use services, including treatment for alcohol use disorder, following incarceration may reduce re-incarceration among PWUD. The high rates of re-incarceration of PWUD in our sample underscores how structural factors-such as homelessness and criminalization of substance use-drive re-incarceration among PWUD., Competing Interests: Declarations of Interest M.J.M. is the Canopy Growth professor of cannabis science at the University of British Columbia, a position created by unstructured gifts to the university from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia's Ministry of Mental Health and Addictions. The funder that supports MJM had no role in study design; collection, analysis, and interpretation of data; writing the report; and the decision to submit the report for publication. All authors declare no conflict of interest., (Copyright © 2023. Published by Elsevier B.V.)

Although prevalent among people living with human immunodeficiency virus (HIV) (PLWH) and people who use unregulated drugs (PWUD), pain and its possible links to substance use patterns and engagement in HIV treatment remains poorly characterized. We sought to evaluate the prevalence and correlates of pain among a cohort of PLWH who use un-regulated drugs. Between December 2011 and November 2018, 709 participants were recruited, and data were analyzed using generalized linear mixed-effects (GLMM). At baseline, 374 (53 percent) individuals reported moderate-to-extreme pain in the previous 6 months. In a multivariable model, pain was significantly associated with nonmedical prescrip-tion-opioid use (adjusted odds ratio (AOR) = 1.63, 95 percent confidence interval (CI): 1.30-2.05), nonfatal overdose (AOR = 1.46, 95 percent CI: 1.11-1.93), self-managing pain (AOR = 2.25, 95 percent CI: 1.94-2.61), requesting pain medication in the previous 6 months (AOR = 2.01, 95 percent CI: 1.69-2.38), and ever being diagnosed with a mental illness (AOR = 1.47, 95 percent CI: 1.11-1.94). Establishing accessible pain management interventions that address the complex intersection of pain, drug use, and HIV-infection has potential to improve quality of life outcomes among this population.

Background: Supervised consumption sites (SCS) and overdose prevention sites (OPS) have been increasingly implemented in response to the ongoing overdose epidemic in Canada. Although there has been a dramatic increase in overdose deaths since the start of the SARS-CoV 2 (COVID-19) pandemic, little is known about how SCS access may have been affected by this pandemic. Therefore, we sought to characterize potential changes in access to SCS during the COVID-19 pandemic among people who use drugs (PWUD) in Vancouver, Canada., Methods: Between June and December 2020, data were collected through the Vancouver Injection Drug Users Study (VIDUS) and the AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS), two cohort studies involving people who use drugs. Multivariable logistic regression was used to examine individual, social and structural factors associated with self-reported reduced frequency of SCS/OPS use since COVID-19., Results: Among 428 participants, 223 (54.7%) self-identified as male. Among all individuals surveyed, 63 (14.8%) reported a decreased frequency of use of SCS/OPS since COVID-19. However, 281 (66%) reported that they "did not want to" access SCS in the last 6 months. In multivariable analyses, younger age, self-reported fentanyl contamination of drugs used and reduced ease of access to SCS/OPS since COVID-19 were positively associated with a decreased frequency of use of SCS/OPS since COVID-19 (all p < 0.05)., Conclusions: Approximately 15% of PWUD who accessed SCS/OPS reported reduced use of these programs during the COVID-19 pandemic, including those at heightened risk of overdose due to fentanyl exposure. Given the ongoing overdose epidemic, efforts must be made to remove barriers to SCS access throughout public health crises., (© 2023. The Author(s).)

Background: Methadone maintenance treatment (MMT) is an effective treatment for opioid use disorder. However, subtherapeutic dosing may lead to continued opioid use by failing to suppress opioid withdrawal and craving. Preclinical and pilot experimental research suggests that cannabinoids may reduce opioid withdrawal and craving. We sought to test whether the association between low methadone dose and illicit opioid use differs according to concurrent cannabis use patterns. Methods: Data for this study were derived from two community-recruited cohorts of people (≥18 years old) who use illicit drugs in Vancouver, Canada. We used generalized estimating equations to estimate the adjusted association between lower daily MMT dose (<90 mg/day) and daily illicit opioid use, testing for interaction between dose and daily cannabis use. Results: Between December 2005 and December 2018, 1389 participants reported MMT enrolment and were included in the study. We observed a significant interaction ( p <0.01) between daily cannabis and lower MMT dose on concurrent daily illicit opioid use: lower MMT doses increased the odds of daily illicit opioid use by 86% (adjusted odds ratio [AOR]=1.86, 95% confidence interval [CI]=1.61-2.16) during periods of no or low-frequency cannabis use and by 30% during periods of daily cannabis use (AOR=1.30, 95% CI=1.01-1.67). Discussion: This study provides preliminary observational evidence that cannabis may mitigate some of the negative effects of subtherapeutic MMT dosing, guiding future clinical investigations into the safety and efficacy of cannabis and cannabinoids as adjunct treatment for MMT.

Objectives: Lower daily methadone dose is negatively associated with retention in methadone maintenance treatment (MMT). Cannabis use during MMT is common, with many patients reporting its use for opioid withdrawal mitigation. We sought to test whether the association between lower MMT dose and treatment retention differs by concurrent high-frequency cannabis use in a community sample of people on MMT., Methods: We obtained data from participants initiating MMT in 2 community-recruited prospective cohorts of people who use drugs in Vancouver, Canada. We built multivariable Cox frailty models to estimate the relationships between MMT dose (<90 mg/d vs ≥90 mg/d) and time to treatment discontinuation. We included an interaction term to test whether high-frequency (≥daily) cannabis use modified the measured effect of lower treatment dose on treatment retention., Results: Between December 2005 and December 2018, 829 participants (54.1%) initiated at least 1 MMT episode and were included in the analysis. Lower MMT dose was strongly positively associated with treatment discontinuation regardless of concurrent high-frequency cannabis use (interaction P > 0.05). Structural factors including homelessness and incarceration were significantly and positively associated with treatment discontinuation., Conclusions: Although we previously found the magnitude and strength of the relationship between lower MMT dose and high-frequency unregulated opioid use to be tempered during high-frequency cannabis use periods, this effect measure modification does not appear to translate to time retained in treatment. Cannabis-based interventions to promote retention in MMT are unlikely to produce long-term benefit without addressing external factors that place MMT patients at increased risk of treatment discontinuation., Competing Interests: M-JM is the Canopy Growth professor of cannabis science at the University of British Columbia, a position created from unstructured arms' length gifts to the university from Canopy Growth Corporation, a licensed producer of cannabis, and the Government of British Columbia's Ministry of Mental Health and Addictions. University of British Columbia has also received unstructured funding from NG Biomed, Ltd., an applicant to the Canadian federal government for a license to produce cannabis, to support his research. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results. M-JM and MES were awarded funds by the Canadian Institutes of Health Research to study the safety and feasibility of codispensing tetrahydrocannabinol with methadone. Over the past 12 months, ZDC reports receiving honoraria from Canopy Growth Corporation. All other authors declare no conflicts of interest., (Copyright © 2022 American Society of Addiction Medicine.)

