A socio-structural approach to preventing injection drug use initiation: rationale for the PRIMER study

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

INTRODUCTION

We sought to identify latent profiles of polysubstance use patterns among people who inject drugs in three distinct North American settings, and then determine whether profile membership was associated with providing injection initiation assistance to injection-naïve persons.

METHODS

Cross-sectional data from three linked cohorts in Vancouver, Canada; Tijuana, Mexico; and San Diego, USA were used to conduct separate latent profile analyses based on recent (i.e., past 6 months) injection and non-injection drug use frequency. We then assessed the association between polysubstance use patterns and recent injection initiation assistance provision using logistic regression analyses.

RESULTS

A 6-class model for Vancouver participants, a 4-class model for Tijuana participants and a 4-class model for San Diego participants were selected based on statistical indices of fit and interpretability. In all settings, at least one profile included high-frequency polysubstance use of crystal methamphetamine and heroin. In Vancouver, several profiles were associated with a greater likelihood of providing recent injection initiation assistance compared to the referent profile (low-frequency use of all drugs) in unadjusted and adjusted analyses, however, the inclusion of latent profile membership in the multivariable model did not significantly improve model fit.

DISCUSSION AND CONCLUSIONS

We identified commonalities and differences in polysubstance use patterns among people who inject drugs in three settings disproportionately impacted by injection drug use. Our results also suggest that other factors may be of greater priority when tailoring interventions to reduce the incidence of injection initiation. These findings can aid in efforts to identify and support specific higher-risk subpopulations of people who inject drugs.

First-line opioid agonist treatment as prevention against assisting others in initiating injection drug use: A longitudinal cohort study of people who inject drugs in Vancouver, Canada

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.

Transition from nonmedical prescribed opioids to non-injection heroin use among young integrated Thai male users in Bangkok

Opioid use and misuse are understudied in Thailand despite evidence suggesting that a portion of young Thai male integrated drug users are initiating use of non-medical prescribed opioids with some transitioning to heroin. This study aims to capture and analyze the individual and social factors influencing these transitions. Twenty in-depth semi-structured interviews were conducted between December 2019 and January 2020 in the Bangkok metropolitan area with young male opioid users who transitioned to heroin. Sixteen respondents initiated opioid through a Tramadol cocktail named "YaPro" and tended to transition to heroin use within 21 months. The interaction of specific social and individual factors such as joining recreational activities, curiosity or experimentation gradually modified the opioid-related meanings, attitude and practices of Thai users, who ultimately transition to heroin use. These results indicate that drug prevention programs in Thailand should encompass young opioid users in their intervention and further research need to focus on nonmedical use of prescription opioids in Thailand.

Promoting Healthy Attitudes and Behaviors in Youth Who Experience Homelessness: Results of a Longitudinal Intervention Study

PURPOSE

The aim of this study is to determine the effectiveness of a brief intervention to promote responsible substance use and safe sex behaviors in youths experiencing homelessness (YEH).

METHODS

Design: A Solomon four-group (double randomized controlled trial) longitudinal design with repeated measures (3- and 6-month follow-ups) was used in drop-in centers for YEH in Austin, Texas and Columbus, Ohio from which 602 youths, 18-24 years-old (M = 21 ± 1.8), 50% white; 69.9% heterosexual were recruited. A manualized one-on-one intervention consisted of six modules delivered via laptop computers. Modules focused on communication, goal-setting, substance use refusal, safe sex behaviors, enhanced psychological capital (hope, optimism, resilience, self-efficacy, gratitude), and life satisfaction. Valid and reliable measures of hope, optimism, future time perspective, resilience, social connectedness, gratitude, condom intention, self-efficacy for safe sex, safe sex behaviors, self-efficacy for substance use refusal, and life satisfaction were used to collect data for which three hypotheses were tested, using intent to treat, with multi-level modeling (R).

RESULTS

The analysis showed partial support for all hypotheses: (1) post-test outcomes were greater than pretests; (2) intervention group outcomes were greater than control group measures; and (3) significant effects for pretesting. YEH in Ohio completed significantly more sessions than YEH in Texas (p = .001), but took significantly longer to complete all six sessions (p = .001).

DISCUSSION

This brief intervention had significant effects on YEH to promote healthy attitudes and behaviors that merit further testing in larger samples.

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

BACKGROUND

Evidence suggests people who inject drugs (PWID) prescribed opioid agonist treatment (OAT) are less likely to provide injection drug use (IDU) initiation assistance. We investigated the association between OAT engagement and providing IDU initiation assistance across poly-drug use practices in Vancouver, Canada.

METHODS

Preventing Injecting by Modifying Existing Responses (PRIMER) is a prospective study seeking to identify structural interventions that reduce IDU initiation. We employed data from linked cohorts of PWID in Vancouver and extended the findings of a latent profile analysis (LPA). Multivariable logistic regression models were performed separately for the six poly-drug use LPA classes. The outcome was recently assisting others in IDU initiation; the independent variable was recent OAT engagement.

RESULTS

Among participants (n = 1218), 85 (7.0%) reported recently providing injection initiation assistance. When adjusting for age and sex, OAT engagement among those who reported a combination of high-frequency heroin and methamphetamine IDU and low-to-moderate-frequency prescription opioid IDU and methamphetamine non-injection drug use (NIDU) was associated with lower odds of IDU initiation assistance provision (Adjusted Odds Ratio [AOR]: 0.18, 95% CI: 0.05-0.63, P = 0.008). Significant associations were not detected among other LPA classes.

CONCLUSIONS

Our findings extend evidence suggesting that OAT may provide a population-level protective effect on the incidence of IDU initiation and suggest that this effect may be specific among PWID who engage in high-frequency methamphetamine and opioid use. Future research should seek to longitudinally investigate potential causal pathways explaining the association between OAT and initiation assistance provision among PWID to develop tailored intervention efforts.

Gender and the first-time provision of injection initiation assistance among people who inject drugs across two distinct North American contexts: Tijuana, Mexico and Vancouver, Canada

INTRODUCTION

Injection drug use initiation is commonly facilitated by other people who inject drugs (PWID). We investigated how the gender of PWID influences their risk of providing initiation assistance to others across two distinct geo-cultural settings.

METHODS

Data were drawn from two prospective cohorts in Tijuana, Mexico and Vancouver, Canada which conducted semi-annual interviews within the PReventing Injecting by Modifying Existing Responses (PRIMER) study. Participants consisted of PWID who had reported never providing injection initiation assistance at baseline. We then conducted site-specific discrete-time survival analyses assessing the relationship between gender and other relevant covariates (e.g. age and past 6-month sex work) on the risk of the first reported instance of providing initiation assistance.

RESULTS

Of 1988 PWID (Tijuana: n = 596; Vancouver: n = 1392), 256 (43%) and 511 (36.7%) participants were women, and 42 (1.7%) and 78 (1.6%) reported recent injection initiation assistance across a median of three and two follow-up visits, respectively. Women had a lower risk of providing injection initiation assistance for the first time in Tijuana (adjusted hazard ratio = 0.52, 95% confidence interval 0.27-0.99), but not in Vancouver. Gendered pathways, like sex work, were associated with providing initiation assistance for the first time in Vancouver (adjusted hazard ratio = 1.97, 95% confidence interval 1.08-3.61).

DISCUSSION AND CONCLUSIONS

Women in Tijuana, but not Vancouver, were less likely to provide first-time initiation assistance among PWID. These results can inform gender- and site-specific prevention efforts aimed at reducing transitions into drug injecting across geographic contexts.

"I would rather do it myself": injection initiation and current injection patterns among women who inject drugs in Tijuana, Mexico

BACKGROUND

Women who inject drugs (WWID) experience unique risks and adverse health outcomes related to injection initiation and patterns of injection drug use. However, there is limited information on injection initiation experiences and injection patterns among women and the protective strategies employed to limit injection-related harms, especially in low- and middle-income settings. Therefore, this study sought to explore injection initiation and current injection patterns (e.g., relying on someone else to inject) among women who inject drugs and engage in sex work in Tijuana, Mexico.

METHODS

Semistructured in-depth interviews were conducted with 30 WWID on the following topics: injection initiation, current injection patterns, places where women inject, and protective strategies (i.e., risk reduction). All interviews were audio-recorded, transcribed, and de-identified. An inductive thematic analysis was conducted to identify and compare common themes and patterns across participants.

RESULTS

The interviews revealed that the vast majority of study participants were first initiated by another person who injects drugs (PWID), often a male sexual partner. However, the majority of the women transitioned to become self-injectors in order to avoid risks associated with relying on others for injection, including overdose, interpersonal violence, sexual abuse, and wounds. Those who relied on others indicated that they would prefer to inject themselves without assistance from others if they were able to.

