Factors associated with being asked to initiate someone into injection drug use

The influence of transformations in supply on methamphetamine initiation among people injecting opioids in the United States

BACKGROUND

Co-use of methamphetamine (MA) and opioids (pharmaceutical pills, heroin and fentanyls) has increased in the United States and is represented in rising mortality. Although coinciding with the import of low cost, high potency and purity methamphetamine, the relationship between supply and demand in propelling this polydrug use is not well understood. We consider the influence of macro changes in supply on the uptake of opioid and methamphetamine co-use by injection at the level of individual drug and injection initiation in West Virginia, a state which leads the US in drug overdose mortality.

METHOD

We recruited n = 30 people for semi-structured interviews who self-reported injecting heroin/fentanyl and using methamphetamine by any route at a West Virginia syringe service program and through snowball sampling. Interviews were recorded and transcripts analyzed using a thematic approach. Ethnographic observation was also conducted and recorded in fieldnotes. Sequence of substance and mode of use initiation and use trajectories for opioids and stimulants were charted for each participant.

RESULTS

A clear pattern of individual drug initiation emerged that matched each successive supply wave of the US overdose epidemic: 25 participants had initiated opioid use with pills, followed by heroin, often mixed with/replaced by fentanyl, and subsequently added methamphetamine use. For participants, the supply and consumption of opioid analgesics had set in motion a series of steps leading to the addition of stimulant injection to existing opioid injecting repertoires. Unlike other studies that have found a birth cohort effect in patterns of initiation, participants showed the same sequence across age groups. Considerations of economy, availability, dependence, tolerance and the erosion of taboos that marked transitions from opioid pills to heroin injection influenced these subsequent trajectories in novel ways. The form, timing and extent of opioid and stimulant consumption was influenced by four stages of the changing drug supply, which in turn reflected back on demand.

CONCLUSION

Transformations in the social meaning and supply of methamphetamine enabled these transitions while other desired, non-injectable drugs were difficult to obtain. We discuss policy implications of injectable drugs' market dominance at this location and possible interventions.

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.

The practice and embodiment of "goofballs": A qualitative study exploring the co-injection of methamphetamines and opioids

BACKGROUND

Polysubstance use is common among people who use drugs, including the co-use of stimulants and opioids. Research suggests the practice of simultaneous co-injection of methamphetamines and opioids, often referred to as "goofballs", is increasing. As a relatively unique drug use practice, little qualitative research currently exists on goofball injecting. This study explores the practice and embodied experiences of goofball injecting.

METHODS

This article draws on in-depth interviews conducted across two qualitative studies undertaken in Vancouver, Canada's Downtown Eastside neighbourhood examining changing dynamics in relation to stimulant use and experiences with an overdose prevention site-based safer supply intervention, respectively. Interviews containing discussions of goofball use (n=29) were extracted from each study and merged into a single qualitative dataset. Data were analysed thematically and focused on the practices and embodied experiences of goofball injection.

RESULTS

Our analysis uncovered how goofball injection represented a complex drug use practice driven by the desire to achieve particular embodied experiences not attainable by using either drug individually. We identified three distinct practices of goofball use: 1) to alter or enhance the effects of opioids; 2) to alter or enhance the effects of methamphetamines; and 3) to balance out the effects of both drugs.

CONCLUSION

Our study fills an important gap in the polysubstance use literature specifically exploring the co-injection of methamphetamines and opioids. Our findings highlight the need to implement and expand interventions and services attentive to polysubstance use and the role of pleasure in drug taking practices, including expanding non-medicalized opioid and stimulant safer supply initiatives across North America.

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.

Injecting drug use opportunities and reasons for choosing not to inject: A population-based study of Australian young adults who use stimulants

INTRODUCTION

Understanding reasons for choosing not to inject drugs, among those who have never injected before, may be helpful for reducing transitions to injecting drug use. This study examines opportunities to inject and reasons for never injecting in young adults who used stimulants.

METHODS

Data are from a population-based study of young adults who used ecstasy and methamphetamine (n = 313), recruited in Queensland, Australia in 2008/2009. At the follow-up, participants who had never injected (n = 293) completed a 13-item instrument on reasons for never injecting. We conducted a principal components analysis to identify types of reasons (scored 0-100) and multivariate regression to predict endorsement of these reasons.