Background: The COVID-19 pandemic and consequent public health response may have undermined key responses to the protracted drug poisoning crisis, including reduced access to opioid agonist therapy (OAT) among people with opioid use disorder. Our study objectives were to estimate the prevalence of and identify factors associated with inability to contact OAT prescribers when in need among people on OAT in a Canadian setting during the dual public health crises., Methods: Survey data were collected from three prospective cohort studies of community-recruited people who use drugs between July and November 2020, in Vancouver, Canada. A multivariable logistic regression analysis was used to identify potential factors associated with inability to contact OAT prescribers among patients who accessed OAT in the past 6 months., Results: Among 448 respondents who reported accessing OAT in the past 6 months, including 231 (54.9%) men, 85 (19.0%) reported having been unable to contact OAT prescribers when needed, whereas 268 (59.8%) reported being able to talk to their prescriber when needed, and 95 (21.2%) reported that they did not want to talk to their medication prescriber in the previous 6 months. Among those who reported inability to contact prescribers, 45 (53.6%) reported that their overall ability to contact prescribers decreased since the start of the pandemic. In multivariable analyses, factors independently associated with inability to talk to OAT prescribers included: chronic pain (Adjusted Odds Ratio [AOR] = 1.82; 95% Confidence Interval [CI] 1.02, 3.27), moderate to severe symptoms of depression or anxiety (AOR = 4.74; 95% CI 2.30, 9.76), inability to access health/social services (AOR = 2.66; 95% CI 1.41, 5.02), and inability to self-isolate or socially distance most or all of the time (AOR = 2.13; 95% CI 1.10, 4.14)., Conclusions: Overall, approximately one fifth of the sample reported inability to contact their OAT prescribers when needed, and those people were more likely to have co-occurring vulnerabilities (i.e., co-morbidities, inability to access health/social services) and higher vulnerability to COVID-19. Interventions are needed to ensure optimal access to OAT and mitigate the deepening health inequities resulting from the COVID-19 pandemic and the escalating drug poisoning crisis., (© 2022. The Author(s).)

Background: Crystal methamphetamine use has substantially increased among people who use opioids in recent years, yet the impact of opioid agonist therapy (OAT) on crystal methamphetamine use remains poorly characterized. Therefore, we sought to examine the relationship between OAT engagement and crystal methamphetamine use and to assess if this relationship differs according to the ongoing use of unregulated opioids., Methods: Data was collected from two harmonized ongoing prospective cohorts of people who use drugs in Vancouver, Canada, between December 2005 and March 2020. We employed multivariable generalized estimating equations to study the relationship between OAT engagement and crystal meth use stratified by ongoing unregulated opioid use., Results: Of 1742 participants who reported frequent opioid use at baseline, the median age was 42 years, and 61.3% were male. Multivariable analyses showed that compared to those who had not received OAT for at least one year: in the absence of ongoing unregulated opioid use, individuals who recently discontinued (adjusted Odds Ratio [aOR] = 0.47, 95% CI = 0.27-0.79), newly initiated (aOR = 0.52, 95% CI = 0.31-0.89), or were retained on OAT (aOR = 0.48, 95% CI = 0.31-0.72) reported a lower frequency of crystal methamphetamine use; in the presence of ongoing unregulated opioid use, individuals who newly initiated OAT reported a greater crystal methamphetamine use frequency (aOR = 1.24, 95% CI = 1.02-1.51)., Conclusions: We demonstrated a differential relationship between OAT engagement and crystal methamphetamine use that was conditional on the ongoing use of unregulated opioids. Our findings highlight the complexity of OAT implementation and suggest that polysubstance use patterns should be an important consideration for care providers when devising comprehensive treatment strategies and prognosticating treatment effects., Competing Interests: Declarations of Interest MJM's institution has received an unstructured gift from NG Biomed, Ltd., to support his research. MJM is the Canopy Growth professor of cannabis science at the University of British Columbia, a position created by unstructured gifts to the university from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia's Ministry of Mental Health and Addictions. Funding sources had no role in study design; collection, analysis, and interpretation of data; writing the report; and the decision to submit the report for publication. All authors declare no conflict of interest., (Copyright © 2022. Published by Elsevier B.V.)

People living with (PLWH) and at risk for HIV and people who use drugs (PWUD) are at heightened risk for health consequences of COVID-19 because of compromised immunity and high comorbidities. We studied their use of COVID-19 testing during the first year of the COVID-19 pandemic. Eight NIDA funded cohorts across North America in the Collaborating Consortium of Cohorts Producing NIDA Opportunities (C3PNO) administered multiple waves of a COVID-19 survey. Respondents were at least 18 years of age, half PLWH, and many active substance users. Wave one of the COVID-19 survey was May-November, 2020 and wave two October 2020-April 2021. Associations of COVID-19 testing with demographics, socio-demographics, substance use, and HIV-status were assessed. Of the 3762 responses from 2331 individuals, half reported ever COVID-19 testing (49.1 %), with 4.3 % reporting a positive test (163/3762 surveys=4.3 %) and 41.5 % of people reporting current symptoms reported having been tested. In multivariable analysis adjusting for age, sex, and cohort type associations with COVID-19 testing included African American/Black identification compared to Caucasian/white (adjusted odds ratio (AOR)= 0.68; 95 % confidence interval (CI) 0.53, 0.88); being unemployed (AOR=0.61; 95 % CI 0.51, 0.73), and living with HIV (AOR=0.76; 95 % CI0.65, 0.90). Findings from these C3PNO COVID-19 modules suggests that in the first year of the pandemic COVID-19 testing was not broadly accessed by these marginalized populations including PLWH and those unemployed. Factors associated with not testing may also parallel those for vaccination and identify populations needing better access to COVID-19 prevention., Competing Interests: Conflict of Interest No conflict declared., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: The COVID-19 pandemic has compounded the longstanding drug poisoning crisis in Canada and the United States (US). Research is needed to understand the contributions of COVID-19 and subsequent infection control measures. We sought to estimate the prevalence of and factors associated with nonfatal overdose among participants in nine prospective cohorts of people who use unregulated drugs (PWUD) in Canada and the US., Methods: Data were derived from nine cohorts of PWUD in urban centres in Canada (Vancouver, BC) and the US (Baltimore, MD; Miami, FL; Chicago, IL; Los Angeles, CA) between May, 2020 and April, 2021. Multivariable logistic regression was used to identify factors associated with nonfatal overdose among participants who used unregulated drugs in the past month., Results: Among 885 participants (including 253 females), 41 (4.6 %) experienced a non-fatal overdose in the past month, and 453 (51.2 %) reported being highly impacted day-to-day by the pandemic. In multivariable analyses, people who experienced a non-fatal overdose were more likely to be female (Adjusted Odds Ratio [AOR]=2.18;95 % Confidence Interval [CI]=1.10-4.30); unstably housed/homeless (AOR=2.16;95 % CI=1.11-4.26); engaged in medications for opioid use disorder (AOR=2.45;95 % CI=1.19-4.97); and highly impacted day-to-day (AOR=2.42;95 % CI=1.22-5.10)., Conclusion: Our findings may reflect characteristics of participants who experienced a compounding of vulnerabilities during the pandemic and thus are vulnerable to overdose, including women, those unstably housed/homeless, and those who perceived their daily lives were highly impacted by the pandemic. Multi-level interventions are needed to remediate the vulnerabilities and address the main driver of poisoning crisis., Competing Interests: Conflict of interest M-JM holds the Canopy Growth professorship in cannabis science at the University of British Columbia, a position established through arm’s length gifts to the university from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia’s Ministry of Mental Health and Addictions. He has no financial relationships with the cannabis industry. All authors declare no conflict of interest., (Copyright © 2022. Published by Elsevier B.V.)

