Associations among drug acquisition and use behaviors, psychosocial attributes, and opioid-involved overdoses.

AIMS: This study sought to develop and assess an exploratory model of how demographic and psychosocial attributes, and drug use or acquisition behaviors interact to affect opioid-involved overdoses. DESIGN: We conducted exploratory and confirmatory factor analysis (EFA/CFA) to identify a factor structure for ten drug acquisition and use behaviors. We then evaluated alternative structural equation models incorporating the identified factors, adding demographic and psychosocial attributes as predictors of past-year opioid overdose. SETTING AND PARTICIPANTS: We used interview data collected for two studies recruiting opioid-misusing participants receiving services from a community-based syringe services program. The first investigated current attitudes toward drug-checking (N = 150). The second was an RCT assessing a telehealth versus in-person medical appointment for opioid use disorder treatment referral (N = 270). MEASUREMENTS: Demographics included gender, age, race/ethnicity, education, and socioeconomic status. Psychosocial measures were homelessness, psychological distress, and trauma. Self-reported drug-related risk behaviors included using alone, having a new supplier, using opioids with benzodiazepines/alcohol, and preferring fentanyl. Past-year opioid-involved overdoses were dichotomized into experiencing none or any. FINDINGS: The EFA/CFA revealed a two-factor structure with one factor reflecting drug acquisition and the second drug use behaviors. The selected model (CFI = .984, TLI = .981, RMSEA = .024) accounted for 13.1% of overdose probability variance. A latent variable representing psychosocial attributes was indirectly associated with an increase in past-year overdose probability (ß = .234, p = .001), as mediated by the EFA/CFA identified latent variables: drug acquisition (ß = .683, p < .001) and drug use (ß = .567, p = .001). Drug use behaviors (ß = .287, p = .04) but not drug acquisition (ß = .105, p = .461) also had a significant, positive direct effect on past-year overdose. No demographic attributes were significant direct or indirect overdose predictors. CONCLUSIONS: Psychosocial attributes, particularly homelessness, increase the probability of an overdose through associations with risky drug acquisition and drug-using behaviors. Further research is needed to replicate these findings with populations at high-risk of an opioid-related overdose to assess generalizability and refine the metrics used to assess psychosocial characteristics.

Injection partnership characteristics and HCV status associations with syringe and equipment sharing among people who inject drugs.

BACKGROUND: Sharing of syringes is the leading transmission pathway for hepatitis C (HCV) infections. The extent to which HCV can spread among people who inject drugs (PWID) is largely dependent on syringe-sharing network factors. Our study aims to better understand partnership characteristics and syringe and equipment sharing with those partners, including measures of relationship closeness, sexual activity, and social support, as well as self and partner HCV status to better inform interventions for young urban and suburban PWID. METHODS: Data are from baseline interviews of a longitudinal network-based study of young (aged 18-30) PWID (egos) and their injection network members (alters) in metropolitan Chicago (n = 276). All participants completed a computer-assisted interviewer-administered questionnaire and an egocentric network survey on injection, sexual, and support networks. RESULTS: Correlates of syringe and ancillary equipment sharing were found to be similar. Sharing was more likely to occur in mixed-gender dyads. Participants were more likely to share syringes and equipment with injection partners who lived in the same household, who they saw every day, who they trusted, who they had an intimate relationship with that included condomless sex, and who provided personal support. PWID who had tested HCV negative within the past year were less likely to share syringes with an HCV positive partner compared to those who did not know their status. CONCLUSION: PWID regulate their syringe and other injection equipment sharing to some extent by sharing preferentially with injection partners with whom they have a close personal or intimate relationship, and whose HCV status they are more likely to know. Our findings underscore the need for risk interventions and HCV treatment strategies to consider the social context of syringe and equipment sharing within partnerships.

Current attitudes toward drug checking services and a comparison of expected with actual drugs present in street drug samples collected from opioid users.

