Vancouver Injection Drug Users Study Research Articles

The impact of the COVID-19 pandemic on access to supervised consumption programs

BackgroundSupervised 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.MethodsBetween 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.ResultsAmong 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).ConclusionsApproximately 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.

A gender comparative analysis of post-traumatic stress disorder among a community-based cohort of people who use drugs in Vancouver, Canada

BackgroundWhile exposure to traumatic events and subsequent post-traumatic stress disorder (PTSD) are common among people who use drugs (PWUD), little is known about gender-based differences associated with PTSD in this population. We explore gender-based differences in factors associated with a probable PTSD diagnosis in a cohort of PWUD from Vancouver, Canada. MethodsData were collected through the Vancouver Injection Drug Users Study (VIDUS) and the AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS), two community-recruited cohorts of PWUD. Participants were administered the PTSD Checklist for DSM-5. Multivariable logistic regression was used to investigate social-structural factors and substance use patterns and behaviours associated with a probable PTSD diagnosis, stratified by self-identified gender. PTSD symptom clusters and brief descriptions of the worst traumatic event experienced were also reported. ResultsBetween December 2016 and December 2018, of 797 eligible participants, 295 (37.0%) identified as women. PTSD was more commonly reported in women compared to men (53.2% vs. 31.5%, p < 0.001). In multivariable analysis involving men, no correlates were associated with PTSD. In multivariable analysis involving women, PTSD was positively associated with exposure to violence (AOR: 3.66; 95%CI: 1.14–11.72), daily stimulant use (AOR: 2.32; 95%CI: 1.32–4.08) and heavy alcohol use (AOR: 3.84; 95%CI: 1.84–8.00), and negatively associated with being in a stable relationship (AOR: 0.46; 95%CI: 0.25–0.84). ConclusionsGender-based differences in PTSD diagnosis among a cohort of PWUD point to the need to develop gender-focused and trauma-informed health and social services to meet the immediate needs of PWUD living with PTSD.

Overdose Risk and Acquiring Opioids for Nonmedical Use Exclusively from Physicians in Vancouver, Canada

Background A primary response to the alarming rise in overdose and mortality due to nonmedical prescription opioid (PO) use has been to restrict opioid prescribing; however, little is known about the relationship between obtaining opioids from a physician and overdose risk among people who use POs nonmedically and illicit street drugs. Objectives: Investigate the relationship between non-fatal overdose and acquiring POs exclusively from physicians for the purposes of engaging in nonmedical PO use. Methods: Data were collected between 2013 and 2016 among participants in two harmonized prospective cohort studies of people who use drugs in Vancouver: the At-Risk Youth Study (ARYS) and the Vancouver Injection Drug Users Study (VIDUS). Analyses were restricted to participants who engaged in nonmedical PO use and used generalized estimating equations. Results: Among 599 participants who used POs nonmedically, 82 (14%) individuals reported acquiring POs exclusively from a physician and 197 (33%) experienced a non-fatal overdose at some point over the study period. Acquiring POs exclusively from physicians was significantly and negatively associated with non-fatal overdose in the bivariate analysis (Odds Ratio = 0.60, 95% Confidence Interval (CI): 0.39–0.94) but not the final multivariate analysis (Adjusted Odds Ratio =0.87, 95% CI: 0.53–1.44). Conclusions: Compared to individuals who acquired POs from friends or the streets, participants who acquired POs exclusively from a physician were not at an increased risk of non-fatal overdose. Although responsible opioid prescribing is an important priority, additional strategies to address nonmedical PO use are urgently needed to reduce overdose and related morbidity and mortality.

An age-based analysis of nonmedical prescription opioid use among people who use illegal drugs in Vancouver, Canada