Background: This study examines individual-level factors associated with avoiding two important health services for people who use drugs-medications for treatment of opioid use disorder and syringe service programs-during the first year of the COVID-19 pandemic., Methods: Data come from two subsamples of people who use drugs who were active participants in one of nine cohort studies in Vancouver, British Columbia; Baltimore, Maryland; Los Angeles, California; Chicago, Illinois; and Miami, Florida. Participants were interviewed remotely about COVID-19-associated disruptions to healthcare. We estimated the association of demographic, social, and health factors with each outcome using logistic regression among 702 participants (medication analysis) and 304 participants (syringe service analysis.) Analyses were repeated, stratified by city of residence, to examine geographic variation in risk., Results: There were large differences between cities in the prevalence of avoiding picking up medications for opioid use disorder, with almost no avoidance in Vancouver (3%) and nearly universal avoidance in Los Angeles, Chicago, and Miami (>90%). After accounting for between-city differences, no individual factors were associated with avoiding picking up medications. The only factor significantly associated with avoiding syringe service programs was higher levels of self-reported worry about COVID-19., Conclusion: During the first year of the COVID-19 pandemic, geographic differences in service and policy contexts likely influenced avoidance of health and harm reduction services by people who use drugs in the United States and Canada more than individual differences between people., Competing Interests: Conflicts of interest Dr. Milloy holds the Canopy Growth professorship in cannabis science at the University of British Columbia, a position established through arm’s length gifts to the university from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia’s Ministry of Mental Health and Addictions. He has no financial relationships with the cannabis industry., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Data from the COVID-19 pandemic describes increases in drug use and related harms, especially fatal overdose. However, evidence is needed to better understand the pathways from pandemic-related factors to substance use behaviours. Thus, we investigated stockpiling drugs among people who use drugs (PWUD) in five cities in the United States and Canada., Methods: We used data from two waves of interviews among participants in nine prospective cohorts to estimate the prevalence and correlates of stockpiling drugs in the previous month. Longitudinal correlates were identified using bivariate and multivariate generalized linear mixed-effects modeling analyses., Results: From May 2020 to February 2021, we recruited 1873 individuals who completed 2242 interviews, of whom 217 (11.6%) reported stockpiling drugs in the last month at baseline. In the multivariate model, stockpiling drugs was significantly and positively associated with reporting being greatly impacted by COVID-19 (Adjusted Odds Ratio [AOR]= 1.21, 95% CI: 1.09-1.45), and at least daily use of methamphetamine (AOR = 4.67, 95% CI: 2.75-7.94) in the past month., Conclusions: We observed that approximately one-in-ten participants reported stocking up on drugs during the COVID-19 pandemic. This behaviour was associated with important drug-related risk factors including high-intensity methamphetamine use. While these correlations need further inquiry, it is possible that addressing the impact of COVID-19 on vulnerable PWUD could help limit drug stockpiling, which may lower rates of high-intensity stimulant use., Competing Interests: Conflicts of interest M-JM holds the Canopy Growth professorship in cannabis science at the University of British Columbia, a position established through arm’s length gifts to the university from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia’s Ministry of Mental Health and Addictions. He has no financial relationships with the cannabis industry., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: The overdose crisis in Canada has worsened since the emergence of the COVID-19 pandemic. Although this trend is thought to be driven in part by closures or reduced capacity of supervised consumption services (SCS), little is known about the factors that may impede access to such services during the COVID-19 pandemic among people who use drugs. This study sought to characterize the prevalence and correlates of having difficulty accessing SCS during the COVID-19 pandemic among people who use drugs in Vancouver, Canada., Methods: Cross-sectional data from two open prospective cohorts of people who use drugs were collected via phone or videoconferencing interviews conducted between July 2020 and November 2020. Multivariable logistic regression analyses were used to examine factors associated with experiencing difficulty accessing SCS., Results: Among the 428 people who use drugs who participated in the study, 223 (54.7%) self-identified as men and the median age was 51 years (1st to 3rd quartile: 42-58). A total of 58 (13.6%) participants reported experiencing difficulty accessing SCS. In a multivariable analysis, factors positively associated with difficulty accessing SCS included daily crystal methamphetamine use (Adjusted odds ratio [AOR] = 2.60; 95% confidence interval [CI] 1.28-5.30), active injection drug use (AOR = 4.06; 95% CI 1.38-11.90), recent non-fatal overdose (AOR = 2.45; 95% CI 1.24-4.85), and unstable housing (AOR = 2.14; 95% CI 1.08-4.23). Age was inversely associated with the outcome (AOR = 0.96; 95% CI 0.93-0.99) in multivariable analyses. The most commonly reported reasons for experiencing difficulty accessing SCS were: COVID-19-related site closure or shortened hours (42.9%) and having to wait too long to use a site (39.3%)., Conclusions: We found that people who use drugs with markers of structural vulnerability and drug-related risk were more likely to experience difficulty accessing SCS during the COVID-19 pandemic. These findings point to the need for strategies to support access to such services as part of pandemic response efforts., (© 2022. The Author(s).)

