Policing behaviors, safe injection self-efficacy, and intervening on injection risks: Moderated mediation results from a randomized trial

Safe Injection Self-Efficacy is Associated with HCV and HIV Seropositivity Among People Who Inject Drugs in the San Diego-Tijuana Border Region

Safe injection self-efficacy (SISE) is negatively associated with injection risk behaviors among people who inject drugs (PWID) but has not been examined in differing risk environments. We compared responses to a validated SISE scale between PWID in San Diego, California and Tijuana, Mexico, and examine correlates of SISE among PWID in Tijuana. PWID were recruited via street outreach for a longitudinal cohort study from October 2020-September 2021. We compared SISE scale items by city. Due to low variability in SISE scores among San Diego residents, we restricted analysis of factors associated with SISE to Tijuana residents and identified correlates of SISE score levels (low, medium, high) using ordinal logistic regression. Of 474 participants, most were male (74%), Latinx (78%) and Tijuana residents (73%). Mean age was 44. Mean SISE scores among San Diego residents were high (3.46 of 4 maximum) relative to Tijuana residents (mean: 1.93). Among Tijuana residents, White race and having previously resided in San Diego were associated with higher SISE scores. HCV and HIV seropositivity, homelessness, fentanyl use, polysubstance co-injection, and greater injection frequency were associated with lower SISE scores. We found profound inequalities between Tijuana and San Diego SISE, likely attributable to differential risk environments. Associations with fentanyl and polysubstance co-injection, injection frequency, and both HIV and HCV seropositivity suggest that SISE contribute to blood-borne infection transmission risks in Tijuana. SISE reflects an actionable intervention target to reduce injection risk behaviors, but structural interventions are required to change the risk environment.

Safe Injection Self-Efficacy is associated with HCV and HIV seropositivity among people who inject drugs in the San Diego-Tijuana border region

Background

Safe injection self-efficacy (SISE) is negatively associated with injection risk behaviors among people who inject drugs (PWID) but has not been examined in differing risk environments. We compared responses to a validated SISE scale between PWID in San Diego, California and Tijuana, Mexico, and examine correlates of SISE among PWID in Tijuana.

Methods

PWID were recruited via street outreach for a longitudinal cohort study from October 2020 - September 2021. We compared SISE scale items by city. Due to low variability in SISE scores among San Diego residents, we restricted analysis of factors associated with SISE to Tijuana residents and identified correlates of SISE scores (low, medium, high) using ordinal logistic regression.

Results

Of 474 participants, most were male (74%), Latinx (78%) and Tijuana residents (73%). Mean age was 44. Mean SISE scores among San Diego residents were high (3.46 of 4 maximum) relative to Tijuana residents (mean: 1.93). Among Tijuana residents, White race and having previously resided in San Diego were associated with higher SISE scores. HCV and HIV seropositivity, homelessness, fentanyl use, polysubstance co-injection, and greater injection frequency were associated with lower SISE scores.

Conclusions

We found profound inequalities between Tijuana and San Diego SISE, likely attributable to differential risk environments. Associations with fentanyl and polysubstance co-injection, injection frequency, and both HIV and HCV seropositivity suggest that SISE contribute to blood-borne infection transmission risks in Tijuana. SISE reflects an actionable intervention target to reduce injection risk behaviors, but structural interventions are required to intervene upon the risk environment.

Using Novel Approaches to Evaluate Behavioral Interventions: Overlooked Significant HIV Prevention Effects in the HPTN 015 Project EXPLORE

BACKGROUND

Mediated and moderated processes that lead to intervention efficacy may underlie results of trials ruled as nonefficacious. The overall purpose of this study was to examine such processes to explain the findings of one of the largest, rigorously conducted behavioral intervention randomized controlled trials, EXPLORE.

METHODS

Four thousand two hundred ninety-five HIV-negative men who have sex with men (MSM) in the United States were randomized in a 2-armed trial. Participants completed follow-up and an HIV test every 6 months up to 48 months. We used multiple and causal mediation analyses to test 5 mediators, including safer sex self-efficacy and condomless receptive anal sex with HIV-positive or status-unknown partners on our primary outcome (HIV seroconversion). We also examined whether intervention effects on the mediators would be moderated by robust correlates of HIV among MSM, including stimulant use.