BackgroundNonmedical prescription opioid use (NMPOU) is a serious public health problem in North America. At a population-level, previous research has identified differences in the prevalence and correlates of NMPOU among younger versus older age groups; however, less is known about age-related differences in NMPOU among people who use illegal drugs.MethodsData were collected between 2013 and 2015 from two linked prospective cohort studies in Vancouver, Canada: the At-Risk Youth Study (ARYS) and the Vancouver Injection Drug Users Study (VIDUS). Factors independently associated with NMPOU among younger (ARYS) and older (VIDUS) participants were examined separately using bivariate and multivariate generalized estimating equations.ResultsA total of 1162 participants were included. Among 405 eligible younger participants (Median age = 25; Inter-Quartile Range [IQR]: 22–28), 40% (n = 160) reported engaging in NMPOU at baseline; among 757 older participants (Median age = 48, IQR: 40–55), 35% (n = 262) reported engaging in NMPOU at baseline. In separate multivariate analyses of younger and older participants, NMPOU was positively and independently associated with heroin use (younger: Adjusted Odds Ratio [AOR] = 3.12, 95% Confidence Interval [CI]: 2.08–4.68; older: AOR = 2.79, 95% CI: 2.08–3.74), drug dealing (younger: AOR = 2.22, 95% CI: 1.58–3.13; older: AOR = 1.87, 95% CI: 1.40–2.49), and difficulty accessing services (younger: AOR = 1.47, 95% CI: 1.04–2.09; older: AOR = 1.74, 95% CI: 1.32–2.29). Among the youth cohort only, NMPOU was associated with younger age (AOR = 1.12, 95% CI: 1.05–1.19), crack use (AOR = 1.56, 95% CI: 1.06–2.30), and binge drug use (AOR = 1.41, 95% CI: 1.00–1.97); older participants who engaged in NMPOU were more likely to report crystal methamphetamine use (AOR = 1.97, 95% CI: 1.46–2.66), non-fatal overdose (AOR = 1.76, 95% CI: 1.20–2.60) and sex work (AOR = 1.49, 95% CI: 1.00–2.22).DiscussionThe prevalence of NMPOU is similar among younger and older people who use drugs, and independently associated with markers of vulnerability among both age groups. Adults who engage in NMPOU are at risk for non-fatal overdose, which highlights the need for youth and adult-specific strategies to address NMPOU that include better access to health and social services, as well as a range of addiction treatment options for opioid use. Findings also underscore the importance of improving pain treatment strategies tailored for PWUD.

HIV Serostatus and Having Access to a Physician for Regular Hepatitis C Virus Care Among People Who Inject Drugs.

People who inject drugs (PWIDs) and who are living with HIV and hepatitis C virus (HCV) infection are vulnerable to a range of health-related harms, including liver cirrhosis, hepatocellular carcinoma, and death. There is limited evidence describing how HIV serostatus shapes access to a physician for regular HCV care among PWID. Data were collected through the Vancouver Injection Drug Users Study (VIDUS), the AIDS Care Cohort to evaluate Exposure to Survival Services (ACCESS), and the At-Risk Youth Study (ARYS), 3 prospective cohorts involving people who use illicit drugs in Vancouver, Canada, between 2005 and 2015. Using generalized estimating equations, we examined the relationship between HIV-seropositivity and having access to a physician for regular HCV care. We conducted a mediation analysis to examine whether this association was mediated by increased frequency of engagement in health care. In total, 1627 HCV-positive PWID were eligible for analysis; 582 (35.8%) were HIV-positive at baseline; and 31 (1.9%) became HIV-positive during follow-up. In multivariable analyses, after adjusting for a range of confounders, HIV serostatus [adjusted odds ratio = 1.99; 95% confidence interval: 1.77 to 2.24] was significantly associated with having access to HCV care. Approximately 26% of the effect was due to mediation. Our results demonstrate a positive relationship between HIV-seropositivity and having access to a physician for regular HCV care, which is partially explained through increased frequency of engagement in health care. These findings highlight the need to address patterns of inequality in access to HCV care among PWID.

Residential eviction and exposure to violence among people who inject drugs in Vancouver, Canada