BACKGROUND: The opioid epidemic continues to be associated with high numbers of fatalities in the USA and other countries, driven mainly by the inclusion of potent synthetic opioids in street drugs. Drug checking by means of various technologies is being increasingly implemented as a harm reduction strategy to inform users about constituent drugs in their street samples. We assessed how valued drug checking services (DCS) would be for opioid street drug users given the ubiquity of fentanyl and related analogs in the drug supply, the information they would most value from drug checking, and compared expected versus actual constituent drugs in collected samples. METHODS: A convenience sample of opioid street drug users (N = 118) was recruited from two syringe service exchange programs in Chicago between 2021 and 2022. We administered brief surveys asking about overdose history, whether fentanyl was their preferred opioid, and interest in DCS. We also collected drug samples and asked participants what drug(s) they expected were in the sample. Provided samples were analyzed using LC-MS technology and the results compared to their expected drugs. RESULTS: Participants reported an average of 4.4 lifetime overdoses (SD = 4.8, range = 0-20) and 1.1 (SD = 1.8, range = 0-10) past-year overdoses. A majority (92.1%) believed they had recently used drugs containing fentanyl whether intentionally or unintentionally. Opinions about the desirability of fentanyl were mixed with 56.1% indicating they did not and 38.0% indicating they did prefer fentanyl over other opioids, mainly heroin. Attitudes toward DCS indicated a general but not uniform receptiveness with a majority indicating interest in DCS though sizeable minorities believed DCS was "too much trouble" (25.2%) or there was "no point" in testing (35.4%). Participants were especially inaccurate identifying common cutting agents and potentiating drugs such as diphenhydramine in their samples (sensitivity = .17). CONCLUSIONS: Results affirmed street drug users remain interested in using DCS to monitor their drugs and such services should be more widely available. Advanced checking technologies that provide information on the relative quantities and the different drugs present in a given sample available at point-of-care, would be most valuable but remain challenging to implement.

Network ethnic homophily and injection equipment sharing among Latinx and White non-Latinx people who inject drugs.

Latinx people who inject drugs (PWID) are less likely to engage in injection equipment sharing, but are more vulnerable to injection drug use (IDU)-related morbidity and mortality than Whites. Identifying subgroups of Latinx PWID who do engage in equipment sharing and likely bear the brunt of this health burden is a priority. Ethnic disparities may reflect contextual drivers, including injection networks. Latinx PWID with low ethnic homophily (the proportion of individuals with the same ethnic background) may be more likely to share equipment due to forced distancing from health-protective ethnocultural resources and power imbalances within injection networks. The current study offers a framework and examines how associations between network ethnic homophily and injection equipment sharing differ among 74 Latinx and 170 non-Latinx White PWID in the Chicagoland area (N = 244). Latinx had less homophilous than non-Latinx Whites (p <.001). Ethnic homophily was protective for equipment sharing among Latinx (OR = 0.17, 95%CI [0.77, 0.04], p = .02), but not non-Latinx Whites (OR = 1.66, 95%CI [0.40, 6.93], p = .49). Our findings implicate the need for targeted cultured interventions that focus on Latinx PWID who are more vulnerable to morbidity and mortality, potentially due to less access to ethnic peers.

A Network-Based HIV Prevention Intervention for Tajik Migrant Workers Who Inject Drugs.

We developed and pilot-tested the Migrants' Approached Self-Learning Intervention in HIV/AIDS for Tajiks (MASLIHAT). We recruited 30 Tajik labor migrants who inject drugs in Moscow as peer educators (PEs) to attend the 5-session intervention, then share what they learned with their peers. Each PE recruited two drug-injecting network members for interviewing about their drug and sexual behavior at baseline, 6 weeks, 3 months, and 6 months post-intervention. GEE and mixed effects regression tested time and participant type effects on each outcome. HIV knowledge and risk perception increased among both PEs and network peers, while use of shared syringes, condomless sex, sex with a sex worker, and alcohol use decreased significantly for both groups at 6 weeks and 3 months with a sustained effect through 6 months. The MASLIHAT intervention proved successful in disseminating HIV prevention information and reducing HIV risk behavior over 6 months among both PEs and network members.

