HIV Risk Practices Among Needle Exchange Users and Nonusers in Chicago

Significant decrease in injection risk behaviours among participants in a needle exchange programme

Background and aims: Sharing of unsterile injection equipment contributes to transmission of hepatitis C virus (HCV), HIV and hepatitis B virus (HBV) among people who inject drugs (PWID) but is largely preventable through needle exchange programmes (NEP). Sweden has been one of the last countries in Europe to scale up access to NEP for PWID, who consequently have high prevalence rates of HCV and HIV. The aim of the study was to investigate demographic and drug-related determinants of injection risk behaviours, sharing of needle/syringe and paraphernalia, and patterns of change over time in subgroups of PWID participating in the Stockholm NEP.Methods: The Stockholm NEP started in 2013 as the first formal NEP in the region. A total of 2860 PWID were included in this prospective open cohort study. The association between demographic and drug-related determinants and injection risk behaviours were analysed at baseline and followed up at 6, 12, 24, 36 and 48 months post-enrolment.Results: The following factors were associated with high levels of injection risk behaviours at inclusion: female gender, homelessness, low education level, younger age, amphetamine use, not in opioid substitution therapy (OST), being HIV negative and being HCV positive. We found an overall significant decrease in injection risk behaviours over time among participants. Not previously investigated in depth, we found that subgroups of participants varied in degrees of injection risk behaviour reduction over time and that women decreased injection risk behaviours faster than men. Enrolment in OST, HIV positive and age <25 years at inclusion were not associated with a decrease in injection risk behaviours over time.Conclusions: In this prospective cohort study over 4 years, we found that NEP participation was associated with a significant decrease in injection risk behaviours.

High-Risk Geographic Mobility Patterns among Young Urban and Suburban Persons who Inject Drugs and their Injection Network Members

Young people in the USA who inject drugs, particularly those at a risk of residence instability, experience the highest incidence of hepatitis C (HCV) infections. This study examined associations between geographic mobility patterns and sociodemographic, behavioral, and social network characteristics of 164 young (ages 18-30) persons who inject drugs (PWID). We identified a potential bridge sub-population who reported residence in both urban and suburban areas in the past year (crossover transients) and higher-risk behaviors (receptive syringe sharing, multiple sex partners) compared to their residentially localized counterparts. Because they link suburban and urban networks, crossover transients may facilitate transmission of HIV and HCV between higher and lower prevalence areas. Interventions should address risk associated with residential instability, particularly among PWID who travel between urban and suburban areas.

Outlier populations: individual and social network correlates of solvent-using injection drug users

Objective

We previously identified a high prevalence of Hepatitis C (HCV) amongst solvent-using injection drug users (S-IDU) relative to other injection drug users within the same locality. Here we incorporated social network variables to better characterize some of the behavioural characteristics that may be putting this specific subgroup of IDU at elevated disease risk.

Methods

A cross-sectional survey of at-risk populations was carried out in Winnipeg, Canada in 2009. Individuals reporting any history of injection drug and/or solvent use were included in the study. Associations between subgroup membership, infection with HCV and HIV and individual and social network variables were examined.

Results

In relation to other IDU, S-IDU were more likely to be infected with HCV, to report ever having shared a syringe, and to associate with other IDU. They were further differentiated in terms of their self-reported sexual orientation, ethnicity and in the injection drugs typically used.

Conclusion

Solvent use stands as a proxy measure of numerous other characteristics that put this group of IDU at higher risk of infection. Provision of adequate services to ostracized subpopulations may result in wider population-level benefits.

Interventions to prevent HIV and Hepatitis C in people who inject drugs: a review of reviews to assess evidence of effectiveness

BACKGROUND

Injecting drug use is a major risk factor for the acquisition and transmission of HIV and Hepatitis C virus (HCV). Prevention of these infections among people who inject drugs (PWID) is critical to reduce ongoing transmission, morbidity and mortality.

METHODS

A review of reviews was undertaken involving systematic literature searches of Medline, Embase, CINAHL, PsychINFO, IBSS and the Cochrane Library (2000-2011) to identify English language reviews regarding the effectiveness of harm reduction interventions in relation to HIV transmission, HCV transmission and injecting risk behaviour (IRB). Interventions included needle and syringe programmes (NSP); the provision of injection paraphernalia; opiate substitution treatment (OST); information, education and counselling (IEC); and supervised injecting facilities (SIFs). Reviews were classified into 'core' or 'supplementary' using critical appraisal criteria, and the strength of review-level evidence was assessed.

RESULTS

Twelve core and thirteen supplementary reviews were included. From these reviews we identified: (i) for NSP: tentative review-level evidence to support effectiveness in reducing HIV transmission, insufficient review-level evidence relating to HCV transmission, but sufficient review-level evidence in relation to IRB; (ii) for OST: sufficient review-level evidence of effectiveness in relation to HIV transmission and IRB, but tentative review-level evidence in relation to HCV transmission; (iii) for IEC, the provision of injection paraphernalia and SIFs: tentative review-level evidence of effectiveness in reducing IRB; and either insufficient or no review-level evidence for these interventions in relation to HIV or HCV transmission.

CONCLUSION

Review-level evidence indicates that harm reduction interventions can reduce IRB, with evidence strongest for OST and NSP. However, there is comparatively little review-level evidence regarding the effectiveness of these interventions in preventing HCV transmission among PWID. Further studies are needed to assess the effectiveness and impact of scaling up comprehensive packages of harm reduction interventions to minimise HIV and HCV transmission among PWID.