CONCLUSIONS

The narratives uncovered in this study reveal the importance of multiple risk environments in shaping perceived risks associated with injection drug use among women in Tijuana, Mexico. Specifically, the interviews elucidate the connection between interpersonal relationships with other PWID and protective strategies used to minimize risk and harm. These findings highlight the need for women-centered harm reduction programs to facilitate the development of safer drug use environments among WWID in Tijuana, Mexico.

Cost-effectiveness of hepatitis C virus (HCV) elimination strategies among people who inject drugs (PWID) in Tijuana, Mexico

BACKGROUND AND AIMS

In Latin America, Mexico was first to launch a hepatitis C virus (HCV) elimination strategy, where people who inject drugs (PWID) are a main risk group for transmission. In Tijuana, HCV seroprevalence among PWID is > 90%, with minimal harm reduction (HR). We evaluated cost-effectiveness of strategies to achieve the incidence elimination target among PWID in Tijuana.

METHODS

Modeling study using a dynamic, cost-effectiveness model of HCV transmission and progression among active and former PWID in Tijuana, to assess the cost-effectiveness of incidence elimination strategies from a health-care provider perspective. The model incorporated PWID transitions between HR stages (no HR, only opioid agonist therapy, only high coverage needle-syringe programs, both). Four strategies that could achieve the incidence target (80% reduction by 2030) were compared with the status quo (no intervention). The strategies incorporated the number of direct-acting anti-viral (DAA) treatments required with: (1) no HR scale-up, (2) HR scale-up from 2019 to 20% coverage among PWID, (3) HR to 40% coverage and (4) HR to 50% coverage. Costs (2019 US$) and health outcomes [disability-adjusted life years (DALYs)] were discounted 3% per year. Mean incremental cost-effectiveness ratios (ICER, $/DALY averted) were compared with one-time per capita gross domestic product (GDP) ($9698 in 2019) and purchasing power parity-adjusted per capita GDP ($4842-13 557) willingness-to-pay (WTP) thresholds.

RESULTS

DAAs alone were the least costly elimination strategy [$173 million, 95% confidence interval (CI) = 126-238 million], but accrued fewer health benefits compared with strategies with HR. DAAs + 50% HR coverage among PWID averted the most DALYs but cost $265 million, 95% CI = 210-335 million). The optimal strategy was DAAs + 50% HR (ICER $6743/DALY averted compared to DAAs only) under the one-time per-capita GDP WTP ($9698).

CONCLUSIONS

A combination of high-coverage harm reduction and hepatitis C virus treatment is the optimal cost-effective strategy to achieve the HCV incidence elimination goal in Mexico.

Involvement of people who inject drugs in injection initiation events: a cross-sectional analysis identifying similarities and differences across three North American settings

OBJECTIVES

People who inject drugs (PWID) play an integral role in facilitating the entry of others into injection drug use (IDU). We sought to assess factors influencing PWID in providing IDU initiation assistance across three distinct North American settings and to generate pooled measures of risk.

DESIGN

We employed data from three PWID cohort studies participating in PReventing Injecting by Modifying Existing Responses (PRIMER), for this cross-sectional analysis.

SETTING

Tijuana, Mexico; San Diego, USA; Vancouver, Canada.

PARTICIPANTS

A total of 2944 participants were included in this study (Tijuana: n=766, San Diego: n=353, Vancouver: n=1825).

MEASUREMENTS

The outcome was defined as recently (ie, past 6 months) assisting in an IDU initiation event. Independent variables of interest were identified from previous PRIMER analyses. Site-specific multiple modified Poisson regressions were fit. Pooled relative risks (pRR) were calculated and heterogeneity across sites was assessed via linear random effects models.

RESULTS

Evidence across all three sites indicated that having a history of providing IDU initiation assistance (pRR: 4.83, 95% CI: 3.49 to 6.66) and recently being stopped by law enforcement (pRR: 1.49, 95% CI: 1.07 to 2.07) were associated with a higher risk of providing assistance with IDU initiation; while recent opioid agonist treatment (OAT) enrolment (pRR: 0.64, 95% CI: 0.43 to 0.96) and no recent IDU (pRR: 0.21, 95% CI: 0.07 to 0.64) were associated with a lower risk. We identified substantial differences across site in the association of age (I²: 52%), recent housing insecurity (I²: 39%) and recent non-injection heroin use (I²: 78%).

CONCLUSION

We identified common and site-specific factors related to PWID's risk of assisting in IDU initiation events. Individuals reporting a history of assisting IDU initiations, being recently stopped by law enforcement, and recently injecting methamphetamine/speedball were more likely to have recently assisted an IDU initiation. Whereas those who reported not recently engaging in IDU and those recently enrolled in OAT were less likely to have done so. Interventions and harm reduction strategies aimed at reducing the harms of IDU should incorporate context-specific approaches to reduce the initiation of IDU.

Investigating a bidirectional relationship between overdose and provision of injection initiation assistance among persons who inject drugs in Vancouver, Canada and Tijuana, Mexico

BACKGROUND

Individuals who initiate injection drug use often receive assistance from an injection-knowledgeable peer. Persons who assist peers in injection initiation events often inject frequently, which heightens overdose risk. As such, overdose and injection initiation events may be correlated. To explore a potential relationship, we assessed temporal associations between experiencing a non-fatal overdose and assisting others in initiating injection drug use among persons who inject drugs in two North American cities - Vancouver, Canada and Tijuana, Mexico.

METHODS

From 2014 to 2018, this retrospective cohort study included people who inject drugs from Vancouver (n=1332) and Tijuana (n=666) who completed a baseline and six-month follow-up interview. Within each site, we assessed bidirectional temporal associations using two separate multivariable logistic regression models: for model 1, recent provision of injection initiation assistance (at six months) was the outcome and recent overdose (at baseline) was the exposure; for model 2, recent overdose (at six months) was the outcome and recent provision of injection initiation assistance (at baseline) was the exposure. Both models adjusted for potential confounders.

RESULTS

Vancouver-based participants reporting overdose at baseline had 163% greater odds of reporting provision of injection initiation assistance at follow-up (adjusted Odds Ratio [aOR] 2.63; 95% Confidence Interval [CI] 1.41-4.90); while participants reporting provision of injection initiation assistance at baseline had 89% greater odds of reporting a non-fatal overdose at follow-up (aOR 1.89; 95% CI 1.00-3.57). Among Tijuana-based participants, we did not observe a statistically significant association in either direction.

CONCLUSION

Findings in Vancouver suggest that injection initiation assistance and overdose are bidirectionally-associated phenomena. The present findings highlight the need for interventions that ensure that persons who provide injection initiation assistance are given overdose prevention support, both for themselves and for those they assist to initiate injection drug use. While our Tijuana-based results did not suggest a bidirectional relationship, preventative approaches should nonetheless be undertaken.

The impact of recent homelessness on the provision of injection drug use initiation assistance among persons who inject drugs in Tijuana, Mexico and Vancouver, Canada

OBJECTIVE

To assess the relationship between experiencing homelessness and assisting injection drug use (IDU) initiation among people who inject drugs (PWID) in Tijuana, Mexico and Vancouver, Canada.

METHODS

We used self-reported questionnaire data collected semi-annually on PWID from Tijuana (n = 703) and Vancouver (n = 1551) between 2014 and 2017. Within each setting, the effect of recent (i.e., past six months) homelessness on recent provision of injection initiation assistance (i.e., helping anybody inject for the first time in the past six months) was estimated using inverse-probability-of-treatment (IPT)-weighted estimation of a marginal structural model.

RESULTS

Across follow-up, the prevalence of recent homelessness at a given visit ranged from 11.6%-16.5% among Tijuana-based participants and 9.4%-18.9% among Vancouver-based participants; the prevalence of recent provision of injection initiation at a given follow-up visit was lower, ranging from 3.3%-5.4% in Tijuana and 2.5%-4.1% in Vancouver. Based on the IPT-weighted estimates, recent homelessness was associated with 66% greater odds among Tijuana-based PWID (Adjusted Odds Ratio [AOR] = 1.66; 95% CI: 1.01-2.73) and 47% greater odds among Vancouver-based PWID (AOR = 1.47, 95% CI: 1.02-2.13) of providing injection initiation assistance over the same six-month period.

CONCLUSION

We found that recently experiencing homelessness was associated with an increased likelihood of PWID reporting IDU initiation assistance over time in both Tijuana and Vancouver. Addressing homelessness may decrease the initiation of IDU via multiple pathways.