RESULTS

There were significant effects of the intervention on all hypothesized mediators. Stimulant use moderated the effect on condomless receptive anal sex In stratified multiple mediation models, we found that among MSM with low stimulant use, the intervention significantly prevented HIV by reducing condomless receptive anal sex with HIV-positive or status-unknown partners. Among MSM with higher stimulant use, there were no indirect effects of the intervention on HIV through any of the hypothesized mediators.

CONCLUSION

The results suggest that the null effect found in the original EXPLORE trial might have occurred as a function of previously unexplored mediated and moderated processes. This study illustrates the value of testing mediated and moderated pathways in randomized trials, even in trials ruled out as nonefficacious.

Assessing Potential Outcomes Mediation in HIV Interventions

Knowledge of causal processes through mediation analysis can help improve the effectiveness and reduce costs of public health programs, like HIV prevention and treatment interventions. Advancements in mediation using the potential outcomes framework provide a method for estimating the causal effect of interventions on outcomes via a mediating variable. The purpose of this paper is to provide practical information about mediation and the potential outcomes framework that can enhance data analysis and causal inference for intervention studies. Causal mediation effects are defined and then estimated using data from an HIV intervention randomized trial among people who inject drugs (PWID) in Ukraine. Results from a potential outcomes mediation analysis show that the intervention had a total causal effect on incident HIV infection such that participants in the experimental group were 36% less likely to become infected during the 12-month study than those in the control arm, but that neither self-efficacy nor network communication mediated this effect. Because neither putative mediator was significant, measurement and confounding issues should be investigated to rule out these mediators. Other putative mediators, such as injection frequency, route of administration, or HIV knowledge can be considered. Future research is underway to examine additional, multiple mediators explaining efficacy of the current intervention and sensitivity to confounding effects.

Sex Discrepancies in the Protective Effect of Opioid Agonist Therapy on Incident Hepatitis C Infection

BACKGROUND

While opioid agonist therapy (OAT) reduces the risk of hepatitis C virus (HCV) acquisition among people who inject drugs (PWID), protective effects may be attenuated in females. We used pooled data from an international collaboration of prospective cohorts to assess sex disparities in HCV incidence among PWID exposed to OAT.

METHODS

Independent predictors of HCV infection were identified using Cox regression models with random effects after accounting for the clustering effect of study sites. Unadjusted and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) are presented in sex-specific analyses.

RESULTS

Among 701 participants exposed to OAT, HCV incidence was 16.5/100 person-years of observation (PYO) (95% CI, 13.1-20.7) in females and 7.6/100 PYO (95% CI, 6.0-9.5) in males (female:male adjusted HR [aHR], 1.80 [95% CI, 1.37-2.22]; P < .001). Factors associated with HCV acquisition among females exposed to OAT included nonwhite race (aHR, 1.79 [95% CI, 1.25-2.56]; P = .001), unstable housing (aHR, 4.00 [95% CI, 3.62-4.41]; P < .001), daily or more frequent injection (aHR, 1.45 [95% CI, 1.01-2.08]; P = .042), and receptive syringe sharing (aHR, 1.43 [95% CI, 1.33-1.53]; P < .001).

CONCLUSIONS

Female PWID exposed to OAT are twice as likely as their male counterparts to acquire HCV. While there is a need for better understanding of sex differences in immune function and opioid pharmacokinetic and pharmacodynamic parameters, structural and behavioral interventions that target women are required to bolster the efficacy of OAT in preventing HCV transmission.

The Experience of Violence Against Women Who Use Injection Drugs: An Exploratory Qualitative Study

BACKGROUND

While literature exists about persons who use injection drugs, few studies explore the experience of women who use these substances. Furthermore, even less research specifically focuses on the lives and experiences of homeless women who use injection drugs. What literature does exist, moreover, is often dated and primarily addresses concerns about infectious disease transmission among these women; and some highlight that these women have lives fraught with violence.

PURPOSE

To update this knowledge and better understand the lives of women who use injection drugs in the Canadian context.

METHODS

We undertook an exploratory qualitative study and we engaged in semi-structured interviews with 31 homeless women who use injection drugs in downtown Ottawa, Canada. We analyzed the data using the principles of applied thematic analysis.

RESULTS

Our data identified that violence pervaded the lives of our participants and that these experiences of violence could be categorized into three main areas: early and lifelong experiences of violence; violence with authority figures (e.g., police, healthcare); and societal violence toward women who use injection drugs.