RESUMEN: Desarrollamos y realizamos una prueba piloto de la Intervención de autoaprendizaje con enfoque de migrantes en el VIH / SIDA para tayikos (MASLIHAT). Reclutamos a 30 trabajadores migrantes tayikos que se inyectan drogas en Moscú como educadores de pares (EP) para asistir a la intervención de 5 sesiones y luego compartir lo que aprendieron con sus pares. Cada EP reclutó a dos miembros de la red de usuarios de drogas inyectables para entrevistarlos sobre su comportamiento sexual y con las drogas al inicio, 6 semanas, 3 meses y 6 meses después de la intervención. El GEE y la regresión de efectos mixtos probaron el tiempo y los efectos del tipo de participante en cada resultado. El conocimiento del VIH y la percepción del riesgo aumentaron tanto entre los EP como entre los compañeros de la red, mientras que el uso de jeringas compartidas, el sexo sin condón, el sexo con una trabajadora sexual y el consumo de alcohol disminuyeron significativamente para ambos grupos a las 6 semanas y 3 meses con un efecto sostenido durante 6 meses. La intervención MASLIHAT tuvo éxito en la difusión de información sobre la prevención del VIH y en la reducción de las conductas de riesgo del VIH durante 6 meses entre los EP y los miembros de la red.

Egocentric network characteristics of people who inject drugs in the Chicago metro area and associations with hepatitis C virus and injection risk behavior.

BACKGROUND: Hepatitis C (HCV) infection has been rising in the suburban and rural USA, mainly via injection-based transmission. Injection and sexual networks are recognized as an important element in fostering and preventing risky behavior; however, the role of social support networks has received somewhat less attention. METHODS: Using baseline data from an ongoing longitudinal study, we examined the composition and structure of injection drug use (IDU), sex, and social support networks of young people who inject drugs (aged 18-30) and their injection network members. Lasso logistic regression was used to select a subset of network characteristics that were potentially important predictors of injection risk behaviors and HCV exposure. RESULTS: Several measures of IDU, sexual, and support network structure and composition were found to be associated with HCV exposure, receptive syringe sharing (RSS), and ancillary equipment sharing. Gender and sexual relationships were important factors for all risk behaviors. Support network characteristics were also important, notably including a protective effect of majority Hispanic support networks for RSS and HCV exposure. Both IDU network residence heterogeneity and support network geography were associated with injection equipment sharing. CONCLUSIONS: The associations of IDU and support network geography with equipment sharing highlight the need to extend harm reduction efforts beyond urban areas. Greater understanding of support network influences on risk behavior may provide important insights to strengthen the benefits of harm reduction. In considering the probability of HCV transmission, it is important to consider setting and network structures that promote propagation of risk.

Syringe service program-based telemedicine linkage to opioid use disorder treatment: protocol for the STAMINA randomized control trial.