A Review of Recent HIV Prevention Interventions and Future Considerations for Nursing Science

ABSTRACT

As our knowledge of HIV evolved over the decades, so have the approaches taken to prevent its transmission. Public health scholars and practitioners have engaged in four key strategies for HIV prevention: behavioral-, technological-, biomedical-, and structural/community-level interventions. We reviewed recent literature in these areas to provide an overview of current advances in HIV prevention science in the United States. Building on classical approaches, current HIV prevention models leverage intimate partners, families, social media, emerging technologies, medication therapy, and policy modifications to effect change. Although much progress has been made, additional work is needed to achieve the national goal of ending the HIV epidemic by 2030. Nurses are in a prime position to advance HIV prevention science in partnership with transdisciplinary experts from other fields (e.g., psychology, informatics, and social work). Future considerations for nursing science include leveraging transdisciplinary collaborations and consider social and structural challenges for individual-level interventions.

Examining the gender composition of drug injecting initiation events: A mixed methods investigation of three North American contexts

BACKGROUND

Gender influences the health and social risks faced by individuals initiating drug injecting. Using mixed methods across three settings in North America, we investigated the gender composition of injection initiation events and the gendered risk environments in which they occurred.

METHODS

The PReventing Injecting by Modifying Existing Responses (PRIMER) study pooled data from three prospective community-recruited cohorts of people who inject drugs (PWID) in San Diego, USA, Vancouver, Canada, and Tijuana, Mexico. A qualitative subsample provided narrative data on their experiences of, and the contexts for, injection initiation events. Guided by Rhodes' risk environment framework, we examined the gender composition of initiation events stratified by city, and analyzed qualitative data using abductive thematic analyses.

RESULTS

Among 2,622 PWID (Tijuana: n = 531; San Diego: n = 352; Vancouver: n = 1,739), 112 (4.3%) reported providing initiation assistance to injection-naïve individuals in the previous six months. The proportion of gender concordant (e.g., male-male) initiation pairs varied, (χ2 = 10.32, p <0.001) with greater than expected concordance among pairs in Tijuana compared with those in Vancouver or San Diego. Sixty-one interviews provided context for the discrepancy across sites by highlighting the gendered injection initiation risk environments of prison/jail detention in Tijuana, intimate partnerships in San Diego, and overdose risk in Vancouver.

CONCLUSIONS

These results highlight how gender influences injection initiation events within spatial, social, and economic risk environments, and how this influence varies across settings. These findings can inform interventions to reduce the risk of injection initiation and related harms.

"I Know It Is Going to Ruin Their Life:" Fortune-Telling, Agency, and Harm Reduction in Narratives Concerning Injection Initiation Assistance

BACKGROUND

Considering most people who inject drugs (PWID) received help with the first injection, understanding the perspective of potential 'initiators' is a priority to inform harm reduction interventions. This paper examines how PWID narrate their experiences with injection initiation and assistance from the lens of their lived experience and perceptions of harm reduction.

METHODS

In-depth interviews were conducted with individuals who reported injection drug use and recent (past 30 days) opioid use in Baltimore (N = 19) and Anne Arundel County (N = 4), Maryland and analyzed using a narrative approach.

RESULTS

Respondents cast initiation events as meaningful transitions to a life characterized by predictable harms, including homelessness, infections, and social stigma. Respondents used examples from their personal experience to explain experiences with initiation and assistance by strategically attributing personal agency and predicting specific injection-related harms for initiates. In their narratives, respondents balanced notions of individual agency with harm reduction intentions by distinguishing between two forms of harm: perceived inevitable distal harm caused by long-term injection (e.g. socioeconomic decline) and potentially avoidable proximal harm caused by risky injection practices (e.g. overdose, HIV).

CONCLUSIONS

These findings highlight opportunities for interventions targeting injection initiation events and support the implementation of safer injection training in interventions. This identity of the 'responsible drug user' could be leveraged to support employing peers to help mitigate harm among inexperienced PWID either through peer outreach or formal venues, such as overdose prevention sites.

Peer Influence in Initiation to Heroin Use

Much research on heroin initiation shows that most people use heroin initially with friends or family. However, there is little research examining why those who use heroin would initiate others to its use, and conversely, whether and why one might try to prevent initial heroin use in others. Following recent work on peer influence on crime and delinquency, we test the hypothesis that those with higher levels of self-control are less likely to initiate others to heroin use and are more likely to try to prevent others from using for the first time. The sample included 370 persons entering an opioid withdrawal program. We find that those with low self-control are more likely to initiate others, but there is no relationship between self-control and trying to prevent initiation. We further investigate self-reported motives for initiating others, and find a mix of self-interested and more altruistic motives for initiating others.

The role of drug treatment and recovery services: an opportunity to address injection initiation assistance in Tijuana, Mexico

BACKGROUND

In the U.S. and Canada, people who inject drugs' (PWID) enrollment in medication-assisted treatment (MAT) has been associated with a reduced likelihood that they will assist others in injection initiation events. We aimed to qualitatively explore PWID's experiences with MAT and other drug treatment and related recovery services in Tijuana Mexico, a resource-limited setting disproportionately impacted by injection drug use.

METHODS

PReventing Injecting by Modifying Existing Responses (PRIMER) seeks to assess socio-structural factors associated with PWID provision of injection initiation assistance. This analysis drew on qualitative data from Proyecto El Cuete (ECIV), a Tijuana-based PRIMER-linked cohort study. In-depth qualitative interviews were conducted with a subset of study participants to further explore experiences with MAT and other drug treatment services. Qualitative thematic analyses examined experiences with these services, including MAT enrollment, and related experiences with injection initiation assistance provision.

RESULTS

At PRIMER baseline, 607(81.1%) out of 748 participants reported recent daily IDU, 41(5.5%) reported recent injection initiation assistance, 92(12.3%) reported any recent drug treatment or recovery service access, and 21(2.8%) reported recent MAT enrollment (i.e., methadone). Qualitative analysis (n = 21; female = 8) revealed that, overall, abstinence-based recovery services did not meet participants' recovery goals, with substance use-related social connections in these contexts potentially shaping injection initiation assistance. Themes also highlighted individual-level (i.e., ambivalence and MAT-related stigma) and structural-level (i.e., cost and availability) barriers to MAT enrollment.

CONCLUSION

Tijuana's abstinence-based drug treatment and recovery services were viewed as unable to meet participants' recovery-related goals, which could be limiting the potential benefits of these services. Drug treatment and recovery services, including MAT, need to be modified to improve accessibility and benefits, like preventing transitions into drug injecting, for PWID.

Prevalence and Correlates of Providing and Receiving Assistance With the Transition to Injection Drug Use

Preventing the transition to injection drug use is an important public health goal, as people who inject drugs (PWID) are at high risk for overdose and acquisition of infectious disease. Initiation into drug injection is primarily a social process, often involving PWID assistance. A better understanding of the epidemiology of this phenomenon would inform interventions to prevent injection initiation and to enhance safety when assistance is provided. We conducted a systematic review of the literature to 1) characterize the prevalence of receiving (among injection-naive persons) and providing (among PWID) help or guidance with the first drug injection and 2) identify correlates associated with these behaviors. Correlates were organized as substance use behaviors, health outcomes (e.g., human immunodeficiency virus infection), or factors describing an individual's social, economic, policy, or physical environment, defined by means of Rhodes' risk environments framework. After screening of 1,164 abstracts, 57 studies were included. The prevalence of receiving assistance with injection initiation (help or guidance at the first injection) ranged 74% to 100% (n = 13 estimates). The prevalence of ever providing assistance with injection initiation varied widely (range, 13%-69%; n = 13 estimates). Injecting norms, sex/gender, and other correlates classified within Rhodes' social risk environment were commonly associated with providing and receiving assistance. Nearly all PWID receive guidance about injecting for the first time, whereas fewer PWID report providing assistance. Substantial clinical and statistical heterogeneity between studies precluded meta-analysis, and thus local-level estimates may be necessary to guide the implementation of future psychosocial and sociostructural interventions. Further, estimates of providing assistance may be downwardly biased because of social desirability factors.

The role of gender and power dynamics in injection initiation events within intimate partnerships in the US-Mexico border region

Women's initiation into injection drug use often establishes a pattern of risk following first injection. This study explored sources of gendered power dynamics in injection initiation experiences for people who inject drugs. A qualitative subsample from two prospective community-recruited cohorts of people who inject drugs in San Diego and Tijuana provided data on the contexts surrounding injection initiation processes. Intimate partnerships were identified in initiation; sub-themes were identified drawing on three concepts within the theory of gender and power. With reference to sexual division of labour, men were often responsible for access to resources in partnerships across both contexts, although there were limited accounts of women obtaining those resources. Extending the structure of power, women in San Diego reported that initiation events involving an intimate partner occurred from a position of vulnerability but expressed greater agency when providing initiation assistance. With regard to structure of cathexis, social norms proscribing injection initiation among women exist, particularly in Tijuana. Gendered power dynamics are a multifaceted component of injection initiation events, especially for women in intimate partnerships. These results stress the need for nuance in understanding the intersection of risk, gender and harm reduction within injection initiation events across socio-cultural contexts.