BackgroundPeople who inject drugs (PWID) experience markedly elevated rates of physical and sexual violence, as well as housing instability. While previous studies have demonstrated an association between homelessness and increased exposure to violence among PWID, the relationship between residential eviction and violence is unknown. We therefore sought to examine the association between residential eviction and experiencing violence among PWID in Vancouver, Canada. MethodsData were derived from two open prospective cohort studies of PWID: the Vancouver Injection Drug Users Study (VIDUS) and the AIDS Care Cohort to evaluate Exposure to Survival Services (ACCESS). We used generalized estimating equations (GEE) to estimate the relationship between residential eviction and experiencing violence among male and female PWID, respectively. ResultsBetween June 2007 and May 2014, 1689 participants were eligible for the analysis, contributing a median of 5.5 years of follow-up. Of these, 567 (33.6%) were female. In total, 259 (45.7%) of females and 566 (50.4%) of males experienced at least one incident of violence over the study period. In multivariable GEE models, residential eviction was independently associated with greater odds of experiencing violence among both females (Adjusted Odds Ratio [AOR]=2.09; 95% confidence interval [CI]: 1.39–3.13) and males (AOR=1.95; 95% CI=1.49–2.55), after adjustment for potential confounders. ConclusionResidential eviction was independently associated with an increased likelihood of experiencing violence among both male and female PWID. These findings point to the need for evidence-based social-structural interventions to mitigate housing instability and violence among PWID in this setting.

Benzodiazepine Use and Hepatitis C Seroconversion in a Cohort of Persons Who Inject Drugs.

To examine the relationship between benzodiazepine (BZD) use and HCV seroconversion in 2 linked prospective cohorts of persons who inject drugs (PWID). We examined prospective cohorts of 440 PWID (baseline BZD users: n = 102; 23.2%) from the AIDS Care Cohort to Evaluate Access to Survival Services (ACCESS) and the Vancouver Injection Drug Users Study (VIDUS) cohorts, followed-up from 1996 to 2013 in Vancouver, Canada. At baseline, the prevalence of HCV was higher among those who used BZD (80.5% vs 61.5%; P < .001). After adjustment, BZD use remained independently associated with increased rates of HCV seroconversion (adjusted rate ratio = 1.67; 95% confidence interval = 1.05, 2.66). BZD use is independently associated with HCV seroconversion in a population of PWID.

Effect of low-threshold methadone maintenance therapy for people who inject drugs on HIV incidence in Vancouver, BC, Canada: an observational cohort study

HIV infection in people who inject drugs (PWID) is an international public health concern. We aimed to assess the effect of methadone maintenance therapy on HIV incidence in PWID in Vancouver, BC, Canada, where methadone is widely available through family physicians' offices and dispensed by community pharmacies. Data were derived from the Vancouver Injection Drug Users Study (VIDUS), a prospective cohort of PWID in Vancouver. Individuals were eligible to enrol in VIDUS if they had injected illicit drugs at least once in the previous month and lived in the Greater Vancouver region. Participants responded to an interviewer-administered questionnaire and provided blood samples at enrolment and follow-up visits every 6 months. We estimated time to HIV seroconversion with Kaplan-Meier methods and used Cox proportional hazards methods to assess associations between methadone use and time to seroconversion. 1639 HIV-negative individuals were recruited between May 1, 1996, and May 31, 2013. Of these individuals, 138 had HIV seroconversion during a median of 75·5 months (IQR 33·4-115·3) of follow-up. In multivariate Cox regression analyses, methadone maintenance therapy remained independently associated with a reduced hazard of HIV infection after adjustment for sociodemographic characteristics and drug use patterns (adjusted relative hazard 0·64, 95% CI 0·41-0·98). Methadone maintenance therapy for PWID made available through primary care physicians and community pharmacies can help to achieve public health goals such as reducing the spread of HIV. US National Institutes of Health, Canada Research Chair, Canadian Institutes of Health Research.

Injection drug users’ involvement in drug dealing in the downtown eastside of Vancouver: Social organization and systemic violence

BackgroundIllicit drug markets are a key component of the risk environment surrounding injection drug use. However, relatively few studies have explored how injection drug users’ (IDUs) involvement in drug dealing shapes their experiences of drug market-related harm. This exploratory qualitative study aims to understand IDUs’ dealing activities and roles, as well as the perceived benefits and risks related to participation in illicit drug markets, including experiences of drug market violence. MethodsTen IDUs with extensive involvement in drug dealing activities were recruited from the Vancouver Injection Drug User Study (VIDUS) and participated in semi-structured qualitative interviews, which elicited discussion of experiences dealing drugs, perceived benefits and hazards related to dealing, and understandings of drug market violence. ResultsParticipant's involvement in drug market activities included corporate sales, freelance or independent sales, and opportunistic sales termed “middling” as well as drug market-related hustles entailing selling bogus drugs and robbing dealers. Participants primarily dealt drugs to support their own illicit drug use, and we found that arrest and criminal justice involvement, hazards stemming from drug debts, and drug market-related violence were key risks related to dealing activities. ConclusionThe challenges of managing personal consumption while selling drugs exacerbates the hazards associated with drug dealing. Efforts to address drug dealing among IDUs should consider both drug dependency and the material conditions that propel drug users towards dealing activities. Interventions should explore the potential of combining enhanced drug treatment programs with low threshold employment and alternative income generation opportunities.