RESULTS

Approximately one-in-five of all participants ever had an opportunity to inject and there was no gender difference in the propensity to accept an opportunity. Four types of reasons, labelled risk perception, subjective effects, social environment and aversion, were identified. Male gender was associated with lower endorsement of risk perception (β = -7.94; 95% confidence interval [CI] -13.37, -2.51) and social environment (β = -7.35; 95% CI -13.15, -1.54). Having friends who injected was associated with lower endorsement of the social environment (β = -8.88; 95% CI -14.83, -2.94), and higher endorsement of aversion (β = 7.67; 95% CI 1.44, 13.89).

DISCUSSION AND CONCLUSIONS

Our findings suggest that injecting drug use opportunities are common among young adults engaged in recreational drug use, with males and females equally likely to accept an opportunity. A strong aversion to injecting and a hedonic preference for non-injecting drug use may reduce the likelihood of accepting these opportunities.

Patterns of and Rationale for the Co-use of Methamphetamine and Opioids: Findings From Qualitative Interviews in New Mexico and Nevada

INTRODUCTION

Methamphetamine use and methamphetamine-involved deaths have increased dramatically since 2015, and opioid-related deaths now frequently involve methamphetamine. Nevada and New Mexico are states with elevated rates of opioid and methamphetamine use. In this paper, we report results from a qualitative analysis that examined patterns of methamphetamine and opioid co-use over participants' lifespan, factors that influence those patterns, and implications for health outcomes among users.

METHODS

Project AMPED was a multisite, mixed-methods study of methamphetamine use in Northern New Mexico and Northern Nevada. Between December 2019 and May 2020, qualitative interview participants were asked to describe their patterns of and reasons for co-administration of opioids and methamphetamine.

RESULTS

We interviewed 21 people who reported using methamphetamine in the past 3 months. Four primary patterns of methamphetamine and opioid co-use were identified: [1] using both methamphetamine and heroin, either simultaneously or sequentially (n = 12), [2] using methamphetamine along with methadone (n = 4), [3] using prescription opioids and methamphetamine (n = 1), and [4] using only methamphetamine (n = 4). Among those who used methamphetamine and heroin simultaneously or sequentially, motivations drew from a desire to enhance the effect of one drug or another, to feel the "up and down" of the "perfect ratio" of a goofball, or to mitigate unwanted effects of one or the other. Among those who used methamphetamine and methadone, motivations focused on alleviating the sedative effects of methadone.

CONCLUSION

To address the emergent trend of increasing methamphetamine-related deaths, researchers, health care professionals, and community health workers must acknowledge the decision-making processes behind co-use of opioids and methamphetamine, including the perceived benefits and harms of co-use. There is an urgent need to address underlying issues associated with drug use-related harms, and to design interventions and models of treatment that holistically address participants' concerns.

Factors Associated with Likelihood of Initiating Others into Injection Drug Use Among People Who Inject Drugs in West Virginia

People who inject drugs (PWID) play a critical role in injection-naïve individuals transitioning to injection drug use. We investigated factors associated with future likelihood of initiating injection-naïve individuals using multivariable logistic regression among 418 PWID in rural Appalachia (Cabell County, West Virginia). Less than 10% reported they were likely to initiate someone in the future. Acquiring syringes from a syringe services program was associated with decreased odds of being likely to initiate someone in the future (adjusted odds ratio [aOR] 0.46, 95% CI 0.23, 0.95), while having previously initiated someone into injection drug use was associated with increased odds (aOR 8.65, 95% CI 4.07, 18.41). Among our sample of PWID in Appalachia, a small proportion reported that they would be likely to initiate an injection-naïve individual in the future. Efforts to reduce injection initiation assistance should focus on this subpopulation of PWID who indicate a willingness to engage in this behavior.

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.

Assisted injection provider practices and motivations in Los Angeles and San Francisco California 2016-18

BACKGROUND

Assisted injection is a high-risk and common practice among people who inject drugs (PWID) and occurs for diverse reasons according to qualitative research. To develop interventions for reducing assisted injection risks, it is important to understand the practices of PWID who provide injection assistance, including their motivations for providing assistance.