BACKGROUND: A key strategy for mitigating the current opioid epidemic is expanded access to medications for treating opioid use disorder (MOUD). However, interventions developed to expand MOUD access have limited ability to engage opioid users at higher levels of overdose risk, such as those who inject opioids. This paper describes the study protocol for testing STAMINA (Syringe Service Telemedicine Access for Medication-assisted Intervention through NAvigation), an intervention that engages high-risk opioid users at community-based syringe service programs (SSP) and quickly links them to MOUD using a telemedicine platform. METHODS: This randomized control trial will be conducted at three SSP sites in Chicago. All participants will complete an initial assessment with a provider from a Federally Qualified Health Center who can prescribe or refer MOUD services as appropriate. The control arm will receive standard referral to treatment and the intervention arm will receive immediate telemedicine linkage to the provider and (depending on the type of MOUD prescribed) provided transportation to pick up their induction prescription (for buprenorphine or naltrexone) or attend their intake appointment (for methadone). We aim to recruit a total of 273 participants over two years to provide enough power to detect a difference in our primary outcome of MOUD treatment linkage. Secondary outcomes include treatment engagement, treatment retention, and non-MOUD opioid use. Data will be collected using structured interviews and saliva drug tests delivered at baseline, three months, and six months. Fixed and mixed effects generalized linear regression analyses and survival analysis will be conducted to compare the probabilities of a successful treatment linkage between the two arms, days retained in treatment, and post-baseline opioid and other drug use. DISCUSSION: If successful, STAMINA's telemedicine approach will significantly reduce the amount of time between SSP clients' initial indication of interest in the medication and treatment initiation. Facilitating this process will likely lead to stronger additional treatment- and recovery-oriented outcomes. This study is also timely given the need for more rigorous testing of telemedicine interventions in light of temporary regulatory changes that have occurred during the COVID-19 pandemic. TRIAL REGISTRATION: ClinicalTrials.gov (Clinical Trials ID: NCT04575324 and Protocol Number: 1138-0420). Registered 29 September 2020. The study protocol is also registered on the Open Science Framework (DOI 10.17605/OSF.IO/4853 M).

Virological Non-suppression and Its Correlates Among Adolescents and Young People Living with HIV in Southern Malawi.

We examined virological non-suppression (VLN) among youth ages 13-24 years receiving HIV treatment in public health facilities in six southern Malawi districts. We also tested three ART adherence measures to determine how well each identified VLN: pill counts, a Likert scale item, and a visual analogue scale. VLN was defined as HIV RNA > 1000 copies/ml. Of the 209 youth, 81 (39%) were virally non-suppressed. Male gender and stigma were independently associated with VLN; social support and self-efficacy were independently protective. Pill count had the highest positive predictive value (66.3%). Using a pill count cut-off of < 80% nonadherence, 36 (17%) of the youth were non-adherent. Of the adherent, 120 (69%) were viral suppressed. Results indicate the need to address HIV-related stigma and to bolster social support and selfefficacy in order to enhance viral suppression. In the absence of viral load testing, pill count appears the most accurate means to assess VLN.

Improved virologic suppression with HIV subspecialty care in a large prison system using telemedicine: an observational study with historical controls.

Correctional populations have an elevated human immunodeficiency virus (HIV) prevalence, yet many individuals lack access to subspecialty care. Our study showed that HIV-infected inmates had significantly greater virologic suppression and higher CD4 T-lymphocyte counts when managed by a multidisciplinary team of subspecialists conducting clinics via telemedicine. In other studies, these outcomes have been associated with reductions on HIV-related morbidity and mortality, as well as HIV transmission.

Transitions in latent classes of sexual risk behavior among young injection drug users following HIV prevention intervention.

We analyzed data from a large randomized HIV/HCV prevention intervention trial with young injection drug users (IDUs). Using categorical latent variable analysis, we identified distinct classes of sexual behavior for men and women. We conducted a latent transition analysis to test the effect of the intervention on transitions from higher to lower risk classes. Men who were in a high-risk class at baseline who received the intervention were 86 % more likely to be in a low-risk class at follow-up compared to those in the control group (p = 0.025). High-risk intervention participants were significantly more likely to transition to the class characterized by unprotected sex with a main partner only, while low-risk intervention participants were significantly less likely to transition to that class. No intervention effect was detected on the sexual risk behavior of women, or of men who at baseline were having unprotected sex with a main partner only.

Associations among Drug Acquisition and Use Behaviors, Psychosocial Attributes, and Opioid-Involved Overdoses: A SEM Analysis.