The role of depression and social support in non-fatal drug overdose among a cohort of injection drug users in a Canadian setting

ObjectivesNon-fatal overdose remains a significant source of morbidity among people who inject drugs (IDU). Although depression and social support are important in shaping the health of IDU, little is known about the relationship between these factors and overdose. Therefore, we sought to determine whether depressive symptoms and social support predicted non-fatal overdose among IDU in a Canadian setting. MethodsData were derived from three prospective cohorts of people who use drugs: the Vancouver Injection Drug Users Study (VIDUS), the ACCESS Cohort, and the At-Risk Youth Study (ARYS). Multilevel modeling was used to determine if depression and social support were significant predictors of non-fatal overdose across time. Analyses were stratified by sex. ResultsThere were 1931 participants included in this analysis, including 653 (33.8%) females and 69 (3.6%) youth 20 years old or younger. Depressed men (adjusted odds ratio [AOR]=1.53, 95% confidence intervals [CI]=1.25, 1.87) and women (adjusted odds ratio [AOR]=2.23, 95% confidence intervals [CI]=1.65, 3.00) were more likely to experience a non-fatal overdose. Further, among women, those who reported having 3 or more persons they could rely upon for social support were less likely to experience a non-fatal overdose (AOR=0.54, 95% CI 0.31, 0.93). ConclusionAlthough depression was a significant predictor of non-fatal drug overdose, social support was a significant predictor among women only. Possible strategies to prevent non-fatal overdose may include identifying IDU experiencing severe depressive symptoms and providing targeted mental health treatments and mobilizing interpersonal social support among IDU, especially among women.

Patterns of injection drug use cessation during an expansion of syringe exchange services in a Canadian setting

BackgroundNeedle and syringe programmes (NSPs) have been shown to reduce HIV risk among people who inject drugs (IDUs). However, concerns remain that NSPs delay injecting cessation. MethodsIndividuals reporting injection drug use in the past six months in the greater Vancouver area were enrolled in the Vancouver Injection Drug Users Study (VIDUS). Annual estimates of the proportion of IDU reporting injecting cessation were generated. Generalized estimating equation (GEE) analysis was used to assess factors associated with injecting cessation during a period of NSP expansion. ResultsBetween May 1996 and December 2010, the number of NSP sites in Vancouver increased from 1 to 29 (P<0.001). The estimated proportion of participants (n=2710) reporting cessation increased from 2.4% (95% confidence interval [CI]: 0.0–7.0%) in 1996 to 47.9% (95% CI: 46.8–48.9%) in 2010 (P<0.001). In a multivariate GEE analysis, the authors observed an association between increasing calendar year and increased likelihood of injecting cessation (Adjusted Odds Ratio=1.17, 95% CI: 1.15, 1.19, P<0.001). ConclusionThe proportion of IDU reporting injecting cessation increased during a period of NSP expansion, implying that increased NSP availability did not delay injection cessation. These results should help inform community decisions on whether to implement NSPs.

Difficulty accessing crack pipes and crack pipe sharing among people who use drugs in Vancouver, Canada

BackgroundCrack pipe sharing can increase health risks among people who use drugs, yet the reasons for sharing these pipes have not been well described. Therefore, we sought to identify the prevalence and correlates of crack pipe sharing among a community-recruited sample of people who use illicit drugs in Vancouver, a setting where crack pipes are provided at low or no cost.FindingsData for this study were derived from two prospective cohorts of people who use drugs: the Vancouver Injection Drug Users Study (VIDUS) and the AIDS Care Cohort to evaluate Exposure to Survival Services (ACCESS). Multivariate logistic regression was used to identify factors independently associated with crack pipe sharing. Among 503 crack users, 238 (47.3%) participants reported having shared a crack pipe in the previous six months. Having acquired a mouthpiece in the last six months (adjusted odds ratio [AOR] = 1.91; 95% confidence interval [CI]: 1.31 - 2.79) and difficulty finding new pipes (AOR = 2.19; 95%CI: 1.42 - 3.37) were positively associated with pipe sharing. Binge drug use (AOR = 1.39; 95%CI: 0.96 - 2.02) was marginally associated with sharing pipes.DiscussionThere was a high prevalence of crack pipe sharing in a setting where crack pipes are distributed at low or no cost. Difficulty accessing crack pipes was independently and positively associated with this behavior. These findings suggest that additional efforts are needed to discourage crack pipe sharing as well as increase access to crack pipes.