METHODS

Using follow-up data from an efficacy trial among PWID recruited in Los Angeles and San Francisco, CA (n=601), we present descriptive statistics on motivations for providing injection assistance and use multivariable logistic regression modelling to examine factors associated with these motivations.

RESULTS

PWID provided injection assistance most commonly to friends and acquaintances. A quarter provided assistance on a daily basis. The most common motivations for providing assistance were skill and injury prevention. PWID also provided assistance to stop pestering and for compensation in money or drugs. In separate models examining factors associated with the five main motivations, we found injury prevention to be associated with skill injecting others, neck injection, methamphetamine use, and recycling income. Pestering was associated with injury prevention, neck and hand injection, speedball use, and syringe selling. Skill was associated with injury prevention, neck and hand injection, being physically assaulted, and age. Providing assistance for money was associated with providing assistance for food or drugs, armpit injections, being female, and providing assistance more frequently. Providing assistance for drugs was associated with compensation in food or money, goofball injection, selling drugs, and panhandling.

CONCLUSION

Providing injection assistance is associated with injection needs of recipients and drug scene participation. We urgently need new interventions for reducing assisted injection risks. Since injection providers report being motivated by skill and to prevent injury, interventions such as training in safer injection techniques are likely to be met with enthusiasm.

Drug injection and associated factors among the elderly living with HIV/AIDS in Tehran, Iran

Background: Injection of drugs is one of the most serious health problems among Iranian living with HIV/AIDS. The injection of drugs, accounting for the transmission of more than two-thirds of HIV infections. HIV remains a major concern around the world and is expected to be the third leading cause of mortality worldwide. Thus, the aim of this study was to explore the predictors of injection drug use in the elderly patients living with HIV/AIDS. Methods: This was a cross-sectional study executed in Tehran City, Iran, in 2018. A total of 160 individuals aged 60 years and older with HIV from different counseling centers were selected by convenience sampling. Data were collected using questionnaires including a positive state of mind, coping, social support, and a checklist of demographical variables. Bivariate analysis and multiple logistic regression using SPSS software version 21.0 were employed to determine factors associated with drug injection. The statistical tests were performed with a significance level of 5% (p≥0.05). Results: The study participants' mean(SD) age was 65.6(±6.6) years. In total, 33 people (20.6%) of the samples reported injection drug use. The frequency of injection drug use was greater among men (AOR: 2.28, 95% CI 2.2-22.8; p=0.010), those reporting a monthly income of ≥30000000 Rials (AOR: 31.56, 95% CI 2.95-338; p=0.004), subjects with past experience of drug use (AOR: 7.11, 95% CI 2.18-23.2; p=0.001), those with ≥2 years past from their HIV diagnosis (AOR: 4.04, 95% CI 1.12-14.58; p=0.033), and those living with more than two people in one residential place (Household size AOR: 5.9, 95% CI 1.64-21.24; p=0.007). Conclusion: It seems that the design and implementation of harm reduction programs among the elderly with HIV/AIDS who inject drugs are essential and should be considered as an agenda of policymakers and health professionals.

"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.

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.

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.

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.

Cost-effectiveness of scaling-up HCV prevention and treatment in the United States for people who inject drugs

AIMS

To examine the cost-effectiveness of hepatitis C virus (HCV) treatment of people who inject drugs (PWID), combined with medication-assisted treatment (MAT) and syringe-service programs (SSP), to tackle the increasing HCV epidemic in the United States.

DESIGN

HCV transmission and disease progression models with cost-effectiveness analysis using a health-care perspective.

SETTING

Rural Perry County, KY (PC) and urban San Francisco, CA (SF), USA. Compared with PC, SF has a greater proportion of PWID with access to MAT or SSP. HCV treatment of PWID is negligible in both settings.

PARTICIPANTS

PWID data were collected between 1998 and 2015 from Social Networks Among Appalachian People, U Find Out, Urban Health Study and National HIV Behavioral Surveillance System studies.

INTERVENTIONS AND COMPARATOR

Three intervention scenarios modeled: baseline-existing SSP and MAT coverage with HCV screening and treatment with direct-acting antiviral for ex-injectors only as per standard of care; intervention 1-scale-up of SSP and MAT without changes to treatment; and intervention 2-scale-up as intervention 1 combined with HCV screening and treatment for current PWID.

