Associations between housing stability and injecting frequency fluctuations: findings from a cohort of people who inject drugs in Montréal, Canada

Individual Heterogeneity and Trends in Hepatitis C Infection Risk Among People Who Inject Drugs: A Longitudinal Analysis

Hepatitis C virus (HCV) causes substantial morbidity and mortality, particularly among people who inject drugs (PWID). While elimination of HCV as a public health problem may be possible through treatment-as-prevention, reinfection can attenuate the impact of treatment scale-up. There is a need to better understand the distribution and temporal trends in HCV infection risk, including among HCV-seropositive individuals who will be eligible for treatment and at risk for subsequent reinfection. In this analysis of 840 seronegative and seropositive PWID in Baltimore, MD USA, we used random forest methods to develop a composite risk score of HCV infection from sociodemographic and behavioural risk factors. We characterised the individual heterogeneity and temporal trajectories in this composite risk score using latent class methods and compared that index with a simpler, conventional measure, injection drug use frequency. We found that 15% of the population remained at high risk of HCV infection and reinfection by the composite metric for at least 10 years from study enrolment, while others experienced transient periods of moderate and low risk. Membership in this high-risk group was strongly associated with higher rates of HCV seroconversion and post-treatment viraemia, as a proxy of reinfection risk. Injection frequency alone was a poor measure of risk, evidenced by the weak associations between injection frequency classes and HCV-associated outcomes. Together, our results indicate HCV infection risk is not equally distributed among PWID nor well captured by injection frequency alone. HCV elimination programmes should consider targeted, multifaceted interventions among high-risk individuals to reduce reinfection.

Rapid Assessment Amid an Injection Drug Use-Driven HIV Outbreak in Massachusetts' Merrimack Valley: Highlights from a Case Study

Illicitly manufactured fentanyl within the drug supply has substantially increased opioid-related overdose deaths and driven infectious disease outbreaks among people who use drugs (PWUD). Local jurisdictions often lack the data and tools necessary to detect and translate such moments into actionable and effective responses. Informed by a risk environment framework, this case study adopted a mixed-methods design spanning two rapid assessment studies with PWUD in Lowell (n = 90) and Lawrence (n = 40), Massachusetts, during an HIV outbreak (2017, Study 1) and following the outbreak (2019, Study 2). Survey responses (n = 130) were summarized by computing descriptive statistics, ethnographic field notes were reviewed, and qualitative interviews (n = 34) were thematically analyzed to contextualize quantitative findings. Study 1 participants reported constrained syringe access, high injecting frequency, syringe reuse, and unsafe syringe disposal practices, and uncovered entrenched social and structural factors exacerbating existing substance use and HIV risks: housing instability, limited harm reduction supplies and services (e.g., MOUD access), and tensions between law enforcement and PWUD. Following the outbreak and substantial local investments in harm reduction and treatment infrastructures, Study 2 participants indicated lower injection risk reporting fewer syringe reuse episodes, improved syringe disposal practices, high frequency of naloxone administration at recent overdoses, frequent testing for HIV and HCV, and greater engagement with syringe services programs. A rapid assessment approach to fentanyl's emergence and a concomitant HIV outbreak provided time-sensitive, critical insights and identified needed and local response strategies. However, unless social and structural risk factors are also addressed, community vulnerability to future HIV outbreaks remains.

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.

Evaluating the prevalence of current hepatitis C infection and treatment among Aboriginal and Torres Strait Islander peoples who inject drugs in Australia: The ETHOS engage study

INTRODUCTION

Evaluating progress towards hepatitis C virus (HCV) elimination among Aboriginal and Torres Strait Islander peoples is critical given the disproportionate burden of infection. We examined factors associated with current HCV infection and self-reported treatment among Aboriginal and Torres Strait Islander (hereafter referred to as Aboriginal peoples) and non-Aboriginal peoples who inject drugs (PWID) in Australia.

METHODS

ETHOS Engage is an observational cohort study of PWID attending drug treatment and needle and syringe programs in Australia. Participants underwent point-of-care HCV RNA testing (Xpert HCV RNA Viral Load Fingerstick) and completed a questionnaire including self-reported history of HCV treatment.