Self-perception of assisting with future injection drug initiation: The influence of relationships in the process of drug injecting initiation

INTRODUCTION AND AIMS

People who inject drugs (PWID) play critical roles in assisting others into injection drug use (IDU) initiation. Understanding perceptions of PWID's risk of initiating others is needed to inform interventions for prevention. The objective was to examine factors associated with self-perception of assisting with future IDU initiation events. The primary variables of interest are the relationships of PWID with the person(s) they assisted and their reasons for previously providing initiation assistance.

DESIGN AND METHODS

Data from Preventing Injecting by Modifying Existing Responses, a multi-site prospective community-recruited cohort study, were analysed. Analyses were restricted to PWID who reported ever providing IDU initiation assistance. Site-specific (Vancouver, Canada [n = 746]; San Diego, USA [n = 95] and Tijuana, Mexico [n = 92]) multivariable logistic regression analyses were performed to determine factors associated with self-perception of assisting with future IDU initiation.

RESULTS

Having provided IDU initiation assistance to a family member or intimate partner decreased the odds of self-perception of assisting with future IDU initiation in Vancouver (AOR = 0.4; 95% CI 0.2-0.8); however, previous IDU initiation assistance to an 'other' increased the odds of self-perception of assisting with future IDU in Tijuana (AOR = 12.0; 95% CI 2.1-70.3). Daily IDU (Vancouver: AOR = 3.7; 95% CI 2.1-6.4) and less than daily IDU (San Diego: AOR = 5.9; 95% CI 1.3-27.1) (Vancouver: AOR = 2.6; 95% CI 1.4-2.9) were associated with increased self-perception of assisting with future IDU compared to current non-injectors.

DISCUSSION AND CONCLUSIONS

Relationship to past initiates and IDU frequency might increase PWID's self-perception of assisting with future IDU. Interventions focused on social support and reducing IDU frequency may decrease occurrences of IDU initiation assistance.

Preventing transitions into injection drug use: A call for gender-responsive upstream prevention

In 2017, there were large increases (260-500%) in overdose deaths among women in the United States across age groups (30-64 years and 55-64 years). In addition, U.S. women who inject drugs (WWID) are at increased risk for substance use-related disease transmission, bacterial infections, as well as sexual and physical violence compared to men who inject drugs. Relatedly, women face unique access barriers to substance use-related services, such as stigma and low coverage of gender-specific drug use-related services. Despite these heightened risks experienced by WWID, interventions specifically tailored to preventing women from transitioning into injection drug use have not been developed to date. As such, we advocate for the development of gender-responsive programs to prevent injection drug use initiation. This is critical to ensuring a comprehensive approach to preventing injection drug use initiation among those populations at highest risk of injection-related morbidity and mortality.

Recent incarceration and risk of first-time injection initiation assistance: A prospective cohort study of persons who inject drugs

BACKGROUND

Given the prevalence and harms of incarceration among persons who inject drugs (PWID) and their role in injection drug use initiation, we aimed to investigate whether recent incarceration influences the likelihood PWID assist others in their first-ever injection.

METHODS

Prospective cohort study of PWID in Vancouver, Canada who had their PReventing Injecting by Modifying Existing Responses (PRIMER) baseline visit between December 2014 and May 2017, reported never providing injection initiation assistance previously, and had ≥1 follow-up visit. The primary outcome, provision of injection initiation assistance, was defined via self-report as helping anybody inject for the first time in the past six months. The primary exposure was recent incarceration, i.e., self-report of being jailed, imprisoned or detained in the past six months. Participants were assessed biannually until November 2017, drop-out, or their first report of the primary outcome.

RESULTS

1,199 PWID (62.1% male; mean (SD) age, 44.4 (12.3) years) were included in our study. Across 4,171 follow-up visits, 67 participants (5.6%) reported providing injection initiation assistance. The proportion of participants reporting recent incarceration varied between 2.4% to 5.1% per follow-up visit. Based on a multivariable discrete-time proportional hazards regression analysis, recent incarceration was associated with an increased risk of providing injection initiation assistance during the same six-month period (adjusted hazard ratio, 2.64; 95% CI, 1.19 to 5.86).

CONCLUSIONS

The observed association between recent incarceration and risk of providing injection initiation assistance suggests that incarceration could be contributing to the expansion of injection drug use practices within vulnerable populations over time.

Reasons for assisting with injection initiation: Results from a large survey of people who inject drugs in Los Angeles and San Francisco, California

Injection drug initiation usually requires assistance by someone who already injects drugs. To develop interventions that prevent people from starting to inject drugs, it is imperative to understand why people who inject drugs (PWID) assist with injection initiation.

METHODS

Injection initiation history and motives for initiating others were collected from 978 PWID in Los Angeles and San Francisco, CA, from 2016-17. This article documents motivations for providing injection initiation assistance and examines demographic, economic, and health-related factors associated with these motivations using multivariable logistic regression modeling.

RESULTS

Among the 405 PWID who ever facilitated injection initiation, motivations for initiating were: injury prevention (66%), skilled at injecting others (65%), to avoid being pestered (41%), in exchange for drugs/money (45%), and for food/shelter/transportation (15%). High frequency initiation (>5 lifetime injection initiations) was associated with all motivations except for being pestered. Initiation to prevent injury was associated with being female. Initiation due to pestering was associated with recycling income and sex work. Being skilled was associated with age and HIV status, while initiation for money or drugs was associated with age, race, education, social security income, and substance use treatment. Lastly, initiation for food, shelter, or transportation was associated with age, sexual orientation and education level.

CONCLUSION

Diverse factors were associated with reported motivations for assisting someone to initiate injection for the first time. Our analysis underscores the need for prevention strategies focused on improving economic and housing conditions along with implementing drug consumption rooms to disrupt the social processes of injection initiation.

Evaluating networked drug checking services in Toronto, Ontario: study protocol and rationale

BACKGROUND

The increasing incidence of fatal opioid overdose is a public health crisis in Canada. Given growing consensus that this crisis is related to the presence of highly potent opioid adulterants (e.g., fentanyl) in the unregulated drug supply, drug checking services (DCS) have emerged as part of a comprehensive approach to overdose prevention. In Canada's largest city, Toronto, a network of DCS launched in 2019 to prevent overdose and overdose-related risk behaviors. This network employs mass spectrometry technologies, with intake sites co-located with supervised consumption services (SCS) at three frontline harm reduction agencies. The protocol and rationale for assessing the impact of this multi-site DCS network in Toronto is described herein. The aims of this study are to (1) evaluate the impact of DCS access on changes in and factors influencing overdose and related risk behaviors, (2) investigate the perceived capacity of DCS to prevent overdose, and (3) identify composition (qualitative and quantitative) trends in Toronto's unregulated drug supply.

METHODS

We will use a parallel-mixed-methods design with complementary data sources (including data from chemical analysis of drug samples, quantitative intake and post-test surveys, SCS, coroners, paramedic services, and qualitative interviews), followed by a meta-inference process wherein results from analyses are synthesized.

RESULTS

Whereas most DCS globally target "recreational drug users," in Toronto, this networked DCS will primarily target marginalized people who use drugs accessing frontline services, many of whom use drugs regularly and by injection. This evolution in the application of DCS poses important questions that have not yet been explored, including optimal service delivery models and technologies, as well as unique barriers for this population. Increasing information on the unregulated drug supply may modify the risk environment for this population of people who use drugs.

CONCLUSIONS

This study addresses evidence gaps on the emerging continuum of overdose prevention responses and will generate critical evidence on a novel approach to reducing the ongoing high incidence of drug-related morbidity and mortality in Canada and elsewhere.

Application of data mining techniques and logistic regression to model drug use transition to injection: a case study in drug use treatment centers in Kermanshah Province, Iran

BACKGROUND

Drug injection has been increasing over the past decades all over the world. Hepatitis B and C viruses (HBV and HCV) are two common infections among people who inject drugs (PWID) and more than 60% of new human immunodeficiency virus (HIV) cases are PWID. Thus, investigating risk factors associated with drug use transition to injection is essential and was the aim of this research.

METHODS

We used a database from drug use treatment centers in Kermanshah Province (Iran) in 2013 that included 2098 records of people who use drugs (PWUD). The information of 29 potential risk factors that are commonly used in the literature on drug use was selected. We employed four classification methods (decision tree, neural network, support vector machine, and logistic regression) to determine factors affecting the decision of PWUD to transition to injection.

RESULTS

The average specificity of all models was over 84%. Support vector machine produced the highest specificity (0.9). Also, this model showed the highest total accuracy (0.91), sensitivity (0.94), positive likelihood ratio [1] and Kappa (0.94) and the smallest negative likelihood ratio (0). Therefore, important factors according to the support vector machine model were used for further interpretation.