MEASUREMENTS

Incremental cost-effectiveness ratios (ICERs) and uncertainty using cost-effectiveness acceptability curves. Benefits were measured in quality-adjusted life-years (QALYs).

FINDINGS

For both settings, intervention 2 is preferred to intervention 1 and the appropriate comparator for intervention 2 is the baseline scenario. Relative to baseline, for PC intervention 2 averts 1852 more HCV infections, increases QALYS by 3095, costs $21.6 million more and has an ICER of $6975/QALY. For SF, intervention 2 averts 36 473 more HCV infections, increases QALYs by 7893, costs $872 million more and has an ICER of $11 044/QALY. The cost-effectiveness of intervention 2 was robust to several sensitivity analysis.

CONCLUSIONS

Hepatitis C screening and treatment for people who inject drugs, combined with medication-assisted treatment and syringe-service programs, is a cost-effective strategy for reducing hepatitis C burden in the United States.

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.

Initiating Persons into Injection Drug Use in Rural West Virginia, USA

Background: While prior research has explored factors associated with people who inject drugs (PWID) initiating others into drug injection in urban settings, very little work has been done to understand this behavior among rural PWID in Appalachia. Objectives: We aim to identify factors associated with PWID initiating injection-naïve individuals into drug injection in a rural community in West Virginia (WV). Methods: Data were derived from a cross-sectional survey of 420 rural PWID (163 women) in Cabell County, WV in June-July 2018 who indicated recent (past 6 months) injection drug use. Individuals completed a survey that included measures on socio-demographics and injection socialization behaviors. We used logistic regression to identify factors associated with PWID recently initiating someone for their first injection. Results: A minority (17%) reported recently initiating someone for their first injection. In multivariable regression, recent injection initiation was independently associated with number of injections per day (adjusted odds ratio [aOR] 1.16; 95% confidence interval [CI]:1.07,1.25), recent injection in front of an injection-naïve person (aOR 2.75; 95% CI: 1.25,6.04), recent describing how to inject drugs to an injection-naïve person (aOR 5.83; 95% CI: 2.71,12.57), and recent encouragement of an injection-naïve person to inject (aOR 7.13; 95% CI: 2.31,21.87). Conclusion: Injection initiation was independently associated with several injection socialization behaviors involving injection-naïve individuals. PWID who recently initiated injection-naïve individuals had higher odds of frequent injection. Educating rural PWID about how their behaviors can influence others and the importance of engaging in safe injection practices could carry significant public health utility.

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.

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.'

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.

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.

Differences in time to injection onset by drug in California: Implications for the emerging heroin epidemic

BACKGROUND

Heroin use is increasing in the US. Heroin use may predispose users towards injection routes of drug administration as compared to other illicit substances.

OBJECTIVE

To explore the relationship between heroin use and drug injection, we compared time from first use to first injection (referred to as time to injection onset by drug [TTIOD]) of heroin, methamphetamine/speed, cocaine, and crack cocaine among people who inject drugs (PWID).

METHODS

Age of first use and first injection by drug was collected from 776 PWID. Survival analyses were used to determine TTIOD and to examine demographic factors associated with TTIOD. Cox regression analysis was used to determine demographic factors associated with drug-specific injection onset.

RESULTS

The eventual injection onset rate by the drug was 99% for participants who used heroin, 85% for participants who used methamphetamine/speed, 80% for participants who used powder cocaine, and 38% for participants who used crack cocaine. Hazard ratios for injection use within one year of first use by drug were: 1.37 (median survival time [MST] = 0.61 years) for heroin, 0.66 (MST = 1.10 years) for methamphetamine/speed, 0.50 (MST = 2.93 years) for powder cocaine, and 0.12 (MST = 39.59 years) for crack cocaine. Demographic differences in TTIOD were found for each drug. Demographic differences were found for eventual injection by drug for all substances except heroin.

CONCLUSION

Among PWID, heroin use was associated with a more rapid transition to injection and a higher rate of eventual heroin injection regardless of demographics. More robust, innovative efforts to reduce heroin use and prevent injection initiation are urgently needed.