RESULTS

Between May 2018 and June 2021, 2395 participants were enrolled and 555 (23%) identified as Aboriginal (median age 42 years, 58% were men, 63% injected drugs in last month, 76% ever incarcerated). HCV RNA prevalence was 23% among Aboriginal PWID (24% in 2018-2019 and 21% in 2019-2021; p = 0.44), and 21% among non-Aboriginal PWID (24% in 2018-2019 and 16% in 2019-2021; p < 0.001). Self-reported HCV treatment was 65% among Aboriginal PWID (63% in 2018-2019 and 69% in 2019-2021; p = 0.30), and 70% among non-Aboriginal PWID (67% in 2018-2019 and 75% in 2019-2021; p < 0.001). Among Aboriginal PWID, current HCV infection was associated with recently injecting drugs and receiving opioid agonist treatment, and self-reported HCV treatment was negatively associated with younger age, homelessness and recently injecting drugs.

DISCUSSION AND CONCLUSIONS

Equitable access to HCV care and prevention is needed to ensure Australia meets its elimination targets among Aboriginal PWID.

Sexual and drug use risk behaviour trajectories among people treated for recent HCV infection: the REACT study

INTRODUCTION

Exploration of sexual and drug use behaviours following treatment for recent hepatitis C virus (HCV) is limited. This analysis modelled behavioural trajectories following treatment for recent HCV and assessed reinfection.

METHODS

Participants treated for recent HCV in an international trial (enrolled 2017-2019) were followed at 3-monthly intervals for up to 2 years to assess longitudinal behaviours. Population-averaged changes were assessed using generalized estimating equations. Distinct behavioural trajectories were identified using group-based trajectory modelling. HCV reinfection incidence was calculated using person-years (PY) of observation.

RESULTS

During the follow-up of 212 participants (84% gay and bisexual men [GBM]; 69% HIV; 26% current injecting drug use [IDU]), behavioural trajectories for IDU and stimulant use (past month) did not change. However, population-averaged decreases in the likelihood of daily IDU (adjusted odds ratio [AOR] 0.83; 95% CI 0.72, 0.95) and opioid use (AOR 0.84; 95% CI 0.75, 0.93) were observed. Among GBM, behavioural trajectories for chemsex did not change. Population-averaged decreases in condomless anal intercourse with casual male partners (CAI-CMP) (AOR 0.95; 95% CI 0.90, 0.99) and group-sex (AOR 0.86; 95% CI 0.80, 0.93) were observed, but masked distinct trajectories. While a proportion had a decreased probability of CAI-CMP (23%) and group-sex (59%) post-treatment, a substantial proportion retained a high probability of these behaviours. High HCV reinfection incidence was observed for the sustained high probability IDU (33.0/100 PY; 95% CI 17.7, 61.3) and chemsex (23.3/100 PY; 95% CI 14.5, 37.5) trajectories.

CONCLUSIONS

Limited sexual and drug use behavioural change was observed following treatment for recent HCV, supporting access to surveillance and (re)treatment.

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.

Acute injection-related infections requiring hospitalisation among people who inject drugs: Clinical features, microbiology and management

INTRODUCTION

People who inject drugs are at risk of hospitalisation with injection-related infections (IRI). We audited the clinical features, microbiology and management of IRI at a tertiary service in Melbourne to describe the burden and identify quality improvement opportunities.

METHODS

We performed retrospective review of IRI admissions from January 2017 to April 2019. We extracted admissions where ICD-10 codes or triage text suggested injecting drug use, and the diagnosis suggested IRI. We reviewed these for eligibility and extracted data using a standardised form. We performed mixed-effects logistic regression to determine predictors of unplanned discharge.

RESULTS

From 574 extracted candidate admissions, 226 were eligible, representing 178 patients. Median age was 41 years (interquartile range 36-47), 66% (117/178) male and 49% (111/226) had unstable housing. Over 50% (96/178) had a psychiatric diagnosis and 35% (62/178) were on opioid agonist therapy (OAT) on admission. Skin and soft tissue infection was the most common IRI (119/205, 58%), followed by bacteraemia (36/205, 18%) and endocarditis (26/205, 13%). Management included addictions review (143/226, 63%), blood-borne virus screening (115/226, 51%), surgery (77/226, 34%) and OAT commencement (68/226, 30%). Aggression events (54/226, 15%) and unplanned discharge (69/226, 30%) complicated some admissions. Opioid use without OAT was associated with almost 3-fold increased odds of unplanned discharge compared to no opioid use (odds ratio 2.90, 95% confidence interval 1.23, 6.85, p = 0.015).