CONCLUSIONS

Based on the support vector machine model, the use of heroin, cocaine, and hallucinogens were identified as the three most important factors associated with drug use transition injection. The results further indicated that PWUD with the history of prison or using drug due to curiosity and unemployment are at higher risks. Unemployment and unreliable sources of income were other suggested factors of transition in this research.

Opioid agonist treatment scale-up and the initiation of injection drug use: A dynamic modeling analysis

BACKGROUND

Injection drug use (IDU) is associated with multiple health harms. The vast majority of IDU initiation events (in which injection-naïve persons first adopt IDU) are assisted by a person who injects drugs (PWID), and as such, IDU could be considered as a dynamic behavioral transmission process. Data suggest that opioid agonist treatment (OAT) enrollment is associated with a reduced likelihood of assisting with IDU initiation. We assessed the association between recent OAT enrollment and assisting IDU initiation across several North American settings and used dynamic modeling to project the potential population-level impact of OAT scale-up within the PWID population on IDU initiation.

METHODS AND FINDINGS

We employed data from a prospective multicohort study of PWID in 3 settings (Vancouver, Canada [n = 1,737]; San Diego, United States [n = 346]; and Tijuana, Mexico [n = 532]) from 2014 to 2017. Site-specific modified Poisson regression models were constructed to assess the association between recent (past 6 month) OAT enrollment and history of ever having assisted an IDU initiation with recently assisting IDU initiation. Findings were then pooled using linear mixed-effects techniques. A dynamic transmission model of IDU among the general population was developed, stratified by known factors associated with assisting IDU initiation and relevant drug use behaviors. The model was parameterized to a generic North American setting (approximately 1% PWID) and used to estimate the impact of increasing OAT coverage among PWID from baseline (approximately 21%) to 40%, 50%, and 60% on annual IDU initiation incidence and corresponding PWID population size across a decade. From Vancouver, San Diego, and Tijuana, respectively, 4.5%, 5.2%, and 4.3% of participants reported recently assisting an IDU initiation, and 49.4%, 19.7%, and 2.1% reported recent enrollment in OAT. Recent OAT enrollment was significantly associated with a 45% lower likelihood of providing recent IDU initiation assistance among PWID (relative risk [RR] 0.55 [95% CI 0.36-0.84], p = 0.006) compared to those not recently on OAT. Our dynamic model predicts a baseline mean of 1,067 (2.5%-97.5% interval [95% I 490-2,082]) annual IDU initiations per 1,000,000 individuals, of which 886 (95% I 406-1,750) are assisted by PWID. Based on our observed statistical associations, our dynamic model predicts that increasing OAT coverage from approximately 21% to 40%, 50%, or 60% among PWID could reduce annual IDU initiations by 11.5% (95% I 2.4-21.7), 17.3% (95% I 5.6-29.4), and 22.8% (95% I 8.1-36.8) and reduce the PWID population size by 5.4% (95% I 0.1-12.0), 8.2% (95% I 2.2-16.9), and 10.9% (95% I 3.2-21.8) relative to baseline, respectively, in a decade. Less impact occurs when the protective effect of OAT is diminished, when a greater proportion of IDU initiations are unassisted by PWID, and when average IDU career length is longer. The study's main limitations are uncertainty in the causal pathway between OAT enrollment and assisting with IDU initiation and the use of a simplified model of IDU initiation.

CONCLUSIONS

In addition to its known benefits on preventing HIV, hepatitis C virus (HCV), and overdose among PWID, our modeling suggests that OAT scale-up may also reduce the number of IDU initiations and PWID population size.

Opioid Misuse Among HIV-Positive Adults in Medical Care: Results From the Medical Monitoring Project, 2009-2014

BACKGROUND

People living with HIV are prescribed opioids more often and at higher doses than people who do not have HIV, and disproportionately experience risk factors for substance use disorder, which suggests they could be at increased risk of the misuse of opioids. Researchers also suggest that opioid misuse negatively affects various HIV clinical outcomes, increasing the risk of transmission to partners with an HIV-negative status.

METHODS

We calculated weighted percentages and 95% confidence intervals to estimate substance use characteristics among a probability sample of 28,162 HIV-positive adults receiving medical care in the United States who misused opioids (n = 975). Then, we used Rao-Scott χ tests to assess bivariate associations between opioid misuse and selected characteristics.

RESULTS

In all, 3.3% misused opioids. Misuse was more common among young adults, males, and non-Hispanic whites. Persons who misused opioids were less likely to: have been prescribed antiretroviral therapy (ART) (88.7%), report being adherent to ART medications in the past 3 days (78.1%), and have durable viral suppression (54.3%) than persons who did not misuse opioids (92.5%, 87.7%, and 64.7%, respectively). Persons who misused opioids were more likely to report condomless sex with partners of negative or unknown HIV status while not durably virally suppressed (11.7% vs 3.4%) than persons who did not misuse opioids.

CONCLUSIONS

Opioid misuse among adults receiving HIV medical care is associated with inadequate ART adherence, insufficient durable viral suppression, and higher risk of HIV transmission to sexual partners.

Identification of a Syndemic of Blood-Borne Disease Transmission and Injection Drug Use Initiation at the US-Mexico Border

BACKGROUND

Efforts to prevent injection drug use (IDU) are increasingly focused on the role that people who inject drugs (PWID) play in the assistance with injection initiation. We studied the association between recent (ie, past 6 months) injection-related HIV risk behaviors and injection initiation assistance into IDU among PWID in the US-Mexico border region.

SETTING

Preventing Injecting by Modifying Existing Responses (PRIMER) is a multicohort study assessing social and structural factors related to injection initiation assistance. This analysis included data collected since 2014 from 2 participating cohorts in San Diego and Tijuana.

METHODS

Participants were 18 years and older and reported IDU within the month before study enrollment. Logistic regression analyses were conducted to assess the association between recent injection-related HIV risk behaviors (eg, distributive/receptive syringe sharing, dividing drugs in a syringe, and paraphernalia sharing) and recent injection initiation assistance.

RESULTS

Among 892 participants, 41 (4.6%) reported recently providing injection initiation assistance. In multivariable analysis adjusting for potential confounders, reporting a higher number of injection-related risk behaviors was associated with an increased odds of recently assisting others with injection initiation (adjusted odds ratio per risk behavior: 1.3; 95% confidence interval: 1.0 to 1.6, P = 0.04).

CONCLUSIONS

PWID who recently engaged in one or more injection-related HIV risk behavior were more likely to assist others in injection initiation. These results stress the syndemic of injection initiation and risk behaviors, which indicates that prevention of injection-related HIV risk behaviors might also reduce the incidence of injection initiation.

CAM Practices and Treatment Adherence Among Key Subpopulations of HIV+ Latinos Receiving Care in the San Diego-Tijuana Border Region: A Latent Class Analysis

Latinos living in the United States-Mexico border region bear a disproportionate HIV/AIDS burden compared to individuals living in the interior of both nations and face a constellation of barriers that determine their ability to access and adhere to HIV care. Use of complementary and alternative medicine (CAM) may be associated with suboptimal treatment adherence. Sociodemographic factors, health practices, and social determinants of health unique to the border region may further contribute to health disparities that undermine care engagement and continuity. Improved understanding of HIV-positive Latino subgroups and their risk profiles can lead to more effective, targeted clinical and public health interventions. We undertook this study to identify and characterize distinct classes of HIV-positive Latinos in the San Diego-Tijuana border region, differentiated by HIV and border-related factors, utilizing latent class analysis. We investigated relationships between class membership and CAM utilization and self-reported antiretroviral therapy (ART) adherence. Five distinct classes were identified with unique demographic, HIV risk, and border mobility profiles. CAM was recently used by nearly half of each class, though there were significant differences in the proportion of CAM use by class ranging from 44.4 to 90.9%. As well, all classes were currently receiving ART at similarly high rates and ART adherence outcomes were not significantly different based on class. Findings highlight the significant use of CAM by all HIV-positive Latinos in the border region and imply the need for a research framework which appropriately acknowledges the heterogeneous nature of this population, such as intersectionality. Further research is recommended into understanding how patients integrate CAM into HIV treatment and the risks and benefits of incorporating CAM into HIV treatment.