Transition from First Drug Use to Regular Injection among People Who Inject Drugs in Iran

BACKGROUND

The study aimed to evaluate the interval between first drug use and regular injection and factors associated with transition from first injection into premature regular injection among people who inject drugs (PWIDs).

METHODS

In a multicenter cross-sectional study, we recruited 400 PWIDs using snowball sampling. Age of first drug use, age of initiation of regular injection, and demographic and behavioral data were collected using face to face interview. Premature transition to regular injection was defined as initiation of regular injection within the five years of first injection. Data were analyzed using bivariate and multivariate logistic regression survey analysis.

FINDINGS

The mean age of first drug use and age of initiation of regular injection was 29.87 ± 6.54 years, respectively. Having history of sexual abuse in childhood [adjusted odds ratio (AOR) = 3.1], history of imprisonment (AOR = 3.4), use of heroin as the first drug (AOR = 4.3), and doing the first injection at friends' houses (AOR = 2.2) or in ruins (AOR = 2.2) significantly increased the chance of premature transition to regular injection, while being a female decreased the chance of premature transition to regular injection (AOR = 0.4). Compared to curiosity, being friend with a drug user (AOR = 0.4), having withdrawal symptoms (AOR = 0.2), and low cost of injection (AOR = 0.3) at the first occasion of drug injection reduced the chance of premature transition to regular injection.

CONCLUSION

New interventions to prevent injection initiation among drug users are needed and should be integrated in harm reduction programs.

Heroin and Methamphetamine Injection: An Emerging Drug Use Pattern

OBJECTIVE

We sought to describe an emerging drug use pattern characterized by injection of both methamphetamine and heroin. We examined differences in drug injection patterns by demographics, injection behaviors, HIV and HCV status, and overdose.

METHODS

Persons who inject drugs (PWID) were recruited as part of the National HIV Behavioral Surveillance (NHBS) system in Denver, Colorado. We used chi-square statistics to assess differences between those who reported only heroin injection, only methamphetamine injection, and combined heroin and methamphetamine injection. We used generalized linear models to estimate unadjusted and adjusted prevalence ratios to describe the association between drug injection pattern and reported nonfatal overdose in 2015. We also examined changes in the drug reported as most frequently injected across previous NHBS cycles from 2005, 2009, and 2012.

RESULTS

Of 592 participants who completed the survey in 2015, 173 (29.2%) reported only injecting heroin, 123 (20.8%) reported only injecting methamphetamine, and 296 (50.0%) reported injecting both drugs during the past 12 months. Injecting both heroin and methamphetamine was associated with a 2.8 (95% confidence interval: 1.7, 4.5) fold increase in reported overdose in the past 12 months compared with only injecting heroin. The proportion of those reporting methamphetamine as the most frequently injected drug increased from 2.1% in 2005 to 29.6% in 2015 (p < 0.001).

CONCLUSIONS

The rapid increase in methamphetamine injection, and the emergence of combining methamphetamine with heroin, may have serious public health implications.

Drug use generations and patterns of injection drug use: Birth cohort differences among people who inject drugs in Los Angeles and San Francisco, California

OBJECTIVES

A robust literature documents generational trends in drug use. We examined the implications of changing national drug use patterns on drug injection histories of diverse people who inject drugs (PWID).

METHODS

Drug use histories were collected from 776 active PWID in 2011-13. Using descriptive statistics, we examine drug use initiation by year and birth cohort (BC) differences in drug first injected. A multivariate linear regression model of time to injection initiation ([TTII] (year of first injection minus year of first illicit drug use) was developed to explore BC differences.

RESULTS

The first drug injected by BC changed in tandem with national drug use trends with heroin declining from 77% for the pre-1960's BC to 58% for the 1960's BC before increasing to 71% for the 1990's BC. Multivariate linear regression modeling found that shorter TTII was associated with the 1980's/1990's BC (-3.50 years; 95% Confidence Interval [CI]=-0.79, -6.21) as compared to the 1970's BC. Longer TTII was associated with being female (1.65 years; 95% CI=0.40, 2.90), African American (1.69 years; 95% CI=0.43, 2.95), any substance use treatment prior to injection (4.22 years; 95% CI=2.65, 5.79), and prior non-injection use of drug that was first injected (3.29 years; 95% CI=2.19, 4.40).