DISCUSSION AND CONCLUSION

Comorbidities associated with IRI may be amenable to opportunistic intervention during hospitalisation. Further research is needed to develop optimal models of care for this vulnerable patient group.

Primary care embedded within permanent supportive housing for people who use substances: A qualitative study examining healthcare access in Vancouver, Canada

Marginally housed people who use drugs and alcohol (PWUD/A) face barriers in accessing healthcare services, which may be improved by providing healthcare in housing settings. This case study examines the experiences of healthcare access amongst PWUD/A who live in a permanent supportive housing model in Vancouver, Canada. This model has an embedded multidisciplinary clinic providing in-reach services. Thirty participants were recruited via posters placed throughout the building and semi-structured qualitative interviews were conducted remotely. Interviews were conducted with participants who accessed onsite care regularly (n = 15) and those who do not (n = 15). Data were analysed to identify both a priori and emerging themes. Participants who accessed the onsite clinic reported benefiting from stigma-free care. Close proximity and convenience of drop-in appointments enabled participants to engage with healthcare services more consistently, though hours of operation and privacy concerns were barriers for others. Participants who did not use the onsite clinic highlighted the importance of continuity of care with their pre-existing primary care team, particularly if their clinic was in close geographic proximity. However, they also described utilising these services for urgent health needs or as an occasional alternative source of care. Shared perspectives across all participants emphasised the importance of low-barrier services, including medication delivery, convenience and positive therapeutic relationships. Our findings suggest that embedding access to primary care within supportive housing benefits PWUD/A who have previously encountered barriers to healthcare access. This model could be implemented to prevent utilisation of acute healthcare resources and improve health outcomes amongst PWUD/A.

Patterns of homelessness and housing instability and the relationship with mental health disorders among young people transitioning from out-of-home care: Retrospective cohort study using linked administrative data

Objectives

The study examined the relationship between mental health, homelessness and housing instability among young people aged 15–18 years old who transitioned from out-of-home in 2013 to 2014 in the state of Victoria, Australia with follow-up to 2018. We determined the various mental health disorders and other predictors that were associated with different levels of homelessness risk, including identifying the impact of dual diagnosis of mental health and substance use disorder on homelessness.

Methodology

Using retrospective de-identified linked administrative data from various government departments we identified various dimensions of homelessness which were mapped from the European Topology of Homelessness (ETHOS) framework and associated mental health variables which were determined from the WHO ICD-10 codes. We used ordered logistic regression and Poisson regression analysis to estimate the impact of homelessness and housing instability respectively.

Results

A total homelessness prevalence of 60% was determined in the care-leaving population. After adjustment, high risk of homelessness was associated with dual diagnosis of mental health and substance use disorder, intentional self-harm, anxiety, psychotic disorders, assault and maltreatment, history of involvement with the justice system, substance use prior to leaving care, residential and home-based OHC placement and a history of staying in public housing.

Conclusions

There is clearly a need for policy makers and service providers to work together to find effective housing pathways and integrated health services for this heterogeneous group of vulnerable young people with complex health and social needs. Future research should determine longitudinally the bidirectional relationship between mental health disorders and homelessness.

The contribution of unstable housing to HIV and hepatitis C virus transmission among people who inject drugs globally, regionally, and at country level: a modelling study

BACKGROUND

A considerable proportion of people who inject drugs are unstably housed. Although unstable housing is associated with HIV and HCV infection among people who inject drugs, its contribution to transmission is unknown. We estimated the global and national proportions of incident HIV and HCV infections among people who inject drugs attributed to housing instability from 2020 to 2029.

METHODS

In this modelling study, we developed country-level models of unstable housing and HIV and HCV transmission among people who inject drugs in 58 countries globally, calibrated to country-specific data on the prevalences of HIV and HCV and unstable housing. Based on a recently published systematic review, unstably housed people who inject drugs were assumed to have a 39% (95% CI 6-84) increased risk of HIV transmission and a 64% (95% CI 43-89%) increased risk of HCV transmission. We used pooled country-level estimates from systematic reviews on HCV and HIV prevalence in people who inject drugs. Our models estimated the transmission population attributable fraction (tPAF) of unstable housing to HIV and HCV transmission among people who inject drugs, defined as the percentage of infections prevented from 2020 to 2029 if the additional risk due to unstable housing was removed.