Aims: This study sought to develop and assess an exploratory model of how demographic and psychosocial attributes, and drug use or acquisition behaviors interact to affect opioid-involved overdoses. Methods: We conducted exploratory and confirmatory factor analysis (EFA/CFA) to identify a factor structure for ten drug acquisition and use behaviors. We then evaluated alternative structural equation models incorporating the identified factors, adding demographic and psychosocial attributes as predictors of past-year opioid overdose. We used interview data collected for two studies recruiting opioid-misusing participants receiving services from a community-based syringe service program. The first investigated current attitudes toward drug-checking (N = 150). The second was an RCT assessing a telehealth versus in-person medical appointment for opioid use disorder treatment referral (N = 270). Demographics included gender, age, race/ethnicity, education, and socioeconomic status. Psychosocial measures were homelessness, psychological distress, and trauma. Self-reported drug-related risk behaviors included using alone, having a new supplier, using opioids with benzodiazepines/alcohol, and preferring fentanyl. Past-year opioid-involved overdoses were dichotomized into experiencing none or any. Results: The EFA/CFA revealed a two-factor structure with one factor reflecting drug acquisition and the second drug use behaviors. The selected model (CFI = .984, TLI = .981, RMSEA = .024) accounted for 13.1% of overdose probability variance. A latent variable representing psychosocial attributes was indirectly associated with an increase in past-year overdose probability (ß=.234, p = .001), as mediated by the EFA/CFA identified latent variables: drug acquisition (ß=.683, p < .001) and drug use (ß=.567, p = .001). Drug use behaviors (ß=.287, p = .04) but not drug acquisition (ß=.105, p = .461) also had a significant, positive direct effect on past-year overdose. No demographic attributes were significant direct or indirect overdose predictors. Conclusions: Psychosocial attributes, particularly homelessness, increase the probability of an overdose through associations with risky drug acquisition and drug-using behaviors. To increase effectiveness, prevention efforts might address the interacting overdose risks that span multiple functional domains.

Reducing Sample Size While Improving Equity in Vaccine Clinical Trials: A Machine Learning-Based Recruitment Methodology with Application to Improving Trials of Hepatitis C Virus Vaccines in People Who Inject Drugs.

Despite the availability of direct-acting antivirals that cure individuals infected with the hepatitis C virus (HCV), developing a vaccine is critically needed in achieving HCV elimination. HCV vaccine trials have been performed in populations with high incidence of new HCV infection such as people who inject drugs (PWID). Developing strategies of optimal recruitment of PWID for HCV vaccine trials could reduce sample size, follow-up costs and disparities in enrollment. We investigate trial recruitment informed by machine learning and evaluate a strategy for HCV vaccine trials termed PREDICTEE-Predictive Recruitment and Enrichment method balancing Demographics and Incidence for Clinical Trial Equity and Efficiency. PREDICTEE utilizes a survival analysis model applied to trial candidates, considering their demographic and injection characteristics to predict the candidate's probability of HCV infection during the trial. The decision to recruit considers both the candidate's predicted incidence and demographic characteristics such as age, sex, and race. We evaluated PREDICTEE using in silico methods, in which we first generated a synthetic candidate pool and their respective HCV infection events using HepCEP, a validated agent-based simulation model of HCV transmission among PWID in metropolitan Chicago. We then compared PREDICTEE to conventional recruitment of high-risk PWID who share drugs or injection equipment in terms of sample size and recruitment equity, with the latter measured by participation-to-prevalence ratio (PPR) across age, sex, and race. Comparing conventional recruitment to PREDICTEE found a reduction in sample size from 802 (95%: 642-1010) to 278 (95%: 264-294) with PREDICTEE, while also reducing screening requirements by 30%. Simultaneously, PPR increased from 0.475 (95%: 0.356-0.568) to 0.754 (95%: 0.685-0.834). Even when targeting a dissimilar maximally balanced population in which achieving recruitment equity would be more difficult, PREDICTEE is able to reduce sample size from 802 (95%: 642-1010) to 304 (95%: 288-322) while improving PPR to 0.807 (95%: 0.792-0.821). PREDICTEE presents a promising strategy for HCV clinical trial recruitment, achieving sample size reduction while improving recruitment equity.

Sexual risk behavior associated with transition to injection among young non-injecting heroin users.