CONCLUSION

National drug trends appear to influence injection drug use patterns. The prescription opiate drug era is associated with shorter TTII. Culturally competent, demographically and generationally-targeted prevention strategies to combat transitions to drug injection are needed to prevent or shorten upstream increases in risky drug use practices on a national level.

Mitigating the heroin crisis in Baltimore, MD, USA: a cost-benefit analysis of a hypothetical supervised injection facility

Background

In Baltimore, MD, as in many cities throughout the USA, overdose rates are on the rise due to both the increase of prescription opioid abuse and that of fentanyl and other synthetic opioids in the drug market. Supervised injection facilities (SIFs) are a widely implemented public health intervention throughout the world, with 97 existing in 11 countries worldwide. Research has documented the public health, social, and economic benefits of SIFs, yet none exist in the USA. The purpose of this study is to model the health and financial costs and benefits of a hypothetical SIF in Baltimore.

Methods

We estimate the benefits by utilizing local health data and data on the impact of existing SIFs in models for six outcomes: prevented human immunodeficiency virus transmission, Hepatitis C virus transmission, skin and soft-tissue infection, overdose mortality, and overdose-related medical care and increased medication-assisted treatment for opioid dependence.

Results

We predict that for an annual cost of $1.8 million, a single SIF would generate $7.8 million in savings, preventing 3.7 HIV infections, 21 Hepatitis C infections, 374 days in the hospital for skin and soft-tissue infection, 5.9 overdose deaths, 108 overdose-related ambulance calls, 78 emergency room visits, and 27 hospitalizations, while bringing 121 additional people into treatment.

Conclusions

We conclude that a SIF would be both extremely cost-effective and a significant public health and economic benefit to Baltimore City.

A Cost-Benefit Analysis of a Potential Supervised Injection Facility in San Francisco, California, USA

Supervised injection facilities (SIFs) have been shown to reduce infection, prevent overdose deaths, and increase treatment uptake. The United States is in the midst of an opioid epidemic, yet no sanctioned SIF currently operates in the United States. We estimate the economic costs and benefits of establishing a potential SIF in San Francisco using mathematical models that combine local public health data with previous research on the effects of existing SIFs. We consider potential savings from five outcomes: averted HIV and hepatitis C virus (HCV) infections, reduced skin and soft tissue infection (SSTI), averted overdose deaths, and increased medication-assisted treatment (MAT) uptake. We find that each dollar spent on a SIF would generate US$2.33 in savings, for total annual net savings of US$3.5 million for a single 13-booth SIF. Our analysis suggests that a SIF in San Francisco would not only be a cost-effective intervention but also a significant boost to the public health system.

Consistency of self-reported drug use events in a mixed methods study of people who inject drugs

BACKGROUND

Little is known about the consistency of information provided by people who inject drugs (PWID) during quantitative and qualitative interviews in mixed methods studies.

OBJECTIVES

We illustrate the use of the intraclass correlation coefficient, descriptive statistics, and regression to assess the consistency of information provided during a mixed methods study of PWID living in Los Angeles and San Francisco, California, USA.

METHODS

Age of first use of heroin, methamphetamine, marijuana, powder cocaine, and crack cocaine and first injection of heroin, methamphetamine, and powder cocaine were collected during an interviewer administered computer-assisted personal interview followed by an in-depth qualitative interview (n = 102).

RESULTS

Participants were 63% male, racially/ethnically diverse. 80.4% between the ages of 40 and 60 years old, 89% US-born, and 57% homeless. Consistency of self-reported data was adequate for most drug use events. Exact concordance between quantitative and qualitative measures of age of onset ranged from 18.2-50%. Event ordering was consistent across qualitative and quantitative results for 90.2% of participants. Analyses indicated that age of onset for heroin use, heroin injection, and injection of any drug was significantly lower when assessed by qualitative methods as compared to quantitative methods.

CONCLUSION

While inconsistency will emerge during mixed method studies, confidence in the timing and ordering of major types of events such as drug initiation episodes appear to be warranted.