FINDINGS

Our models were produced for 58 countries with sufficient data (accounting for >66% of the global people who inject drugs population). Globally, we project unstable housing contributes 7·9% (95% credibility interval [CrI] 2·3-15·7) of new HIV infections and 11·2% (7·7-15·5) of new HCV infections among people who inject drugs from 2020 to 2029. Country-level tPAFs were strongly associated with the prevalence of unstable housing. tPAFs were greater in high-income countries (HIV 17·2% [95% CrI 5·1-30·0]; HCV 19·4% [95% CrI 13·8-26·0]) than in low-income or middle-income countries (HIV 6·6% [95% CrI 1·8-13·1]; HCV 8·3% [95% CrI 5·5-11·7]). tPAFs for HIV and HCV were highest in Afghanistan, Czech Republic, India, USA, England, and Wales where unstable housing contributed more than 20% of new HIV and HCV infections.

INTERPRETATION

Unstable housing is an important modifiable risk factor for HIV and HCV transmission among people who inject drugs in many countries. The study emphasises the importance of implementing initiatives to mitigate these risks and reduce housing instability.

FUNDING

National Institute for Health Research and National Institute of Allergy and Infectious Diseases and National Institute for Drug Abuse.

Acceptability, feasibility, and pilot results of the tele-harm reduction intervention for rapid initiation of antiretrovirals among people who inject drugs

BACKGROUND

People who inject drugs (PWID) have been a marginalized and a stigmatized population since the beginning of the AIDS epidemic and have not experienced the same life-changing benefits of antiretroviral therapy as others. Tele-Harm Reduction (THR) is a telehealth-enhanced, harm reduction intervention, delivered within a trusted SSP venue. It aims to facilitate initiation of care and achieve rapid HIV viral suppression among PWID living with HIV.

METHODS

In this mixed-methods study, we employed the Practical, Robust, Implementation and Sustainability Model (PRISM) implementation science framework to identify multilevel barriers and facilitators to implementing the THR intervention. Focus groups (n = 2, 16 participants), stakeholder interviews (n = 7) and in-depth interviews were conducted with PWID living with HIV (n = 25). In addition, to assess feasibility and acceptability, we pilot tested the THR intervention and reported viral suppression at 6 months.

RESULTS

Focus groups and stakeholder interviews revealed system and organizational level barriers to implementation including requirements for identification and in person visits, waiting times, stigma, case management inexperience, multiple electronic health records, and billing. A potential facilitator was using telehealth for case management and initial provider visit. In the in depth interviews conducted with PWID living with HIV, participants expressed that the SSP creates a convenient, comfortable, confidential environment for delivering multiple, non-stigmatizing PWID-specific services. 35 PWID living with HIV were enrolled in the pilot study, 35 initiated antiretroviral therapy, and 25 (78.1%) were virally suppressed at six months.

CONCLUSION

Rooted in harm reduction, the THR intervention shows promise in being an acceptable and feasible intervention that may facilitate engagement in HIV care and viral suppression among PWID.

Injecting frequency trajectories and hepatitis C virus acquisition: Findings from a cohort of people who inject drugs in Montréal, Canada

BACKGROUND

Frequent injecting increases hepatitis C (HCV) acquisition risk among people who inject drugs (PWID). However, few studies have examined how temporal fluctuations in injecting frequency may effect HCV infection risk. Thus, this study examined HCV incidence according to injecting frequency trajectories followed by PWID over one year in Montréal, Canada.

METHODS

At three-month intervals from March 2011 to June 2016, HCV-uninfected PWID (never infected or cleared infection) enrolled in the Hepatitis Cohort (HEPCO) completed interviewer-administered questionnaires and HCV testing. At each visit, participants reported the number of injecting days (0-30 days) for each of the past three months. In previous work, using group-based trajectory modeling, we identified five injecting frequency trajectories followed by participants over one year (months 1-12 of follow-up), including sporadic, infrequent, increasing, decreasing, and frequent injecting. In this study, we estimated group-specific HCV incidence (months 1-63 of follow-up) using posterior probabilities to assign participants to their most likely trajectory group.