Background: Settings throughout Canada and the USA continue to experience crises of overdose death due to the toxic unregulated drug supply. Injecting drugs alone limits the potential for intervention and has accounted for a significant proportion of overdose deaths, yet the practice remains understudied. We sought to examine the practice of injecting alone among people who inject drugs (PWID) in Vancouver, Canada., Methods: Data were derived from two prospective cohorts of people who use drugs between June 2016 and November 2018. This analysis was restricted to participants who, in the previous 6 months, reported any injection drug use. Rates of injecting alone were categorized as always, usually, sometimes, or occasionally. We fit a multivariable generalized linear mixed model to identify factors associated with injecting drugs alone., Results: Among 1070 PWID who contributed 3307 observations, 931 (87%) reported injecting alone at least once during the study period. In total, there were 729 (22%) reports of always injecting alone, 722 (21.8%) usually, 471 (14.2%) sometimes, 513 (15.5%) occasionally, and 872 (26.4%) never. In a multivariable model, factors positively associated with injecting drugs alone included male sex (adjusted odds ratio [AOR] 1.69; 95% confidence interval [CI] 1.20-2.37), residence in the Downtown Eastside neighbourhood (AOR 1.43; 95% CI 1.08-1.91), binge drug use (AOR 1.36; 95% CI 1.08-1.72), and experiencing physical or sexual violence or both (AOR 1.43; 95% CI 1.00-2.03). Protective factors included Indigenous ancestry (AOR 0.71; 95% CI 0.52-0.98) and being in a relationship (AOR 0.30; 95% CI 0.23-0.39)., Conclusion: We observed that injecting alone, a key risk for overdose mortality, was common among PWID in Vancouver. Our findings underline the need for additional overdose prevention measures that are gender-specific, culturally appropriate, violence- and trauma-informed, and available to those who inject alone., (© 2022. The Author(s).)

Background: In the context of the ongoing opioid crisis in the United States and Canada, opioid agonist therapy (OAT) is the first-line treatment for opioid use disorder. However, there is growing concern regarding the increasing methamphetamine use among those on OAT, as well as the impact of such use may have on OAT retention and outcomes. We sought to identify the predictors of crystal methamphetamine initiation or re-initiation among people on OAT, in order to facilitate the development of effective preventive strategies., Methods: We employed multivariable generalized estimating equations to identify the predictors of crystal methamphetamine use initiation or re-initiation among those who were on OAT within two prospective cohorts in Vancouver, Canada between 2005 and 2020., Results: Of the 1281 participants receiving OAT, the median age was 43 years, and 59.2 % were male at baseline. During study follow-up, 564 (44.0 %) initiated or re-initiated crystal methamphetamine use while receiving OAT. In a multivariable model, a higher crystal methamphetamine use initiation or re-initiation rate was positively associated with younger age, unstable housing, unprotected sex, history of crystal methamphetamine use, as well as recent cocaine, prescription opioid, and unregulated opioid use (all p < 0.05)., Conclusions: We identified high and increasing rates of crystal methamphetamine use initiation or re-initiation among our sample of people on OAT. Intervention strategies including housing program referral, sexual risk reduction, and integrated treatment approaches targeting polysubstance use are urgently needed to reduce the risks associated with methamphetamine use as well as the co-use of methamphetamine and opioids., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: OxyContin was delisted from Canadian provincial drug formularies in March 2012 and replaced with a reformulated tamper-resistant form of oxycodone (i.e., OxyNeo). We assessed if delisting of OxyContin was associated with changes in the use of unregulated opioids and other substances among people who use opioids (PWUO)., Methods: Data were derived from two prospective cohort studies of people who use drugs in Vancouver, BC, Canada from 2006 to 2018. PWUO who had at least one follow-up visit before and after delisting of OxyContin were included. Outcomes of interest were self-reported regular (i.e., at least weekly) use of heroin, non-prescribed prescription opioids, cannabis, methamphetamine, crack cocaine, and powder cocaine during the previous six months. Using quasi-experimental interrupted time series, we fit generalized least squares models to assess participants' immediate and long-term substance use practices after the policy change., Results: We analyzed data from 1014 participants who contributed to 17457 visits during the study. Following the delisting of OxyContin, heroin use increased immediately by 5.17% (95% confidence intervals [CI]: 0.68 to 9.67) and over time by 0.47% (0.35 to 0.58) per month. Non-prescribed prescription opioid use increased immediately by 1.80% (0.10 to 3.50) and over time by 0.16% (0.12 to 0.19) per month. Cannabis use increased immediately by 4.37% (0.88 to 7.87) and over time by 0.11% (0.02 to 0.19) per month. Methamphetamine use did not increase immediately but increased over time by 0.10% (0.01 to 0.18) per month. Crack cocaine use decreased immediately by 6.13% (-10.94 to -1.69) but not significantly over time. Lastly, powder cocaine use did not increase immediately or over time., Conclusions: Delisting of OxyContin in BC was not associated with a reduction in unregulated opioid use among PWUO. Our findings point to a shift in substance use patterns of PWUO post-intervention and further highlight the unintended consequences of supply-reduction interventions in addressing the opioid epidemic., Competing Interests: Declarations of Interest M.K. and C.H. are supported by the Banting Postdoctoral Fellowship. M.K. was supported by Vanier Canada Graduate Scholarship and the Pierre Elliott Trudeau Foundation Doctoral Scholarship when the initial version was drafted. K.H. is supported by a Michael Smith Foundation for Health Research (MSFHR) Career Scholar Awards and CIHR New Investigator Award (MSH 141971). K.H. also holds the St. Paul's Hospital Chair in Substance Use Research and is supported in part by the St. Paul's Foundation and the NIDA (U01-DA038886). M.J.M. is supported by the US National Institutes of Health (U01-DA0251525). He is the Canopy Growth professor of cannabis science at the University of British Columbia, a position established through arms length gifts to the university from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia's Ministry of Mental Health and Addictions., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Although factors associated with completion of medical detoxification treatment for substance use disorders (SUD) are well described, there is limited information on barriers and facilitators to subsequent linkage to SUD treatment in the community. This study aimed to evaluate correlates of successful linkage to community SUD treatment on discharge., Methods: Data were drawn from 2 prospective cohorts of people who use unregulated drugs in Vancouver, Canada between December 2012 and May 2018. Multivariable generalized estimating equations were used to investigate factors associated with linkage to community SUD treatment in the 6-month period after attending detoxification treatment., Results: Of the 264 detoxification treatment encounters contributed by 178 people who use unregulated drugs, these were most often (n = 104, 39%) related to polysubstance use, and the majority (n = 174, 66%) resulted in subsequent linkage to community treatment. In the multivariable analysis, compared to attending detoxification treatment for opioid use, attending detoxification treatment for stimulants (adjusted odds ratio [AOR] = 0.23, 95% confidence interval [CI] : 0.10-0.51) and alcohol (AOR = 0.17, 95% CI: 0.06-0.54) were associated with lower odds of subsequent linkage to community treatment. Conversely, later calendar year of detoxification treatment remained associated with higher odds (AOR = 1.23, 95% CI: 1.06-1.42)., Conclusions: Only two-thirds of detoxification treatment encounters in Vancouver were subsequently linked to community SUD treatment, with those related to nonopioid substances being less likely. Findings suggest the need for tailored interventions for specific substances to improve linkage to SUD treatment in the community on discharge., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 American Society of Addiction Medicine.)