CONCLUSIONS

We take these findings to mean that, violence toward women is rampant in Canada (not just internationally) and that healthcare workers play a role in propagating and addressing this violence.

Sex differences in the multilevel determinants of injection risk behaviours among people who inject drugs in Tijuana, Mexico

INTRODUCTION AND AIMS

HIV and hepatitis C virus transmission among people who inject drugs (PWID) is fuelled by personal and environmental factors that vary by sex. We studied PWID in Mexico to identify sex differences in multilevel determinants of injection risk.

DESIGN AND METHODS

From 2011 to 2013, 734 PWID (female: 277, male: 457) were enrolled into an observational cohort study in Tijuana. Participants completed interviews on injection and sexual risks. Utilising baseline data, we conducted multiple generalised linear models stratified by sex to identify factors associated with injection risk scores (e.g. frequency of injection risk behaviours).

RESULTS

For both sexes, difficult access to sterile syringes was associated with elevated injection risk (b = 1.24, 95% confidence interval [CI] 1.16-1.33), using syringes from a safe source (e.g. needle exchange programs) was associated with lower injection risk (b = 0.87, 95% CI 0.82-0.94), and for every one-unit increase in safe injection self-efficacy we observed a 20% decrease in injection risk (b = 0.80, 95% CI 0.76-0.84). Females had a higher safe injection self-efficacy score compared to males (median 2.83, interquartile range 2.2-3 vs. median 2.83, interquartile range 2-3; P = 0.01). Among females, incarceration (b = 1.22, 95% CI 1.09-1.36) and police confiscation of syringes in the past 6 months (b = 1.16, 95% CI 1.01-1.33) were associated with elevated injection risk. Among males, sex work (b = 1.16, 95% CI 1.04-1.30) and polysubstance use in the past 6 months (b = 1.22, 95% CI 1.13-1.31) were associated with elevated injection risk.

DISCUSSION AND CONCLUSIONS

Interventions to reduce HIV and hepatitis C virus transmission among PWID in Tijuana should be sex-specific and consider multilevel determinants of injection risk to create safer drug use environments.

Sex Work as a Mediator Between Female Gender and Incident HIV Infection Among People Who Inject Drugs in Tijuana, Mexico

We studied mechanisms driving gender differences in HIV incidence among 651 women and men who inject drugs (PWID) in Tijuana, Mexico, hypothesizing that sex work will mediate the association between female gender and HIV incidence. Of 43 HIV seroconversions occurring between 2011 and 2018, 8.8% were among females and 5.2% among males. HIV incidence density was significantly higher among females versus males (1.75 per 100 person years [PY], 95% CI 1.16-2.66, vs. 0.95 per 100 PY, 95% CI 0.62-1.47). Factors significantly associated with HIV seroconversion were: sex work (adjusted hazard ratio [aHR] = 2.25, 95% CI 1.05-4.80); methamphetamine injection (aHR = 2.30, 95% CI 1.12-4.73); and methamphetamine and heroin co-injection in the past six months (aHR = 2.26, 95% CI 1.23-4.15). In mediation analyses, sex work mediated a substantial proportion (84.3%) of the association between female gender and HIV incidence. Interventions should target female PWID who engage in sex work to reduce gender-related disparities in HIV incidence.

A Mixed Methods Analysis of the Venue-Related Social and Structural Context of Drug Use During Sex Among Male Clients of Female Sex Workers in Tijuana, Mexico

Drug use during sex increases risks for HIV acquisition. Male clients of female sex workers (FSW) represent both a key population at risk for HIV as well as a transmission bridge population. In Tijuana, Mexico, drug use is prevalent and there is a need to understand male clients' drug use during sex with FSW. Characteristics of sex work venues may confer higher risks for drug use, risky sex, and HIV/STI. It is essential to understand the venue-related social and structural factors associated with drug use during sex in order to inform HIV prevention interventions with male clients in this region. We used a Mixed-Methods Sequential Explanatory Design to conduct an enriched examination of drug use during sex among male clients of FSW in Tijuana. Findings from logistic regression analysis showed that drug use during sex was significantly correlated with police harassment (AOR = 4.06, p < .001) and methamphetamine use (AOR = 33.77, p < .001). In-depth interview data provided rich meaning behind and context around the quantitative associations. Social and structural interventions to reduce police harassment, methamphetamine use, and promote condom availability are needed to reduce risks for HIV among male clients of FSW in Tijuana.