Injection methamphetamine use is associated with an increased risk of attempted suicide: A prospective cohort study

BackgroundMethamphetamine (MA) use is a growing public health concern in many settings around the world. While some physical and mental health effects associated with injection MA use have been well described, little is known about the relationship between injecting MA and suicidal behavior. We sought to determine whether MA injection was associated with an increased risk of attempting suicide among a prospective cohort of injection drug users (IDUs) in Vancouver, Canada. MethodsBetween 2001 and 2008, eligible participants enrolled in the Vancouver Injection Drug Users Study (VIDUS) completed semi-annual questionnaires that elicited information regarding sociodemographics, drug use patterns, and mental health problems including suicidal behavior. We used Cox proportional hazards models with time-dependent covariates to determine whether self-reported MA injection was an independent predictor of attempting suicide at subsequent time points. ResultsOf 1873 eligible participants, 149 (8.0%) reported a suicide attempt, resulting in an incidence density of 2.5 per 100 person-years. Participants who attempted suicide were more likely to be younger (median: 35 vs. 40, p<0.01), female (48.3% vs. 35.1%, p<0.01), and of Aboriginal ancestry (43.6% vs. 31.3%, p<0.01). In a Cox proportional hazards model, MA injection was associated with an 80% increase in the risk of attempting suicide (adjusted hazard ratio=1.80, 95% CI: 1.08–2.99, p=0.02). ConclusionsThese findings suggest that IDUs who inject MA should be monitored for suicidal behavior. Improved integration of mental health and suicide prevention interventions within harm reduction and drug treatment programs may be fruitful.

Social structural factors that shape assisted injecting practices among injection drug users in Vancouver, Canada: a qualitative study

BackgroundInjection drug users (IDU) commonly seek manual assistance with illicit drug injections, a practice known to be associated with various health-related harms. We investigated the social structural factors that shape risks related to assisted injection and the harms that may result.MethodsTwenty semi-structured qualitative interviews were conducted with IDU enrolled in the ACCESS or Vancouver Injection Drug Users Study (VIDUS) who reported requiring assistance injecting in the past six months. Audio-recorded interviews were transcribed verbatim and a thematic analysis was conducted.ResultsBarriers to self-injecting included a lack of knowledge of proper injecting technique, a loss of accessible veins, and drug withdrawal. The exchange of money or drugs for assistance with injecting was common. Harms experienced by IDU requiring assistance injecting included theft of the drug, missed injections, overdose, and risk of blood-borne disease transmission. Increased vulnerability to HIV/HCV infection within the context of intimate relationships was represented in participant narratives. IDU identified a lack of services available for those who require assistance injecting, with notable mention of restricted use of Vancouver's supervised injection facility.ConclusionsThis study documents numerous severe harms that arise from assisted injecting. Social structural factors that shape the risks related to assisted injection in the Vancouver context included intimate partner relations and social conventions requiring an exchange of goods for provision of injecting assistance. Health services for IDU who need help injecting should include targeted interventions, and supervised injection facilities should attempt to accommodate individuals who require assistance with injecting.