The aim of this study was to investigate the effects of transitioning from non-injection heroin use to injection drug use on sexual risk behavior. Non-injecting heroin users age 16-30 were enrolled from 2002 to 2005, and were re-interviewed at 6-month intervals for up to three years; 561 participants completed at least one follow-up interview. The majority of participants were non-Hispanic (NH) Black (54 %), 23 % were Hispanic, and 21 % were NH white. During follow-up, 154 participants (27.5 %) transitioned to injecting drugs. Logistic regression analyses were conducted using generalized estimating equations (GEE) to estimate the effect of transition to injection drug use on changes in sexual risk behavior during follow-up. Transition to injection drug use during follow-up was associated with increased likelihood of sexual risk behavior, especially for men. Harm reduction efforts that focus on preventing initiation or return to injection among non-injecting drug users may also ameliorate HIV sexual risk behaviors.

Community-, network-, and individual-level predictors of uptake of medication for opioid use disorder among young people who inject drugs and their networks: A multilevel analysis.

BACKGROUND: Opioid use has been increasing at alarming rates over the past 15 years, yet uptake of medication for opioid use disorder (MOUD) remains low. Much of the research on individual characteristics predicting MOUD uptake is equivocal, and there is a dearth of research on setting-level and network-level characteristics that predict MOUD uptake. Towards a more holistic, multilevel understanding, we explore individual-level, network-level, and community-level characteristics associated with MOUD uptake. METHODS: Baseline data from a longitudinal study of young people who inject drugs and their injection and support network members living in Chicago (N = 165) was used to conduct cross-sectional multilevel logistic regression analyses to examine associations between MOUD uptake and a set of potential predictors at the individual-, network-, and community-levels that were chosen based on theoretical relevance or support from previous empirical studies. RESULTS: Stigma at both the individual and community levels was significantly associated with MOUD uptake (though in different directions). Greater individual-level stigma was associated with a higher likelihood of MOUD uptake, while having a more normatively stigmatizing community environment was associated with a lower likelihood of MOUD uptake. Using heroin and cocaine simultaneously and having a larger support network were associated with a greater likelihood of MOUD uptake. CONCLUSIONS: The present study's holistic, multilevel approach identified three individual-level characteristics, one network-level characteristic, and one community-level characteristic associated with MOUD uptake. However, more research is needed examining multilevel predictors, to help with developing interventions addressing barriers to MOUD use at multiple levels of influence.

Feasibility Study of Using Mobile Phone-Based Experience Sampling to Assess Drug Checking by Opioid Street Drug Users.

Background: To date, evaluations of take-home fentanyl (and/or benzodiazepine) test strip use - the most common form of drug checking services - and potential effects on overdose risk have relied on retrospective accounts for some preceding time period, usually a week to several months. Such accounts, however, are subject to recall and memory biases. This pilot study assessed the feasibility of using experiential sampling to collect daily information in situ on drug checking and associated overdose risk reduction - the primary outcomes - among a sample of street opioid users and compared the results to retrospective reports. Methods: We recruited 12 participants from a Chicago-based syringe services program. Participants were 18 years of age or older, reported using opioids purchased on the street 3+ times per week in the past month, and had an available Android mobile phone. A phone-based app was programmed to collect daily drug checking information and provided to each participant along with a supply of fentanyl and benzodiazepine test strips and instructions for use over 21 days. Comparable retrospective data were collected via follow-up in-person surveys at the conclusion of daily report collection. Results: We found a reasonably high rate of daily reporting (63.5%) with participants submitting reports on 160 "person-days" out of 252 possible days. Participants submitted daily reports an average of 13 of 21 days. Reports of test strip use frequency varied between the retrospective and daily reports with a relatively higher percentage of days/time using test strips obtained from the daily reports. We also found higher proportions reporting overdose risk reduction behaviors on the daily reports compared with the retrospective reviews. Conclusions: We believe the results support using daily experience sampling to collect information on drug checking behaviors among street drug users. Although resource intensive in comparison to retrospective reports, daily reporting potentially provides more detailed information on test strip use and its association with overdose risk reduction and, ultimately, fewer overdoses. Needed are larger trials and validation studies of daily experience sampling to identify the optimum protocol for collecting accurate information on drug checking and overdose risk reduction behavior.