Associations between sex work laws and sex workers' health: A systematic review and meta-analysis of quantitative and qualitative studies

BACKGROUND

Sex workers are at disproportionate risk of violence and sexual and emotional ill health, harms that have been linked to the criminalisation of sex work. We synthesised evidence on the extent to which sex work laws and policing practices affect sex workers' safety, health, and access to services, and the pathways through which these effects occur.

METHODS AND FINDINGS

We searched bibliographic databases between 1 January 1990 and 9 May 2018 for qualitative and quantitative research involving sex workers of all genders and terms relating to legislation, police, and health. We operationalised categories of lawful and unlawful police repression of sex workers or their clients, including criminal and administrative penalties. We included quantitative studies that measured associations between policing and outcomes of violence, health, and access to services, and qualitative studies that explored related pathways. We conducted a meta-analysis to estimate the average effect of experiencing sexual/physical violence, HIV or sexually transmitted infections (STIs), and condomless sex, among individuals exposed to repressive policing compared to those unexposed. Qualitative studies were synthesised iteratively, inductively, and thematically. We reviewed 40 quantitative and 94 qualitative studies. Repressive policing of sex workers was associated with increased risk of sexual/physical violence from clients or other parties (odds ratio [OR] 2.99, 95% CI 1.96-4.57), HIV/STI (OR 1.87, 95% CI 1.60-2.19), and condomless sex (OR 1.42, 95% CI 1.03-1.94). The qualitative synthesis identified diverse forms of police violence and abuses of power, including arbitrary arrest, bribery and extortion, physical and sexual violence, failure to provide access to justice, and forced HIV testing. It showed that in contexts of criminalisation, the threat and enactment of police harassment and arrest of sex workers or their clients displaced sex workers into isolated work locations, disrupting peer support networks and service access, and limiting risk reduction opportunities. It discouraged sex workers from carrying condoms and exacerbated existing inequalities experienced by transgender, migrant, and drug-using sex workers. Evidence from decriminalised settings suggests that sex workers in these settings have greater negotiating power with clients and better access to justice. Quantitative findings were limited by high heterogeneity in the meta-analysis for some outcomes and insufficient data to conduct meta-analyses for others, as well as variable sample size and study quality. Few studies reported whether arrest was related to sex work or another offence, limiting our ability to assess the associations between sex work criminalisation and outcomes relative to other penalties or abuses of police power, and all studies were observational, prohibiting any causal inference. Few studies included trans- and cisgender male sex workers, and little evidence related to emotional health and access to healthcare beyond HIV/STI testing.

CONCLUSIONS

Together, the qualitative and quantitative evidence demonstrate the extensive harms associated with criminalisation of sex work, including laws and enforcement targeting the sale and purchase of sex, and activities relating to sex work organisation. There is an urgent need to reform sex-work-related laws and institutional practices so as to reduce harms and barriers to the realisation of health.

Policing practices as a structural determinant for HIV among sex workers: a systematic review of empirical findings

Introduction

Sex workers are disproportionately infected with HIV worldwide. Significant focus has been placed on understanding the structural determinants of HIV and designing related interventions. Although there is growing international evidence that policing is an important structural HIV determinant among sex workers, the evidence has not been systematically reviewed.

Methods

We conducted a systematic review of quantitative studies to examine the effects of policing on HIV and STI infection and HIV-related outcomes (condom use; syringe use; number of clients; HIV/STI testing and access) among cis and trans women sex workers. Databases included PubMed, Embase, Scopus, Sociological Abstracts, Popline, Global Health (OVID), Web of Science, IBSS, IndMed and WHOLIS. We searched for studies that included police practices as an exposure for HIV or STI infection or HIV-related outcomes.

Results

Of the 137 peer-reviewed articles identified for full text review, 14 were included, representing sex workers' experiences with police across five settings. Arrest was the most commonly explored measure with between 6 and 45% of sex workers reporting having ever been arrested. Sexual coercion was observed between 3 and 37% of the time and police extortion between 12 and 28% across studies. Half the studies used a single measure to capture police behaviours. Studies predominantly focused on “extra-legal policing practices,” with insufficient attention to the role of “legal enforcement activities”. All studies found an association between police behaviours and HIV or STI infection, or a related risk behaviour.

Conclusions

The review points to a small body of evidence that confirms policing practices as an important structural HIV determinant for sex workers, but studies lack generalizability with respect to identifying those police behaviours most relevant to women's HIV risk environment.