Addiction Treatment and Stable Housing among a Cohort of Injection Drug Users

BackgroundUnstable housing and homelessness is prevalent among injection drug users (IDU). We sought to examine whether accessing addiction treatment was associated with attaining stable housing in a prospective cohort of IDU in Vancouver, Canada.MethodsWe used data collected via the Vancouver Injection Drug User Study (VIDUS) between December 2005 and April 2010. Attaining stable housing was defined as two consecutive “stable housing” designations (i.e., living in an apartment or house) during the follow-up period. We assessed exposure to addiction treatment in the interview prior to the attainment of stable housing among participants who were homeless or living in single room occupancy (SRO) hotels at baseline. Bivariate and multivariate associations between the baseline and time-updated characteristics and attaining stable housing were examined using Cox proportional hazard regression models.Principal FindingsOf the 992 IDU eligible for this analysis, 495 (49.9%) reported being homeless, 497 (50.1%) resided in SRO hotels, and 380 (38.3%) were enrolled in addiction treatment at the baseline interview. Only 211 (21.3%) attained stable housing during the follow-up period and of this group, 69 (32.7%) had addiction treatment exposure prior to achieving stable housing. Addiction treatment was inversely associated with attaining stable housing in a multivariate model (adjusted hazard ratio [AHR] = 0.71; 95% CI: 0.52–0.96). Being in a partnered relationship was positively associated with the primary outcome (AHR = 1.39; 95% CI: 1.02–1.88). Receipt of income assistance (AHR = 0.65; 95% CI: 0.44–0.96), daily crack use (AHR = 0.69; 95% CI: 0.51–0.93) and daily heroin use (AHR = 0.63; 95% CI: 0.43–0.92) were negatively associated with attaining stable housing.ConclusionsExposure to addiction treatment in our study was negatively associated with attaining stable housing and may have represented a marker of instability among this sample of IDU. Efforts to stably house this vulnerable group may be occurring in contexts outside of addiction treatment.

Harmful Microinjecting Practices Among a Cohort of Injection Drug Users in Vancouver Canada

Objectives: We sought to identify factors associated with harmful microinjecting practices in a longitudinal cohort of IDU. Methods: Using data from the Vancouver Injection Drug Users Study (VIDUS) between January 2004 and December 2005, generalized estimating equations (GEE) logistic regression was performed to examine sociodemographic and behavioral factors associated with four harmful microinjecting practices (frequent rushed injecting, frequent syringe borrowing, frequently injecting with a used water capsule, frequently injecting alone). Results: In total, 620 participants were included in the present analysis. Our study included 251 (40.5%) women and 203 (32.7%) self-identified Aboriginal participants. The median age was 31.9 (interquartile range: 23.4–39.3). GEE analyses found that each harmful microinjecting practice was associated with a unique profile of sociodemographic and behavioral factors. Discussion: We observed high rates of harmful microinjecting practices among IDU. The present study describes the epidemiology of harmful microinjecting practices and points to the need for strategies that target higher risk individuals including the use of peer-driven programs and drug-specific approaches in an effort to promote safer injecting practices.

An external evaluation of a peer-run outreach-based syringe exchange in Vancouver, Canada

Objective Vancouver, Canada has been the site of an epidemic of human immunodeficiency virus (HIV) amongst injection drug users (IDU). In response, the Vancouver Area Network of Drug Users (VANDU) initiated a peer-run outreach-based syringe exchange programme (SEP) called the Alley Patrol. We conducted an external evaluation of this programme, using data obtained from the Vancouver Injection Drug Users Study (VIDUS). Methods Using generalised estimating equations (GEE) we examined the prevalence and correlates of use of the SEP amongst VIDUS participants followed from 1 December 2000 to 30 November 2003. Results Of 854 IDU, 233 (27.3%) participants reported use of the SEP during the study period. In multivariate GEE analyses, service use was positively associated with living in unstable housing (adjusted odds ratio [AOR] = 1.83, 95% confidence interval [CI]: 1.39–2.40), daily heroin injection (AOR = 1.31, 95% CI: 1.01–1.70), daily cocaine injection (AOR = 1.34, 95% CI: 1.03–1.73), injecting in public (AOR = 3.07, 95% CI: 2.32–4.06), and negatively associated with needle reuse (AOR = 0.65, 95% CI: 0.46–0.92). Conclusion The VANDU Alley Patrol SEP succeeded in reaching a group of IDU at heightened risk for adverse health outcomes. Importantly, access to this service was associated with lower levels of needle reuse. This form of peer-based SEP may extend the reach of HIV prevention programmes by contacting IDU traditionally underserved by conventional syringe exchange programmes.