We sought to evaluate the effect of crack cocaine use frequency on HIV disease severity among HIV-positive people who use unregulated drugs (PWUD). We analyzed data from the ACCESS study, an open prospective cohort of HIV-positive PWUD including comprehensive HIV clinical monitoring in a setting with no-cost healthcare. Multivariable generalized linear mixed-effects models were used to estimate the independent effect of time-updated crack cocaine use frequency on HIV disease severity, adjusting for ART exposure and relevant confounders. In multivariable adjusted models, daily or greater frequency of crack cocaine use was significantly associated with higher VACS Index scores (β = 0.8, 95% confidence interval: 0.1, 1.5) as compared to none. Our finding suggests that daily or greater frequency of crack cocaine use exacerbates HIV disease severity independent of ART exposure. The observed effect may reflect an underlying biological mechanism or other factors linked with crack cocaine use; further investigation is warranted., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The Assessing Economic Transitions (ASSET) study was established to identify relationships between economic engagement, health and well-being in inner-city populations given that research in this area is currently underdeveloped. This paper describes the objectives, design, and characteristics of the ASSET study cohort, an open prospective cohort which aims to provide data on opportunities for addressing economic engagement in an inner-city drug-using population in Vancouver, Canada. Participants complete interviewer-administered surveys quarterly. A subset of participants complete nested semi-structured qualitative interviews semi-annually. Between April 2019 and May 2022, the study enrolled 257 participants ages 19 years or older (median age: 51; 40% Indigenous, 11.6% non-Indigenous people of colour; 39% cis-gender women, 3.9% transgender, genderqueer, or two-spirit) and 41 qualitative participants. At baseline, all participants reported past daily drug use, with 27% currently using opioids daily, and 20% currently using stimulants daily. In the three months prior to baseline, more participants undertook informal income generation (75%) than formal employment (50%). Employed participants largely had casual jobs (42%) or jobs with part-time/varied hours (35%). Nested qualitative studies will focus on how inner-city populations experience economic engagement. The resulting evidence will inform policy and programmatic initiatives to address socioeconomic drivers of health and well-being.

Background: People who use unregulated drugs (PWUD) often face significant barriers to-and thereby avoid seeking-health care. In Vancouver, Canada, a neighborhood-wide health care system reform began in 2016 to improve health care delivery and quality. In the wake of this reform, we sought to determine the prevalence of health care avoidance and its association with emergency department use among PWUD in this setting and examine patient-reported nonmedical qualities of health care ("responsiveness")., Methods: The study derived data from two prospective cohort studies of community-recruited PWUD in Vancouver in 2017-18. Responsiveness was ascertained by the World Health Organizations' standardized measurements and we evaluated seven domains of responsiveness (dignity, autonomy, communication, confidentiality, prompt attention, choice of provider, and quality of basic amenities). The study used Pearson chi-squared test to examine differences in responsiveness between those who did and did not avoid care. The study team used multivariable logistic regression to determine the relationship between care avoidance due to past mistreatment and emergency department use, adjusting for potential confounders., Results: Among 889 participants, 520 (58.5%) were male, 204 (22.9%) reported avoiding health care, most commonly for chronic pain (47.4%). Overall, 6.6% to 36.2% reported suboptimal levels (i.e., not always meeting the expected quality) across all seven measured domain of responsiveness. Proportions reporting suboptimal qualities were significantly higher among those who avoided care than those who did not across all domains, including care as soon as wanted (51.0% vs. 31.8%), listened to carefully (44.1% vs. 20.4%), and involved in health care decision-making (27.9% vs. 12.7%) (all p < 0.05). In multivariable analyses, avoidance of health care was independently associated with self-reported emergency department use (adjusted odds ratio = 1.49; 95% confidence interval:1.01-2.19)., Conclusion: We found that almost a quarter of our sample of PWUD avoided seeking health care due to past mistreatment, and all seven measured domains of responsiveness were suboptimal and linked with avoidance. Individuals who reported avoidance of health care were significantly more likely to report emergency department use. Multi-level interventions are needed to remedy the suboptimal qualities of health care and thereby reduce care avoidance., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Across the United States and Canada drug-related Good Samaritan laws (GSLs) have been enacted to encourage observers of acute drug overdose events to contact emergency medical services (EMS) without fear of legal repercussions. However, little is known about the working knowledge of GSLs among people who use illicit drugs (PWUD). We sought to evaluate the prevalence and factors associated with accurate knowledge of a GSL among PWUD in Vancouver, Canada, 1 year after the GSL was enacted., Method: We used data from participants in three community-recruited prospective cohort studies of PWUD interviewed between June and November 2018. Multivariable logistic regression was used to identify factors associated with accurate knowledge of the GSL., Results: Among 1,258 participants, including 760 males (60%), 358 (28%) had accurate knowledge of the GSL. In multivariable analyses, participants who reported ever having a negative police encounter (defined as being stopped, searched, or detained by the police) were less likely to have accurate knowledge of the GSL (adjusted odds ratio [AOR] = 0.70; 95% CI [0.54, 0.90]), while those involved in drug dealing were more likely to have accurate knowledge of the GSL (AOR = 1.50; 95% CI [1.06, 2.06])., Discussion: Despite having been enacted for a full year, approximately three quarters of participants did not have accurate GSL knowledge, warranting urgent educational efforts among PWUD. Additional research is needed to understand whether GSLs can mitigate the fears of legal repercussions among those engaged in drug dealing and with past negative experiences with the police.

Objectives: Opioid agonist treatment (OAT) has been shown to improve certain HIV-related treatment measures among people with HIV (PHIV) with opioid use disorder (OUD). However, there is limited data on the impacts of OAT along the whole HIV cascade of care., Design and Methods: Using data from an ongoing cohort of PHIV who use drugs in Vancouver, Canada, we used cumulative link mixed-effects models to estimate the independent effect of OAT on achieving progressive steps in the HIV cascade among participants using unregulated opioids daily, after adjusting for confounders., Results: Between 2005 and 2017, we recruited 639 PHIV regularly using opioids (median age 42 years, 59% male, 56% White), of whom 70% were on OAT at their baseline visit. Engagement in OAT showed a nonsignificant trend with higher linkage to HIV care (adjusted partial proportional odds ratio [APPO] = 1.75, 95% confidence interval [CI]: 0.83-3.69), and significantly higher cumulative odds of successfully achieving subsequent HIV cascade steps: on ART (APPO = 3.85, 95% CI: 2.33-6.37); adherent to ART (APPO = 3.15, 95% CI: 2.15-4.62); and HIV viral suppression (APPO = 2.18, 95% CI: 1.51-3.14)., Conclusions: This study found a high level of OAT engagement among PHIV using unregulated opioids and that OAT engagement resulted in significantly increased progression through some of the higher steps of the HIV cascade. While these findings are encouraging, they highlight the need to reach populations off OAT to maximize the clinical and community-level benefits of ART., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

People who use illicit drugs (PWUD) face increased exposure to the criminal justice system and disproportionate burdens of HIV infection. This article investigated the effects of incarceration on HIV cascade of care-related measures in a setting with a community-wide seek, test, treat, and retain (STTR) initiative. Using a multivariable logistic regression analysis of 935 HIV-positive PWUD between 2005 and 2017, this article showed a negative relationship between periods of incarceration and two measures of engagement in clinical care for HIV among PWUD: recent dispensation of antiretroviral therapy and suppression of HIV viral load. These findings suggest the benefits of STTR-based efforts are limited by exposure to the criminal justice system and highlight the need for additional supports for PWUD with HIV exposed to the criminal justice system.