RESULTS

Of 386 participants (mean age=40, 82% male, 48% never HCV-infected), 72 acquired HCV during 893 person-years of follow-up. HCV incidence for the whole study sample was 8.1 per 100 person-years (95%CI=6.4-10.1). Trajectory group-specific HCV incidences were highest for those injecting drugs with decreasing (23.9, 14.4-37.5) or increasing frequency (16.0, 10.1-24.3), intermediate for those injecting at consistently high frequency (10.2, 5.4-17.8), and lowest for those injecting infrequently (3.9, 2.2-6.5) or sporadically (4.3, 2.2-7.6).

CONCLUSION

Results suggest that PWID at highest HCV risk are those injecting at high frequency, either transitorily (increasing, decreasing injecting) or consistently (frequent injecting). This study highlights changes in injecting frequency as a potentially important dimension to consider among the factors leading to HCV acquisition. Clinical and public health interventions tailored to PWID with different injecting frequency profiles may contribute to HCV prevention.

The uptake of foil from needle and syringe provision services and its role in smoking or snorting heroin among people who inject drugs in Scotland

BACKGROUND

In the UK, legislation was implemented in 2014 allowing needle and syringe provision (NSP) services to offer foil to people who inject drugs (PWID) to encourage smoking rather than injecting. This paper aims to examine the association between foil uptake and smoking or snorting heroin among PWID. This is the first large scale national study to examine foil uptake and smoking or snorting heroin among PWID post legislative change.

METHOD

Data from 1453 PWID interviewed via Scotland's Needle Exchange Surveillance Initiative in 2017-2018 were analysed using multivariate logistic regression.

RESULTS

Overall, 36% of PWID had obtained foil from NSP services in the past six months. The odds of smoking or snorting heroin were higher among those who had obtained foil (Adjusted Odds Ratio (AOR) 3.79 (95% CI 2.98-4.82) p<0.001) compared to those who had not. Smoking or snorting heroin was associated with lower odds of injecting four or more times daily (AOR 0.60 (95% CI 0.40-0.90) p = 0.012) and injecting into the groin or neck (AOR 0.57 (95% CI 0.46-0.71) p<0.001) but increased odds of having had a skin and soft tissue infection (SSTI) (AOR 1.49 (95% CI 1.17-1.89) p = 0.001) and having experienced an overdose (AOR 1.58 (95% CI 1.18-2.10) p = 0.002) both in the past year.

CONCLUSION

The promotion of smoking drugs via foil provision from NSP services may contribute to the package of harm reduction measures for PWID alongside the provision of injecting equipment. We found that those in receipt of foil were more likely to smoke or snort heroin, and that smoking or snorting heroin was associated with a lower likelihood of some risky injecting behaviours, namely frequent injecting and injecting into the groin or neck. But it remains uncertain if the provision of foil can lead to a reduction in health harms, such as SSTI and overdose. Future research is needed to understand PWID motivations for smoking drugs, obtaining foil from NSP services, and its uses particularly among polydrug users.

Progress Towards Elimination of Hepatitis C Infection Among People Who Inject Drugs in Australia: The ETHOS Engage Study

BACKGROUND

Evaluating progress towards hepatitis C virus (HCV) elimination is critical. This study estimated prevalence of current HCV infection and HCV treatment uptake among people who inject drugs (PWID) in Australia.

METHODS

The Enhancing Treatment of Hepatitis C in Opioid Substitution Settings Engage is an observational study of PWID attending drug treatment clinics and needle and syringe programs (NSPs). Participants completed a questionnaire including self-reported treatment history and underwent point-of-care HCV RNA testing (Xpert HCV Viral Load Fingerstick; Cepheid).