Assisted injection in outdoor venues: an observational study of risks and implications for service delivery and harm reduction programming

BackgroundAssisted injection and public injection have both been associated with a variety of individual harms including an increased risk of HIV infection. As a means of informing local IDU-driven interventions that target or seek to address assisted injection, we examined the correlates of receiving assistance with injecting in outdoor settings among a cohort of persons who inject drugs (IDU).MethodsUsing data from the Vancouver Injection Drug Users Study (VIDUS), an observational cohort study of IDU, generalized estimating equations (GEE) were performed to examine socio-demographic and behavioural factors associated with reports of receiving assistance with injecting in outdoor settings.ResultsFrom January 2004 to December 2005, a total of 620 participants were eligible for the present analysis. Our study included 251 (40.5%) women and 203 (32.7%) self-identified Aboriginal participants. The proportion of participants who reported assisted injection outdoors ranged over time between 8% and 15%. Assisted injection outdoors was independently and positively associated with being female (Adjusted Odds Ratio (AOR) = 1.74, 95% Confidence Intervals (CI): 1.21-2.50), daily cocaine injection (AOR = 1.70, 95% CI: 1.29-2.24), and sex trade involvement (AOR = 1.44, 95% CI: 1.00-2.06) and was negatively associated with Aboriginal ethnicity (AOR = 0.58, 95% CI: 0.41-0.82).ConclusionsOur findings indicate that a substantial proportion of local IDU engage in assisted injecting in outdoor settings and that the practice is associated with other markers of drug-related harm, including being female, daily cocaine injecting and sex trade involvement. These findings suggest that novel interventions are needed to address the needs of this subpopulation of IDU.

Incarceration and drug use patterns among a cohort of injection drug users

Drug law enforcement remains the dominant response to drug-related harm. However, the impact of incarceration on deterring drug use remains under-evaluated. We sought to explore the relationship between incarceration and patterns of drug use among people who inject drugs (IDU). Using generalized estimating equations (GEE), we examined the prevalence and correlates of injection cessation among participants in the Vancouver Injection Drug User Study followed over 9 years. In subanalyses, we used McNemar's tests and linear growth curve analyses to assess changes in drug use patterns before and after a period of incarceration among participants reporting incarceration and those not incarcerated. Among 1603 IDU, 842 (53%) reported injection cessation for at least 6 months at some point during follow-up. In multivariate GEE analyses, recent incarceration was associated negatively with injection cessation [adjusted odds ratio (AOR) = 0.43, 95% confidence interval (CI) 0.37-0.50], whereas the use of methadone was associated positively with cessation (AOR = 1.38, 95% CI 1.22-1.56). In subanalyses assessing longitudinal patterns of drug use among incarcerated individuals and those not incarcerated over the study period, linear growth curve analyses indicated that there were no statistically significant differences in patterns of drug use between the two groups (all P > 0.05). These observational data suggest that incarceration does not reduce drug use among IDU. Incarceration may inhibit access to mechanisms that promote injection cessation among IDU. In contrast, results indicate that methadone use is associated positively with injection cessation, independent of previous frequency of drug use.

Public injecting among a cohort of injecting drug users in Vancouver, Canada

Despite the implementation of policy interventions to address open drug consumption, public injecting continues to occur in many urban settings. This study sought to examine public injecting among a community-recruited cohort of injecting drug users (IDUs) in Vancouver. The prevalence and correlates of recent public injecting among participants enrolled in the Vancouver Injection Drug User Study during the period of 1 December 2003 to 30 November 2005 were examined prospectively using generalised estimating equations (GEEs). Among the sample of 620 active IDUs, at some point during the study period, 142 (22.9%) individuals reported "usually" or "always" injecting in public in the 6 months prior to their study visit. Factors that were significant and positively associated with recent frequent public injecting in multivariate GEE analysis include homelessness (adjusted OR (AOR) 6.70); frequent crack use (AOR 1.48); and frequent heroin injection (AOR 1.56). Recent frequent public injecting was found to be negatively associated with cooking and filtering drugs prior to injecting (AOR 0.50) and older age (AOR 0.95). The findings indicate that a substantial proportion of local IDUs frequently inject in public, and those who report recently injecting in public spaces appear to be a vulnerable population facing significant health hazards. The provision of secure housing may have the potential to protect the health of IDUs in this setting and significantly decrease the prevalence of public injecting. In addition, the findings support previous work suggesting that removing barriers to the use of Vancouver's existing supervised injection site may serve to further reduce public drug use.