Objectives: Owing to advances in antiretroviral therapy (ART), we re-examined minimum ART adherence levels necessary to achieve sustained HIV-1 viral load (VL) suppression among people with HIV who use drugs (PHIV-PWUD)., Design and Methods: We used data from ACCESS, a community-recruited prospective cohort of PHIV-PWUD in Vancouver, Canada. We calculated adherence using the proportion of days of ART dispensed in the year before each VL measurement. We used generalized linear mixed-effects models to identify adherence- and ART regimen-related correlates of VL suppression (<200 copies/ml). We employed probit regression models and generated dose-response curves to estimate the minimum adherence level needed to produce VL suppression in 90% of measures, stratified by regimen and calendar-year., Results: Among 837 ART-exposed PHIV-PWUD recruited between 1996 and 2017, the overall estimated adherence level necessary to achieve 90% VL suppression was 93% (95% confidence interval [CI]: 90-96). This differed by regimen: 69% (95% CI: 45-92) for integrase inhibitor (INSTI)-, 96% (95% CI: 92-100) for boosted protease inhibitor (bPI)-, and 98% (95% CI: 91-100) for non-nucleoside reverse transcriptase inhibitor-based regimens. In multivariable analysis, INSTI-based regimens were positively associated with VL suppression (vs. bPIs), while un-boosted PIs and other regimens were negatively associated. We observed a decreasing temporal trend of estimated adherence necessary for 90% VL suppression, dropping to 64% (95% CI: 50-77) during 2016-2017., Conclusion: Although high levels of ART adherence were necessary to achieve consistent VL suppression, the minimum necessary adherence levels decreased over time. Overall, INSTI-based regimens performed the best, suggesting that they should be preferentially prescribed to PHIV-PWUD., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: We were engaged by policy stakeholders to undertake a scoping review of cannabis measurement instruments to inform the evaluation of cannabis legalization impacts. We identified instruments employed in population-based or clinical research to screen and assess cannabis use, including measurement properties. We also identified the content domains included in each instrument and gaps in the measurement of key priority areas as established by policy stakeholders., Methods: We followed PRISMA and conducted searches on MEDLINE, PsycINFO, Web of Science, EMBASE, HAPI, Scopus and grey literature. We included publications from the past 15 years that reported the use of an instrument to measure cannabis use. Six study team members calibrated screening and data abstraction, independently identified records and abstracted data., Results: Across 915 included publications, we identified 187 unique instruments covering seven content domains and 35 subdomains. The most identified instruments were the Composite International Diagnostic Interview, the Timeline Follow-Back and the National Epidemiologic Survey on Alcohol and Related Conditions (109/915; 91/915; 64/915). The Canadian Cannabis Survey addressed the most subdomains (22/35). Frequency of use, prevalence of use, and mental health impacts were the most addressed subdomains (110/187; 94/187; 67/187) and storage, growing cannabis, and second-hand exposure were the least addressed (1/187; 4/187; 6/187)., Conclusion: This research identified instruments and domains critical to the assessment of public health impacts of cannabis legalization, which can facilitate the harmonization of measures to inform policy development. Future research should develop new instruments for less commonly-addressed constructs and thoroughly explore psychometric properties of existing instruments., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objectives: Driven by an increasingly toxic drug supply, drug toxicity deaths in the United States and Canada have risen to unprecedented levels during the COVID-19 pandemic. This study aimed to characterize the prevalence of and the factors associated with a perceived decline in the quality of drugs during the COVID-19 pandemic among community-recruited cohorts of PWUD in Vancouver, Canada., Methods: Data collection took place between July and November 2020. In adherence with COVID-19 safety protocols, questionnaires were administered by interviewers through remote means (e.g., phone or videoconference). Using multivariable logistic regression, we characterized the prevalence of and factors associated with a perceived decline in drug quality during the start of the COVID-19 pandemic in Vancouver, Canada., Results: Of the 738 individuals included in this analysis, 272 (36.9%) reported that the quality of drugs declined during the COVID-19 pandemic. In multivariable analysis, perceived decline in the quality of drugs was significantly associated with: recent non-fatal overdose (adjusted odds ratio [AOR]=2.01, 95% Confidence Interval [CI]: 1.29-3.15), at least weekly injection drug use (AOR=1.94, 95% CI: 1.40-2.71), at least weekly crack use (AOR=1.61, 95%CI: 1.10-2.36), and at least weekly crystal methamphetamine use (AOR=1.46, 95%CI: 1.03-2.08)., Discussion: Over a third of PWUD perceived that the quality of drugs declined during the COVID-19 pandemic and these individuals were significantly more likely to report experiencing a recent non-fatal overdose, engaging in frequent injection drug and stimulant use. Study findings indicate the need for interventions to address the toxic drug supply, including providing a regulated supply., (Copyright © 2022 Elsevier B.V. All rights reserved.)

We sought to evaluate the impact of homelessness on HIV disease progression among people who use unregulated drugs (PWUD) living with HIV and test if this association was mediated by adherence to antiretroviral therapy (ART). We applied general linear mixed-effects modeling to estimate the longitudinal relationship between homelessness and the Veterans Aging Cohort Study (VACS) Index, a validated measure of HIV disease progression that predicts all-cause mortality, among a prospective cohort of PWUD. In a longitudinal model adjusted for ART adherence, homelessness was significantly associated with increased VACS Index scores and 16% of the association was mediated by ART adherence. These findings indicate that homelessness was a significant risk factor for HIV disease progression and this association was marginally mediated by ART adherence. Future studies are needed to quantify the other mechanisms (e.g., food insecurity, mental health) by which homelessness increases mortality risk among PWUD living with HIV., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