RESULTS

Between May 2018 and September 2019, 1443 participants were enrolled (64% injected drugs in the last month, 74% receiving opioid agonist therapy [OAT]). HCV infection status was uninfected (28%), spontaneous clearance (16%), treatment-induced clearance (32%), and current infection (24%). Current HCV was more likely among people who were homeless (adjusted odds ratio, 1.47; 95% confidence interval, 1.00-2.16), incarcerated in the previous year (2.04; 1.38-3.02), and those injecting drugs daily or more (2.26; 1.43-2.42). Among those with previous chronic or current HCV, 66% (n = 520/788) reported HCV treatment. In adjusted analysis, HCV treatment was lower among females (.68; .48-.95), participants who were homeless (.59; .38-.96), and those injecting daily or more (.51; .31-.89). People aged ≥45 years (1.46; 1.06-2.01) and people receiving OAT (2.62; 1.52-4.51) were more likely to report HCV treatment.

CONCLUSIONS

Unrestricted direct-acting antiviral therapy access in Australia has yielded high treatment uptake among PWID attending drug treatment and NSPs, with a marked decline in HCV prevalence. To achieve elimination, PWID with greater marginalization may require additional support and tailored strategies to enhance treatment.

Socioeconomic stability is associated with lower injection frequency among people with distinct trajectories of injection drug use

BACKGROUND

Little is known about how socioeconomic circumstances relate to injection frequencies among people who inject drugs (PWID) with diverse trajectories of injection. We aimed to characterize trajectories of injection drug use in a community-based sample of PWID over 7.5 years and to investigate the extent to which two modifiable factors reflecting socioeconomic stability-stable housing and stable income-relate to injection frequencies across distinct trajectories.

METHODS

HEPCO is an open, prospective cohort study of PWID living in Montréal with repeated follow-up at three-month or one-year intervals. Self-reported data on injection frequency, housing and income are collected at each visit. Injection frequency was defined as the number of injection days (0-30), reported for each of the past three months. Using group-based trajectory modeling, we first estimated average trajectories of injection frequency. Then, we estimated the trajectory group-specific average shift upward or downward associated with periods of stable housing and stable income relative to periods when these conditions were unstable.

RESULTS

Based on 19,527 injection frequency observations accrued by 529 participants followed over 2011-2019 (18.3% female, median age: 41), we identified five trajectories of injection frequency: three characterized by sustained injection at different frequencies (28% infrequent; 19% fluctuating; 19% frequent), one by a gradual decline (12%), and another by cessation (28%). Periods of stable housing and stable income were each independently associated with a lower injection frequency, on average, in all five trajectory groups (2.2-7.5 fewer injection days/month, depending on the factor and trajectory group).

CONCLUSION

Trajectories of injection drug use frequency were diverse and long-lasting for many PWID. Despite this diversity, socioeconomic stability was consistently associated with a lower injection frequency, emphasizing the close relationship between access to fundamental necessities and injection patterns in all PWID, irrespective of whether they are on a path to cessation or sustained injecting.

Predictors of hepatitis C treatment outcomes in a harm reduction-focused primary care program in New York City

Background

The social determinants of health that influence steps in the entire Hepatitis C Virus (HCV) treatment cascade must be identified to achieve HCV elimination goals. This project aimed to evaluate the association of these factors with HCV treatment completion and return for sustained virologic response (SVR) testing.

Methods

We used retrospective cohort data from our primary care-based HCV treatment program that provides comprehensive harm reduction care to those who use or formerly used drugs. Among persons who began direct-acting antiviral HCV treatment between December 2014 and March 2018, we identified two outcomes: HCV treatment completion and return for SVR assessment 12 weeks after treatment end. Several predictors were ascertained including sociodemographic information, substance use, psychiatric symptoms and history, housing instability, and HCV treatment regimen. We then evaluated associations between predictors and outcomes using univariate and multivariable statistical methods.

Results

From a cohort of 329 patients treated in an urban primary care center, multivariable analysis identified housing instability as a single significant predictor for HCV treatment completion (odds ratio [OR]: 0.3; 95% confidence interval [CI]: 0.1–0.9). Among patients completing treatment, 226 (75%) returned for SVR assessment; the sole predictor of this outcome was Medicaid as primary insurance (compared to other insurances; OR 0.3; 0.1–0.7).

Conclusions

Innovative strategies to help unstably housed persons complete HCV treatment are urgently needed in order to reach HCV elimination targets. Educational and motivational strategies should be developed to promote individuals with Medicaid in particular to return for SVR viral load testing, a critical post-treatment component of the HCV treatment cascade.

Trial registration Not applicable.