Factors Associated with Frequency of Recent Initiation of Others into Injection Drug Use Among People Who Inject Drugs in Los Angeles and San Francisco, CA, USA, 2016-17

Objective: Drug injection initiation is often assisted by a person who injects drugs (PWID). How often PWID provide this assistance has not been examined. We examine frequency of injection initiation assistance and factors associated with high (4+) and low frequency (1-3) initiation assistance as compared to no initiation assistance among PWID. Methods: Participants were 979 Californian PWID. PWID were interviewed about providing injection initiation assistance in the last 6 months among other items. Multinomial regression analysis was used to examine factors associated with levels of frequency of injection initiation assistance. Results: Among participants, 132 (14%) had initiated 784 people into injection (mean = 5.94 [standard deviation = 20.13]; median = 2, interquartile range = 1,4) in the last 6 months. PWID engaged in high frequency initiation (26% of sample) assisted 662 new initiates (84% of total). Using multinomial regression analysis with no initiating as the referent group, we found that high frequency initiating was statistically associated with higher injection frequency, having a paying sex partner, taking someone to a shooting gallery, and providing injection assistance. Lower frequency initiation was statistically associated with having a paying sex partner, illegal income source, and providing injection assistance. Conclusion: Differences between high and low frequency initiators were not found. Sex work and assisting with drug injection were linked to initiating others. Individual-level interventions that reduce this behavior among PWID and structural interventions such as safe consumption sites and opioid medication treatments that interrupt the social process of injection initiation should be considered as ways to reduce injection initiations.

Navigating social norms of injection initiation assistance during an overdose crisis: A qualitative study of the perspectives of people who inject drugs (PWID) in Vancouver, Canada

Despite the proliferation of fentanyl and fentanyl-adulterated opioids in North America, the impacts of this drug market change on injection initiation processes have not been examined. With the aim of informing structural interventions to address injection initiation and related harms, we explore how people who inject drugs (PWID) in Vancouver, Canada understand and navigate social norms of initiating others into injecting within the context of an overdose crisis. In-depth qualitative interviews were conducted with 19 PWID who reported helping someone inject for the first time. Participants were recruited from two cohort studies of PWID. Participants articulated moral dilemmas about assisting others with injecting. While participants described a 'moral code' prohibiting assisting injection-naïve individuals, this code was not the sole consideration shaping social action around injection initiation. Rather, PWID exercised agency about whether and how to assist novice injectors within the context of constraining and enabling social norms around practicing interpersonal responsibility. Changes to the drug market heightened feelings of moral culpability and criminal liability among PWID who assisted others into injection, given that injecting heightened initiates' risk of overdose. These concerns operated in tension with the aim of protecting novice injectors from harms associated with an increasingly potent and unpredictable drug supply by providing them with injection assistance, education and supervision. Our analysis of how PWID practice interpersonal responsibility helps conceptualise how 'moral codes' prohibiting initiation assistance are managed and negotiated amidst structural vulnerability. Structural interventions reducing the vulnerability of novice injectors should be prioritized, including the implementation of supervised injection sites allowing for assisted injection, Good Samaritan laws, and policy changes conducive to a safer drug supply.

Opioid agonist treatment and the process of injection drug use initiation

BACKGROUND

Opioid agonist treatment (OAT) is an effective biomedical intervention to manage opioid use disorder among persons who inject drugs (PWID). Preliminary evidence suggests that OAT may also disrupt the social communicability of injection drug use (IDU) practices by established PWID. We therefore aim to investigate the association between OAT enrollment and initiating others into IDU among PWID in Vancouver, Canada.

METHODS

Preventing Injecting by Modifying Existing Responses (PRIMER; NIDA DP2-DA040256-01) is a prospective multi-cohort study seeking to identify structural interventions that reduce the risk that PWID initiate others into IDU. The present analysis was conducted using data from a participating cohort of PWID in Vancouver, Canada, between December 2014 and May 2017. Multivariable logistic regression models were built to assess the association between reporting active (i.e., within the past six months) OAT enrollment and assisting others in injection initiation. A final model was determined using a manual stepwise approach whereby covariates were excluded if their removal altered the coefficient of interest by <5%.

RESULTS

Participants (n = 1740) were predominantly male (62.3%); 35.1% reported daily injecting (n = 611); 860 (49.4%) reported active OAT enrollment, and 80 (4.6%) reported recently providing injection initiation assistance. In a multivariable model, participants who reported active OAT enrollment had significantly lower odds of recently providing injection initiation assistance (Adjusted Odds Ratio = 0.52, 95% Confidence Interval: 0.31-0.87, P = 0.01).

CONCLUSION

Results suggest a protective association between OAT and the expansion of IDU practices among vulnerable populations, suggesting its potential use as 'addiction treatment as prevention.'

Impact of drug consumption rooms on risk practices and access to care in people who inject drugs in France: the COSINUS prospective cohort study protocol

INTRODUCTION

The high prevalence of hepatitis C and the persistence of HIV and hepatitis C virus (HCV) risk practices in people who inject drugs (PWID) in France underlines the need for innovative prevention interventions. The main objective of this article is to describe the design of the COSINUS cohort study and outline the issues it will explore to evaluate the impact of drug consumption rooms (DCR) on PWID outcomes. Secondary objectives are to assess how DCR (a) influence other drug-related practices, such as the transition from intravenous to less risky modes of use, (b) reduce drug use frequency/quantity, (c) increase access to treatment for addiction and comorbidities (infectious, psychiatric and other), (d) improve social conditions and (e) reduce levels of violence experienced and drug-related offences. COSINUS will also give us the opportunity to investigate the impact of other harm reduction tools in France and their combined effect with DCR on reducing HIV-HCV risk practices. Furthermore, we will be better able to identify PWID needs.

METHODS AND ANALYSIS

Enrollment in this prospective multi-site cohort study started in June 2016. Overall, 680 PWID in four different cities (Bordeaux, Marseilles, Paris and Strasbourg) will be enrolled and followed up for 12 months through face-to-face structured interviews administered by trained staff to all eligible participants at baseline (M0), 3 month (M3), 6 month (M6) and 12 month (M12) follow-up visits. These interviews gather data on socio-demographic characteristics, past and current drug and alcohol consumption, drug-use related practices, access to care and social services, experience of violence (as victims), offences, other psychosocial issues and perception and needs about harm reduction interventions and services. Longitudinal data analysis will use a mixed logistic model to assess the impact of individual and structural factors, including DCR attendance and exposure to other harm reduction services, on the main outcome (HIV-HCV risk practices).

ETHICS AND DISSEMINATION

This study was reviewed and approved by the institutional review board of the French Institute of Medical Research and Health (opinion number: 14-166). The findings of this cohort study will help to assess the impact of DCR on HIV-HCV risk practices and other psycho-social outcomes and trajectories. Moreover, they will enable health authorities to shape health and harm reduction policies according to PWID needs. Finally, they will also help to improve current harm reduction and therapeutic interventions and to create novel ones.

Age of Initiation and Patterns of Use among People Who Inject Drugs Welcomed in Harm Reduction Facilities in France from 2006 to 2015

This exploratory analysis of time-series cross-sectional data provides insights on trends in age at first injection among people who inject drugs in France, and on associations with recent risky injecting behaviors. Data were collected from a national survey conducted in harm reduction facilities in five phases between 2006 and 2015. Standardized questionnaires collected information on demographics, substance use, and route of administration, as well as lifetime and past-month injection. Descriptive and multilevel models were applied to account for the hierarchical structure of the data. Prevalence of lifetime and past-month injection remained stable over time, while the prevalence of daily injection increased significantly. Mean age at first injection only appeared to increase for data collected after 2010. Gender differences in mean age at first injection decreased over time, suggesting the development of converging patterns of initiation independent of sex. After controlling for covariates, early initiation of injection was unrelated to daily injection or material sharing, and associated with the number of recently injected substances. Early initiation is likely a predictor of injected polysubstance use. Findings are relevant to the planning, implementation, and evaluation of prevention programs.

"Another Person Was Going to Do It": The Provision of Injection Drug Use Initiation Assistance in a High-Risk U.S.-Mexico Border Region

Background: Persons who inject drugs (PWID) play a key role in assisting others' initiation into injection drug use (IDU). We aimed to explore the pathways and socio-structural contexts for this phenomenon in Tijuana, Mexico, a border setting marked by a large PWID population with limited access to health and social services. Methods: Preventing Injecting by Modifying Existing Responses (PRIMER) is a multi-cohort study assessing socio-structural factors associated with PWID assisting others into initiating IDU. Semi-structured qualitative interviews in Tijuana included participants ≥18 years old, who reported IDU within the month prior to cohort enrollment and ever initiating others into IDU. Purposive sampling ensured a range of drug use experiences and behaviors related to injection initiation assistance. Thematic analysis was used to develop recurring and significant data categories. Results: Twenty-one participants were interviewed (8 women, 13 men). Broadly, participants considered public injection to increase curiosity about IDU. Many considered transitioning into IDU as inevitable. Emergent themes included providing assistance to mitigate overdose risk and to protect initiates from being taken advantage of by others. Participants described reluctance in engaging in this process. For some, access to resources (e.g., shared drugs or a monetary fee) was a motivator to initiate others. Conclusion: In Tijuana, public injection and a lack of harm reduction services are perceived to fuel the incidence of IDU initiation and to incentivize PWID to assist in injection initiation. IDU prevention efforts should address structural factors driving PWID participation in IDU initiation while including PWID in their development and implementation.