HIV and hepatitis C risk among Tajik migrant workers who inject drugs in Moscow.

Background . The HIV epidemic in Eastern Europe and Central Asia continues to grow with most infections occurring in high-risk groups including people who inject drugs and their sexual partners. Labor migrants from this region who inject drugs while in Russia are at especially high HIV risk. Methods . We recruited 420 male Tajik migrant workers who inject drugs in Moscow for a peer-education HIV prevention intervention trial. Participants were interviewed about their sex and drug use behavior and tested for HIV and hepatitis C prior to the intervention. Results . Over half of the men reported injecting with a previously used syringe in the past month. Many men reported condomless sex (42%), multiple sex partners (30%), and sex with sex workers (42%). Only 17% had ever been tested for HIV. Despite substantial risk behavior, prevalence rates of HIV (6.8%) and HCV (2.9%) although elevated were lower than expected when compared to estimates of prevalence among PWID at the national level in Tajikistan. Risk behavior in diaspora varied across the men’s regional area of origin in Tajikistan and occupation in Moscow with HIV prevalence rates highest among those working at the bazaars. Conclusion . Tajik male migrants who inject drugs in Moscow are at heightened risk for HIV and hepatitis C. Evidence-based prevention approaches and messaging that specifically address the drug- and sex-related risk behavior of migrants from different parts of Tajikistan, employment sectors within the destination city, and socio-demographic background are needed.

Feasibility study of using mobile phone-based experience sampling to assess drug checking by opioid street drug users.

BACKGROUND: To date, evaluations of take-home fentanyl (and/or benzodiazepine) test strip use - the most common form of drug checking services - and potential effects on overdose risk have relied on retrospective accounts for some preceding time period, usually a week to several months. Such accounts, however, are subject to recall and memory biases. This pilot study assessed the feasibility of using experiential sampling to collect daily information in situ on drug checking and associated overdose risk reduction - the primary outcomes - among a sample of street opioid users and compared the results to retrospective reports. METHODS: We recruited 12 participants from a Chicago-based syringe services program. Participants were 18 years of age or older, reported using opioids purchased on the street 3 + times per week in the past month, and had an available Android mobile phone. A phone-based app was programmed to collect daily drug checking information and provided to each participant along with a supply of fentanyl and benzodiazepine test strips and instructions for use over 21 days. Comparable retrospective data were collected via follow-up in-person surveys at the conclusion of daily report collection. RESULTS: We found a reasonably high rate of daily reporting (63.5%) with participants submitting reports on 160 "person-days" out of 252 possible days. Participants submitted daily reports an average of 13 of 21 days. Reports of test strip use frequency varied between the retrospective and daily reports with a relatively higher percentage of days/time using test strips obtained from the daily reports. We also found higher proportions reporting overdose risk reduction behaviors on the daily reports compared with the retrospective reviews. CONCLUSIONS: We believe the results support using daily experience sampling to collect information on drug checking behaviors among street drug users. Although resource intensive in comparison to retrospective reports, daily reporting potentially provides more detailed information on test strip use and its association with overdose risk reduction and, ultimately, fewer overdoses. Needed are larger trials and validation studies of daily experience sampling to identify the optimum protocol for collecting accurate information on drug checking and overdose risk reduction behavior.

HIV and Hepatitis C Risk among Tajik Migrant Workers Who Inject Drugs in Moscow.