A robust evidence-base describes the beneficial association between opioid agonist therapy (OAT) and HIV-related outcomes among people living with HIV and opioid use disorder. While some evidence suggests the stabilizing effect of OAT on antiretroviral therapy (ART) treatment engagement, less is understood about the potential for an inverse relationship. We sought to examine the relationship between transitions in ART engagement and transitions onto OAT. We used data from a prospective cohort of people living with HIV who use drugs in Vancouver, Canada-a setting with no-cost access to ART and low or no-cost access to OAT among low-income residents. Restricting the sample to those who reported daily or greater opioid use, we used generalized linear mixed-effects models to estimate the relationships between our primary outcome of transitions onto OAT (methadone or buprenorphine/naloxone) and transitions (1) onto ART and (2) into ART adherence. Subsequent analyses assessed the temporal sequencing of transitions. Between 2005 and 2017, among 433 participants, 48.3% reported transitioning onto OAT at least once. In concurrent analyses, transitions onto ART were positively and significantly associated with transitions onto OAT. Temporal sequencing revealed that transitions into OAT were also positively and significantly associated with subsequent transitions onto ART. OAT's potential to facilitate the uptake of ART points to the continued need to scale-up low-threshold, client-centered substance use services integrated alongside HIV care., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: When the novel coronavirus pandemic emerged in March 2020, many settings across Canada and the USA were already contending with an existing crisis of drug overdoses due to the toxic unregulated drug supply. In response, the Canadian province of British Columbia (BC) released innovative risk mitigation prescribing (RMP) guidelines for medical professionals to prescribe pharmaceutical alternatives to unregulated drugs in an effort to support the self-isolation of people who use unregulated drugs (PWUD) in preventing both SARS-CoV-2 virus infection and overdoses. We sought to assess the level of awareness of RMP and identify factors associated with this awareness among PWUD in Vancouver, BC., Methods: Cross-sectional data were derived from participants enrolled in three community-recruited prospective cohort studies of PWUD in Vancouver, interviewed between July and November 2020. Multivariable logistic regression analysis was used to identify factors associated with awareness of RMP., Results: Among 633 participants, 302 (47.7%) had heard of RMP. Of those 302 participants, 199 (65.9%) had never tried to access RMP services, ten (3.3%) made an unsuccessful attempt to access RMP, and 93 (30.8%) received RMP. In the multivariable analysis, participants who had awareness of RMP guidelines were more likely to self-identify as white (adjusted odds ratio [AOR] = 1.47; 95% confidence interval [CI]: 1.01, 2.13), to have completed secondary school education or higher (AOR = 1.67; 95% CI: 1.16, 2.39), to have used drugs at a supervised consumption or overdose prevention site in the past six months (AOR = 1.66; 95% CI: 1.10, 2.52), and to have received opioid agonist therapy as treatment for opioid use disorder in the past six months (AOR = 1.51; 95% CI: 1.02, 2.24)., Conclusion: At least four months after the release of the guidelines, RMP was known to less than half of our study participants, warranting urgent educational efforts for PWUD, particularly among racialized groups and those who were not accessing other harm reduction services. Furthermore, the majority of participants who were aware of RMP guidelines had never tried to access the service, suggesting the need to improve perceived accessibility and knowledge of eligibility criteria., (© 2022. The Author(s).)

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., (© 2022. The Author(s).)

Background and Aims: In response to a dramatic rise in overdose deaths due to injection drug use, there was a rapid scale-up of low-threshold supervised injection services (SIS), termed 'overdose prevention sites' (OPS), in Vancouver, Canada in December 2016. We measured the potential impact of this intervention on SIS use and related health outcomes among people who inject drugs (PWID)., Design: Segmented regression analyses of interrupted time series data from two community-recruited prospective cohorts of PWID from January 2015 to November 2018 were used to measure the impact of the OPS scale-up on changes in SIS use, public injection, syringe sharing and addiction treatment participation, controlling for pre-existing secular trends., Setting: Vancouver, Canada., Participants: Of 745 PWID, 292 (39.7%) were women, 441 (59.6%) self-reported white ancestry and the median age was 47 years (interquartile range = 38, 53) at baseline., Measurements: Immediate (i.e. step level) and gradual (i.e. slope) changes in the monthly proportion of participants who self-reported past 6-month SIS use, public injection, syringe sharing and participation in any form of addiction treatment., Findings: Post OPS expansion, the monthly prevalence of SIS use immediately increased by an estimated 6.4% [95% confidence interval (CI) = 1.7, 11.2] and subsequently further increased by an estimated 0.7% (95% CI = 0.3, 1.1) per month. The monthly prevalence of addiction treatment participation immediately increased by an estimated 4.5% (95% CI = 0.5, 8.5) following the OPS expansion, while public injection and syringe sharing were estimated to immediately decrease by 5.5% (95% CI = 0.9, 10.0) and 2.5% (95% CI = 0.5, 4.6), respectively. Findings were inconclusive as to whether or not an association was present between the intervention and subsequent gradual changes in public injection, syringe sharing and addiction treatment participation., Conclusions: Scaling-up overdose prevention sites in Vancouver, Canada in December 2016 was associated with immediate and continued gradual increases in supervised injection service engagement and immediate increases in related health benefits., (© 2021 Society for the Study of Addiction.)