Where Is the Opioid Use Epidemic in Mexico? A Cautionary Tale for Policymakers South of the US-Mexico Border

In North America, opioid use and its harms have increased in the United States and Canada over the past 2 decades. However, Mexico has yet to document patterns suggesting a higher level of opioid use or attendant harms.Historically, Mexico has been a country with low-level use of opioids, although heroin use has been documented. Low-level opioid use is likely attributable to structural, cultural, and individual factors. However, a range of dynamic factors may be converging to increase the use of opioids: legislative changes to opioid prescribing, national health insurance coverage of opioids, pressure from the pharmaceutical industry, changing demographics and disease burden, forced migration and its trauma, and an increase in the production and trafficking of heroin. In addition, harm-reduction services are scarce.Mexico may transition from a country of low opioid use to high opioid use but has the opportunity to respond effectively through a combination of targeted public health surveillance of high-risk groups, preparation of appropriate infrastructure to support evidence-based treatment, and interventions and policies to avoid a widespread opioid use epidemic.

Gender differences in the provision of injection initiation assistance: a comparison of three North American settings

AIM

Individuals experience differential risks in their initiation into drug injecting based on their gender. Data suggest women are more likely to be injected after their initiator and to share injection equipment. Little is known, however, regarding how gender influences the risk that people who inject drugs (PWID) may assist others into injection initiation. We therefore sought to investigate the role of "initiator" gender in the provision of injection initiation assistance across multiple settings.

METHODS

We employed data from PReventing Injecting by Modifying Existing Responses (PRIMER), a multi-cohort study investigating factors influencing injection initiation assistance provision. Data were drawn from three cohort studies of PWID in San Diego, USA (STAHR II); Tijuana, Mexico (El Cuete IV); and Vancouver, Canada (VDUS). Site-specific logistic regression models were fit, with lifetime provision of injection initiation assistance as the outcome and gender as the independent variable.

RESULTS

Overall, 3.2% (24/746) of the women and 4.6% (63/1367) of the men reported providing injection initiation assistance. In Tijuana, men were more than twice as likely to have provided injection initiation assistance after controlling for potential confounders (adjusted odds ratio = 2.17, 95% confidence interval: 1.22-3.84). Gender was not significantly associated with providing injection initiation assistance in other sites.

CONCLUSION

We identified that being male in Tijuana, specifically, was associated with providing injection initiation assistance, which could inform targeted outreach aimed at reducing the influence of PWID populations on non-injectors in this site. This will likely require that existing interventions address gender- and site-specific factors for effectiveness.

Injection Drug Use Trajectories among Migrant Populations: A Narrative Review

BACKGROUND

Dual epidemics of injection drug use and blood-borne disease, characterized as "syndemics," are present in a range of settings. Behaviors that drive such syndemics are particularly prevalent among mobile drug-using populations, for whom cross-border migration may pose additional risks.

OBJECTIVES

This narrative review aims to characterize the risk factors for injection drug use initiation associated with migration, employing a risk environment framework and focusing on the San Diego-Tijuana border region as the most dynamic example of these phenomena.

METHODS

Based on previous literature, we divide migration streams into three classes: intra-urban, internal, and international. We synthesized existing literature on migration and drug use to characterize how mobility and migration drive the initiation of injection drug use, as well as the transmission of hepatitis and HIV, and to delineate how these might be addressed through public health intervention.

RESULTS

Population mixing between migrants and receiving communities and the consequent transmission of social norms about injection drug use create risk environments for injection drug use initiation. These risk environments have been characterized as a result of local policy environments, injection drug use norms in receiving communities, migration-related stressors, social dislocation, and infringement on the rights of undocumented migrants.

CONCLUSION

Policies that exacerbate risk environments for migrants may inadvertently contribute to the expansion of epidemics of injection-driven blood-borne disease. Successful interventions that address emerging syndemics in border regions may therefore need to be tailored to migrant populations and distinguish between the vulnerabilities experienced by different migration classes and border settings.

Frequency and factors associated with providing injection initiation assistance in Tallinn, Estonia

Injection drug use is expanding in numerous regions in the world. Persons who inject drugs (PWID) play an important role encouraging new persons into injecting, by providing injection initiation assistance ("assisting" behaviors) and stimulating interest in injection ("promoting" behaviors).

OBJECTIVES

To describe the prevalence of assisting and promoting behaviors, and to identify factors associated with assisting, among PWID in Tallinn, Estonia.

METHODS

In 2016, PWID were recruited through respondent-driven sampling (RDS), interviewed, and HIV tested. RDS weights were used to estimate the prevalence of assisting and promoting behaviors and, in multivariable regression modeling, to identify factors associated with assisting.

RESULTS

Among 299 PWID recruited, 13.7% had ever assisted a non-PWID with their first injection. Regarding past-six-month promoting behaviors: 9.4% talked positively about injecting to non-PWID, 16.2% injected in front of non-PWID, and 0.6% offered to help with a first injection. Significant predictors of ever assisting with a first injection included: gender (men: aOR 6.31, 95% CI 2.02-19.74); age (30 years or younger: aOR 3.89, 95% CI 1.40-10.16); receptive sharing of syringes or needles (aOR 4.73, 95% CI 1.32-16.98); ever testing for HIV (aOR 8.44, 95% CI 1.15-62.07); and having peers who helped someone with their first injection (aOR 3.44, 95% CI 1.31-9.03).

CONCLUSION

Demographic and drug-use related factors are associated with having initiated someone into injecting. Interventions targeting PWID and non-PWID are needed to prevent injection initiation.

A fragmented code: The moral and structural context for providing assistance with injection drug use initiation in San Diego, USA

BACKGROUND

Injection drug use initiation is shaped by social networks and structural contexts, with people who inject drugs often assisting in this process. We sought to explore the norms and contexts linked to assisting others to initiate injection drug use in San Diego, USA, to inform the development of structural interventions to prevent this phenomenon.

METHODS

We undertook qualitative interviews with a purposive sample of people who inject drugs and had reported assisting others to initiate injection (n = 17) and a sub-sample of people who inject drugs (n = 4) who had not reported initiating others to triangulate accounts. We analyzed data thematically and abductively.

RESULTS

Respondents' accounts of providing initiation assistance were consistent with themes and motives reported in other contexts: of seeking to reduce harm to the 'initiate', responding to requests for help, fostering pleasure, accessing resources, and claims that initiation assistance was unintentional. We developed analysis of these themes to explore initiation assistance as governed by a 'moral code'. We delineate a fragmented moral code which includes a range of meanings and social contexts that shape initiation assistance. We also show how assistance is happening within a structural context that limits discussion of injection drug use, reflecting a prevailing silence on drug use linked to stigma and criminalization.

CONCLUSIONS

In San Diego, the assistance of others to initiate injection drug use is governed by a fragmented moral code situated within particular social norms and contexts. Interventions that address the social and structural conditions shaped by and shaping this code may be beneficial, in tandem with efforts to support safe injection and the reduction of injection-related harms.

Cross-border migration and initiation of others into drug injecting in Tijuana, Mexico

INTRODUCTION AND AIMS

Efforts to prevent injection drug use (IDU) are increasingly focusing on the role that people who inject drugs (PWID) play in facilitating the entry of others into this behaviour. This is particularly relevant in settings experiencing high levels of IDU, such as Mexico's northern border region, where cross-border migration, particularly through forced deportation, has been found to increase a range of health and social harms related to injecting.

DESIGN AND METHODS

PWID enrolled in a prospective cohort study in Tijuana, Mexico, since 2011 were interviewed semi-annually, which solicited responses on their experiences initiating others into injecting. Univariate and multivariable logistic regression analyses were conducted at the Preventing Injection by Modifying Existing Responses (PRIMER) baseline, with the dependent variable defined as reporting ever initiating others into injection. The primary independent variable was lifetime deportation from the USA to Mexico.

RESULTS

Among 532 participants, 14% (n = 76) reported initiating others into injecting, the majority of participants reporting initiating acquaintances (74%, n = 56). In multivariable analyses, initiating others into injecting was independently associated with reporting living in the USA for 1-5 years [adjusted odds ratio (AOR) = 2.42; 95% confidence interval (CI) 1.22-4.79, P = 0.01], and methamphetamine and heroin injection combined (AOR = 3.67; 95% CI 1.11-12.17, P = 0.03). Deportation was not independently associated with initiating others into injecting.

DISCUSSION AND CONCLUSIONS

The impact of migration needs to be considered within binational programming seeking to prevent the expansion of epidemics of injecting and HIV transmission among mobile populations residing in the Mexico-USA border region.