The human immunodeficiency virus (HIV) epidemic in Eastern Europe and Central Asia continues to grow with most infections occurring in high-risk groups including people who inject drugs and their sexual partners. Labor migrants from this region who inject drugs while in Russia are at especially high HIV risk. Male Tajik migrant workers who inject drugs in Moscow (N = 420) were interviewed prior to a randomized trial of the Migrants' Approached Self-Learning Intervention in HIV/AIDS (MASLIHAT) peer-education HIV-prevention intervention. Participants were interviewed about their sex and drug use behavior and tested for HIV and hepatitis C (HCV) prior to the intervention. Only 17% had ever been tested for HIV. Over half of the men reported injecting with a previously used syringe in the past month, and substantial proportions reported risky sexual behavior. Prevalence rates of HIV (6.8%) and HCV (2.9%) were elevated, although lower than expected when compared to estimates of prevalence among people who inject drugs at the national level in Tajikistan. Risk behavior in diaspora varied across the men's regional area of origin in Tajikistan and occupation in Moscow, with HIV prevalence rates highest among those working at the bazaars. Evidence-based prevention approaches and messaging that specifically address the drug- and sex-related risk behavior of migrants with varying backgrounds are needed.

Social-spatial network structures among young urban and suburban persons who inject drugs in a large metropolitan area.

Background: It is estimated that there are 1.5% US adult population who inject drugs in 2018, with young adults aged 18-39 showing the highest prevalence. PWID are at a high risk of many blood-borne infections. Recent studies have highlight the importance of employing the syndemic approach to study opioid misuse, overdose, HCV and HIV, along with the social and environmental contexts where these interrelated epidemics occur in already marginalized communities. Social interactions and spatial contexts are important structural factors that are understudied. Methods: Egocentric injection network and geographic activity spaces for young (aged 18-30) PWID and their injection, sexual, and social support network members (i.e., where reside, inject drugs, purchase drugs, and meet sex partners) were examined using baseline data from an ongoing longitudinal study (n=258). Participants were stratified based on the location of all place(s) of residence in the past year i.e., urban, suburban, and transient (both urban and suburban) to i) elucidate geospatial concentration of risk activities within multi-dimensional risk environments based on kernel density estimates; and ii) examine spatialized social networks for each residential group. Results: Participants were mostly non-Hispanic white (59%); 42% were urban residents, 28% suburban, and 30% transient. We identified a spatial area with concentrated risky activities for each residence group on the West side of Chicago where a large outdoor drug market area is located. The urban group (80%) reported a smaller concentrated area (14 census tracts) compared to the transient (93%) and suburban (91%) with 30 and 51 tracts, respectively. Compared to other areas in Chicago, the identified area had significantly higher neighborhood disadvantages (e.g., higher poverty rate, p <0.001). Significant ( p <0.01 for all) differences were observed in social network structures: suburban had the most homogenous network in terms of age and residence, transient participants had the largest network (degree) and more non-redundant connections. Conclusion: We identified concentrated risk activity spaces among PWID from urban, suburban, and transient groups in a large outdoor urban drug market area, which highlights the need for considering the role of risk spaces and social networks in addressing the syndemics in PWID populations.

A Novel Index Measure of Housing-related Risk as a Predictor of Overdose among Young People Who Inject Drugs and Injection Networks.

Background: For people who inject drugs (PWID), housing instability due to decreasing housing affordability and other factors (e.g., loss of housing due to severed relational ties, evictions due to drug use) results in added pressure on an already vulnerable population. Research has shown that housing instability is associated with overdose risk among PWID. However, the construct of housing instability has often been operationalized as a single dimension (e.g., housing type, homelessness, transience). We propose a multi-dimensional measure of housing instability risk and examine its association with drug overdose to promote a more holistic examination of housing status as a predictor of overdose. Methods: The baseline data from a network-based, longitudinal study of young PWID and their networks living in metropolitan Chicago, Illinois was analyzed to examine the relationship between a housing instability risk index-consisting of five dichotomous variables assessing housing instability-and lifetime overdose count using negative binomial regression. Results: We found a significant positive association between the housing instability risk score and lifetime overdose count after adjusting for 12 variables. Conclusions: Our results support the practical utility of a multi-dimensional measure of housing instability risk in predicting overdose and highlight the importance of taking a holistic approach to addressing housing instability when designing interventions.