Objectives: Methamphetamine use is rising globally and we have limited treatments for this. Subgroups within the diverse methamphetamine-using population may have distinct treatment needs. Among a community-recruited sample of people who use crystal methamphetamine, we aimed to identify subgroups and characterize their overdose risk and access to addiction care., Methods: Data from prospective cohorts of people who use drugs in Vancouver, Canada from 2014 to 2018 were used to conduct a repeated measures latent class analysis among participants who used crystal methamphetamine. Multivariable generalized estimating equations models were fit to determine the associated factors., Results: Among 824 eligible participants, a five-class model was identified as the best fit: (1) primary stimulant use (15.7%); (2) women engaged in sex work and opioid use (21.4%); (3) street income generation and opioid use (31.6%); (4) opioid agonist therapy (OAT) patients (22.3%); and (5) men who have sex with men (9.0%). In multivariable analyses, compared to the primary stimulant use group, non-fatal overdose was positively associated with street income generation (adjusted odds ratio [AOR] = 1.49, 95% confidence interval [95% CI]=1.30-1.71), sex work (AOR = 1.38, 95% CI=1.20-1.59) and OAT (AOR = 1.22, 95% CI=1.06-1.41) subgroups; engagement in non-OAT addiction care was negatively associated with street income generation (AOR = 0.81, 95% CI=0.68-0.97) and sex work (AOR = 0.78, 95% CI=0.63-0.98) subgroups., Discussion: Socioeconomically marginalized subgroups with opioid and crystal methamphetamine co-use were at highest risk of non-fatal overdose and had poorer access to addiction care, highlighting the need for tailored interventions., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Buprenorphine-naloxone (BUP-NX) is a first-line treatment for opioid use disorder and has a superior safety profile compared to other forms of opioid agonist therapy. In Canada, restrictions on BUP-NX prescribing were relaxed in 2016, which may have had an effect on rates of diversion and non-prescribed use. We sought to longitudinally examine the reported availability and use of non-prescribed BUP-NX among people who use drugs (PWUD) in an urban Canadian setting., Methods: We collected data from two linked prospective cohorts of PWUD in Vancouver, Canada, and examined self-reported availability and use of non-prescribed BUP-NX over time. We used a multivariable generalized estimating equations model to identify trends and factors associated with the immediate availability (i.e., within 10 min) of non-prescribed BUP-NX., Results: Among 1617 participants between 2014 and 2020, the immediate availability of non-prescribed BUP-NX increased from 16% to 63% (p<0.001). In the multivariable analysis, factors independently associated with immediate BUP-NX availability included calendar year (adjusted odds ratio = 1.19, 95% confidence interval: 1.15-1.23), along with a number of other variables suggestive of more severe substance use disorders. Only 17 participants ever reported use of non-prescribed BUP-NX., Conclusions: We observed that BUP-NX has become increasingly available in the unregulated drug supply in recent years but its use has remained infrequent in this setting. These results suggest that relaxed restrictions on BUP-NX prescribing have not been a major driver of increased non-prescribed use in this population., Competing Interests: Declarations of Interest The authors report no conflicts of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Research into the therapeutic and naturalistic uses of psychedelics for improving outcomes related to mental health disorders has generated increasing interest in recent years. While controlled clinical trials of psychedelics have signaled benefits for treating substance use disorders, this area has not been well studied in the context of naturalistic psychedelic use. This study sought to investigate the possible relationship between recent naturalistic psychedelic use and subsequent daily illicit opioid use among people who use drugs (PWUD)., Methods: Data (2006-2018) were drawn from three harmonized prospective cohorts of community-recruited PWUD in Vancouver, Canada. We used multivariable generalized linear mixed-effects modeling (GLMM) to estimate the independent association between psychedelic use and subsequent daily illicit opioid use., Results: Among 3813 PWUD at baseline, 1093 (29%) reported daily use of illicit opioids and 229 (6%) reported psychedelic use in the past six months. Over study follow-up after adjusting for a range of potential confounders, psychedelic use remained independently associated with a significantly reduced odds of subsequent daily opioid use (Adjusted Odds Ratio: 0.45; 95% Confidence Interval: 0.29 to 0.70)., Conclusion: While confirmation in other settings is required, these findings align with growing evidence that psychedelic use may be associated with detectable reductions in subsequent substance use including illicit opioid use., Competing Interests: Declarations of Interest Drs. Argento, Mackay and Christie are consultants to Numinus Wellness, a Canadian mental health company interested in the use of psychedelics for medical purposes. Numinus Wellness was not involved in the collection of data, the writing of this manuscript, or the decision to submit findings for publication. M-J Milloy is the Canopy Growth professor of cannabis science at the University of British Columbia, a position created by unstructured gifts to the university from Canopy Growth, a licensed producer of cannabis, and the Government of British Columbia's Ministry of Mental Health and Addictions. The University of British Columbia has also received unstructured funding from NG Biomed Ltd to support him., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Despite increasing prevalence of illicit fentanyl use in the US and Canada, preference for fentanyl over other illicit opioids has not been fully characterized. Therefore, we sought to describe changes in illicit opioid preferences over time among people who inject drugs (PWID). Methods: Data were obtained from two prospective cohort studies between 2017 and 2018. Trends in opioid preference over time were examined using bivariable generalized estimating equation (GEE) analysis. Multivariable models were used to identify factors associated with fentanyl preference. Results: Among 732 eligible participants, including 425 (58%) males, the prevalence of preference for fentanyl increased from 4.4% in 2017 to 6.6% in 2018 (Odds Ratio [OR] = 1.27, 95% Confidence Interval [CI]: 1.05-1.52). In a multivariable analysis, younger age (Adjusted Odds Ratio [AOR] = 0.94, 95% CI: 0.92-0.96) and daily crystal methamphetamine injection (AOR = 1.68, 95% CI: 1.01-2.78) were independently associated with preference for fentanyl. The most common reasons for preferring fentanyl included "better high than other opioids" (45%), and "lasts longer than heroin" (27%). Conclusions: The current study has demonstrated that preference for fentanyl has been increasing over time among our sample of PWID who use opioids. Further work is needed to clarify risk factors surrounding transitions to illicit fentanyl.

Background: While preliminary evidence has begun to document intentional use of one substance to reduce the use of another, the phenomenon of drug substitution among people who use illicit opioids remains understudied. Therefore, we sought to estimate the prevalence and correlates of intentional substance use to reduce illicit opioid use among persons who use drugs (PWUD)., Methods: We analysed data from three prospective cohorts of PWUD in Vancouver, Canada, using multivariable generalized estimating equations (GEE)., Results: Between June 2012 and June 2016, 1527 participants were recruited and contributed 4991 interviews. Of those, 336 (22%) illicit opioid-using participants self-reported substitution to reduce illicit opioid use at least once during study period contributing 467 (9.4%) interviews. Among those interviews, substances substituted for opioids were alcohol (15 participants, 3.2%), stimulants (235, 50.3%), cannabis (129, 27.6%), benzodiazepines (21, 4.5%), and others (20, 4.3%). In multivariable GEE model adjusted for socio-demographic factors, reporting substitution to reduce illicit opioid use was positively associated with greater likelihood of daily cannabis use (Adjusted Odds Ratio = 1.56, 95% Confidence Interval: 1.24-1.96]., Conclusions: While daily cannabis use was associated with reporting opioid substitution attempts, additional study is needed to examine potential of cannabis/cannabinoids to reduce illicit opioid use.

The United States and Canada are experiencing an opioid overdose crisis driven largely by exposure to fentanyl (a potent synthetic opioid), with little known about fentanyl exposure among HIV-positive people who use unregulated drugs (PWUD). We sought to estimate the prevalence and correlates of fentanyl exposure among a community-recruited sample derived from a prospective cohort study of HIV-positive PWUD in Vancouver, Canada. Generalized linear mixed-effects analyses were used to identify longitudinal factors associated with a fentanyl-positive urine drug screen test. Between June 2016-November 2017, 456 participants were recruited and contributed 1007 observations. At baseline, 96% of participants were ART-exposed, 72% had an HIV viral load (VL) <50 copies/mL and 21% had a fentanyl-positive test. Longitudinally, fentanyl-positive tests were characterized by: younger participant age (Adjusted Odds Ratio [AOR] = 0.45), recent non-fatal overdose (AOR = 2.30), engagement in opioid agonist therapy (AOR = 1.91), and at least daily heroin injection (AOR = 11.27). CD4+ cell count was negatively associated with fentanyl urine positivity (AOR = 0.92) (all p  < 0.05). We identified several risk factors for overdose linked to fentanyl exposure among this sample, although no link with HIV treatment engagement or detectable HIV VL. Innovative strategies are needed to reduce the harmful effects of the contaminated unregulated drug supply experienced by PWUD.