Non-injection Drug Use and Injection Initiation Assistance among People Who Inject Drugs in Tijuana, Mexico

Although most people who inject drugs (PWID) report receiving assistance during injection initiation events, little research has focused on risk factors among PWID for providing injection initiation assistance. We therefore sought to determine the influence of non-injection drug use among PWID on their risk to initiate others. We used generalized estimating equation (GEE) models on longitudinal data among a prospective cohort of PWID in Tijuana, Mexico (Proyecto El Cuete IV), while controlling for potential confounders. At baseline, 534 participants provided data on injection initiation assistance. Overall, 14% reported ever initiating others, with 4% reporting this behavior recently (i.e., in the past 6 months). In a multivariable GEE model, recent non-injection drug use was independently associated with providing injection initiation assistance (adjusted odds ratio [AOR] = 2.42, 95% confidence interval [CI] = 1.39-4.20). Further, in subanalyses examining specific drug types, recent non-injection use of cocaine (AOR = 9.31, 95% CI = 3.98-21.78), heroin (AOR = 4.00, 95% CI = 1.88-8.54), and methamphetamine (AOR = 2.03, 95% CI = 1.16-3.55) were all significantly associated with reporting providing injection initiation assistance. Our findings may have important implications for the development of interventional approaches to reduce injection initiation and related harms. Further research is needed to validate findings and inform future approaches to preventing entry into drug injecting.

Do law enforcement interactions reduce the initiation of injection drug use? An investigation in three North American settings

BACKGROUND

The prevention of drug injecting is often cited as a justification for the deployment of law enforcement and for the continuation of drug criminalization policies. We sought to characterize the impact of law enforcement interactions on the risk that people who inject drugs (PWID) report assisting others with injection initiation in three North American countries.

METHODS

Cross-sectional data from PWID participating in cohort studies in three cities (San Diego, USA; Tijuana, Mexico; Vancouver, Canada) were pooled (August 2014-December 2016). The dependent variable was defined as recently (i.e., past six months) providing injection initiation assistance; the primary independent variable was the frequency of recent law enforcement interactions, defined categorically (0 vs. 1 vs. 2-5 vs. ≥6). We employed multivariable logistic regression analyses to assess this relationship while controlling for potential confounders.

RESULTS

Among 2122 participants, 87 (4.1%) reported recently providing injection initiation assistance, and 802 (37.8%) reported recent law enforcement interactions. Reporting either one or more than five recent interactions with law enforcement was not significantly associated with injection initiation assistance. Reporting 2-5 law enforcement interactions was associated with initiation assistance (Adjusted Odds Ratio=1.74, 95% Confidence Interval: 1.01-3.02).

CONCLUSIONS

Reporting interactions with law enforcement was not associated with a reduced likelihood that PWID reported initiating others into injection drug use. Instead, we identified a positive association between reporting law enforcement interactions and injection initiation assistance among PWID in multiple settings. These findings raise concerns regarding the effectiveness of drug law enforcement to deter injection drug use initiation.

The experience of initiating injection drug use and its social context: a qualitative systematic review and thematic synthesis

BACKGROUND AND AIM

Understanding the experience of initiating injection drug use and its social contexts is crucial to inform efforts to prevent transitions into this mode of drug consumption and support harm reduction. We reviewed and synthesized existing qualitative scientific literature systematically to identify the socio-structural contexts for, and experiences of, the initiation of injection drug use.

METHODS

We searched six databases (Medline, Embase, PsychINFO, CINAHL, IBSS and SSCI) systematically, along with a manual search, including key journals and subject experts. Peer-reviewed studies were included if they qualitatively explored experiences of or socio-structural contexts for injection drug use initiation. A thematic synthesis approach was used to identify descriptive and analytical themes throughout studies.

RESULTS

From 1731 initial results, 41 studies reporting data from 1996 participants were included. We developed eight descriptive themes and two analytical (higher-order) themes. The first analytical theme focused on injecting initiation resulting from a social process enabled and constrained by socio-structural factors: social networks and individual interactions, socialization into drug-using identities and choices enabled and constrained by social context all combine to produce processes of injection initiation. The second analytical theme addressed pathways that explore varying meanings attached to injection initiation and how they link to social context: seeking pleasure, responses to increasing tolerance to drugs, securing belonging and identity and coping with pain and trauma.

CONCLUSIONS

Qualitative research shows that injection drug use initiation has varying and distinct meanings for individuals involved and is a dynamic process shaped by social and structural factors. Interventions should therefore respond to the socio-structural influences on injecting drug use initiation by seeking to modify the contexts for initiation, rather than solely prioritizing the reduction of individual harms through behavior change.

History of medication-assisted treatment and its association with initiating others into injection drug use in San Diego, CA

BACKGROUND

Medication-assisted treatment (MAT) remains the gold standard for the treatment of opioid use disorder. MAT also reduces the frequency of injecting among people who inject drugs (PWID). Relatedly, data suggest that PWID play a key role in the initiation of others into drug injecting by exposing injecting practices to injection-naïve drug users. Our primary objective was to test whether a history of MAT enrollment is associated with a reduced odds of PWID providing injection initiation assistance.

METHODS

Preventing Injecting by Modifying Existing Responses (PRIMER; NIDA DP2-DA040256-01), is a multi-site cohort study assessing the impact of socio-structural factors on the risk that PWID provide injection initiation assistance. Data were drawn from a participating cohort of PWID in San Diego, CA. The primary outcome was reporting ever providing injection initiation assistance; the primary predictor was reporting ever being enrolled in MAT. Logistic regression was used to model associations between MAT enrollment and ever initiating others into injecting while adjusting for potential confounders.

RESULTS

Participants (n = 354) were predominantly male (n = 249, 70%). Thirty-eight percent (n = 135) of participants reported ever initiating others into injection drug use. In multivariate analysis, participants who reported a history of MAT enrollment had significantly decreased odds of ever providing injection initiation assistance (Adjusted Odds Ratio [AOR]: 0.62, 95% Confidence Interval [CI]: 0.39-0.99).

CONCLUSIONS

These preliminary findings suggest an association between MAT enrollment and a lower odds that male PWID report providing injection initiation assistance to injection-naïve drug users. Further research is needed to identify the pathways by which MAT enrollment may impact the risk that PWID initiate others into drug injecting.

The North American opioid epidemic: current challenges and a call for treatment as prevention

There is a need for creative, public health-oriented solutions to the increasingly intractable problems associated with the North American opioid epidemic. This epidemic is a fundamentally continental problem, as routes of migration, drug demand, and drug exchange link the USA with Mexico and Canada. The challenges faced throughout North America include entrenched prescribing practices of opioid medications, high costs and low availability of medication-assisted treatment (MAT), and policy approaches that present substantial barriers to care.We advocate for the scale up of a low-threshold treatment model for MAT that incorporates the best practices in addiction treatment. Such a model would remove barriers to care through widespread treatment availability and affordability and also a policy of decriminalization. Given that MAT reduces the frequency of drug injecting among opioid injectors, this treatment model should also be guided by an understanding of the socially communicable nature of injection drug use, such that increasing MAT availability may also prevent the spread of injecting practices to individuals at risk of transitions from non-injection to injection drug use. To that end, the "Treatment as Prevention" model employed to respond to the individual- and population-level risks for HIV/AIDS prevention could be adapted to efforts to halt the North American opioid epidemic.

Down in the valley: Trajectories of injection initiation among young injectors in California's Central Valley

BACKGROUND

Injection drug use initiation represents a critical point of public health intervention, as injection increases risk for blood borne infections including Hepatitis C and HIV. In this paper, we explore pathways to injection initiation among youth (≤30) in the rural context of California's Central Valley, where rates of injection drug use are among the highest in the nation.

METHODS

We draw on semi-structured qualitative interviews with 20 young injectors to examine drug use histories, including the factors that participants associated with their transition to injection drug use.

RESULTS

The average age was 24.7 years (range: 20-30), 45% were female (n=9), and 30% were Latino (n=6). Participants described a variety of pathways to injection, culminating in a first injection that involved either opioids (n=12) or methamphetamine (n=8). Among the opioid group, the majority used prescription opioids before transitioning to injection, while a smaller number transitioned to opioid injection from non-opioid recreational drug use. Injectors who first used prescription opioids often described growing up in affluent suburban areas and transitioned to injection with peers, owing to a combination of factors related to individual tolerance, cost, and shifting drug markets. In contrast, methamphetamine initiates grew up in less affluent families with histories of substance use that exposed them to drugs at an early age. Methamphetamine users transitioned from smoking and snorting to injection, often with family members or intimate partners, within broader contexts of social disadvantage and stress.

CONCLUSION

While much of the focus on young injectors has centred on the current opioid epidemic, our data suggest a need to consider multiple pathways towards injection initiation of different drugs. Targeted interventions addressing the unique injection transition contexts of both opioids and methamphetamine are urgently needed in the Central Valley of California.