Modeling the impact of supra-structural network nodes: The case of anonymous syringe sharing and HIV among people who inject drugs

Networks are well understood as crucial to the diffusion of HIV among injection drug users (IDUs), but quasi-anonymous risk nodes - such as shooting galleries - resist measurement and incorporation into empirical analyses of disease diffusion. Drawing on network data from 767 IDUs in Bushwick, Brooklyn, we illustrate the use of calibrated agent-based models (CABMs) to account for network structure, injection practices, and quasi-anonymous transmission in shooting galleries. Results confirm the importance of network structure and actor heterogeneity to the magnitude and speed of HIV transmission. Models further demonstrate that quasi-anonymous injections in shooting galleries increase the speed of HIV diffusion across the whole network and have the greatest impact on HIV seroconversion levels for IDUs at the network periphery. Shooting galleries are shown to be transmission hubs that operate independently of traceable structural ties, linking otherwise unconnected network components. CABMs potentially increase understandings of HIV diffusion dynamics by infusing computer simulations with empirical data.

Drug-related arrest rates and spatial access to syringe exchange programs in New York City health districts: combined effects on the risk of injection-related infections among injectors

Drug-related law enforcement activities may undermine the protective effects of syringe exchange programs (SEPs) on local injectors' risk of injection-related infections. We explored the spatial overlap of drug-related arrest rates and access to SEPs over time (1995-2006) in New York City health districts, and used multilevel models to investigate the relationship of these two district-level exposures to the odds of injecting with an unsterile syringe. Districts with better SEP access had higher arrest rates, and arrest rates undermined SEPs' protective relationship with unsterile injecting. Drug-related enforcement strategies targeting drug users should be de-emphasized in areas surrounding SEPs.

Longitudinal analysis of the relationship between perceived norms and sharing injection paraphernalia

Despite decline in needle sharing in some countries, many injectors continue to share injection paraphernalia such as cookers and cotton. While individual and structural factors are associated with injection risk behavior, little attention has been given to the influence of social network members, such as norms, on injection paraphernalia sharing. The present study is a longitudinal analysis of the association between perceived norms and sharing syringes and non-syringe injection paraphernalia. Participants were enrolled in the STEP into Action study and reported injection drug use at both baseline and follow-up assessments (n = 398). Results showed that descriptive norms, or believing that peers practiced risky injection behaviors, predicted sharing both syringes and nonsyringe paraphernalia. However, there was no association between injunctive norms (i.e., perceived peer approval) and either syringe or non-syringe paraphernalia sharing. Changing norms may lead to sustained behavior change. Accessible, norms-based interventions are needed to discourage drug injectors from sharing injection paraphernalia.

Evidence for the effectiveness of sterile injecting equipment provision in preventing hepatitis C and human immunodeficiency virus transmission among injecting drug users: a review of reviews

AIMS

To review the evidence on the effectiveness of harm reduction interventions involving the provision of sterile injecting equipment in the prevention of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) transmission among injecting drug users (IDUs). The interventions assessed were needle and syringe programmes (NSP), alternative modes of needle/syringe provision (pharmacies, vending machines and outreach) and the provision of injecting equipment other than needles/syringes.

METHODS

Systematic searches of the English language literature to March 2007 were undertaken to identify systematic, narrative or meta-analytical reviews (also known as a review of reviews) of the impact of interventions on HCV transmission, HIV transmission or injecting risk behaviour (IRB). Critical appraisal criteria classified the reviews as either high quality ('core') or supplementary: a framework based on the quality of reviews, the reviewers' conclusions and the designs/findings of the primary studies was used to derive evidence statements.

RESULTS

Three core and two supplementary reviews of injecting equipment interventions were identified. According to the proposed framework, this study found (a) insufficient evidence to conclude that any of the interventions are effective in preventing HCV transmission; (b) tentative evidence to support the effectiveness of NSP in preventing HIV transmission; (c) sufficient evidence to support the effectiveness of NSP (and tentative evidence of an additional impact of pharmacy NSP) in reducing self-reported IRB; and (d) little to no evidence on vending machines, outreach or providing other injecting equipment in relation to any of the outcomes.

CONCLUSIONS

The evidence is weaker than given credit for in the literature. The lack of evidence for effectiveness of NSP vis-à-vis biological outcomes (HCV and HIV incidence/prevalence) reflects the limitations of studies that have been undertaken to investigate these associations. Particularly for HCV, low levels of IRB may be insufficient to reduce high levels of transmission. New studies are required to identify the intervention coverage necessary to achieve sustained changes in blood-borne virus transmission.

The influence of needle exchange programs on injection risk behaviors and infection with hepatitis C virus among young injection drug users in select cities in the United States, 1994-2004

OBJECTIVE

Our purpose was to assess whether participation in needle exchange programs (NEPs) influenced incident hepatitis C virus (HCV) infection through effects on injection risk behaviors among young injection drug users (IDUs) in the United States.

METHODS

Data were drawn from three multi-site studies carried out in four major cities that enrolled IDUs over the period 1994-2004. Bivariate and multivariate analyses were conducted to assess relationships among sociodemographic characteristics, NEP use, injection risk behaviors, and prevalent or incident HCV infection.

RESULTS

Of the total participants (n=4663), HCV seroprevalence was 37%; among those who initially tested negative and completed follow-up at three, six, or 12 months (n=1288), 12% seroconverted. Nearly half of participants reported NEP (46%) use at baseline. Multivariate results showed no significant relationship between NEP use and HCV seroconversion. Controlling for sociodemographic characteristics, IDUs reporting NEP use were significantly less likely to share needles (aOR=0.77, 95% CI=0.67-0.88). Additionally, controlling for sociodemographic characteristics and program use, sharing needles, sharing other injection paraphernalia, longer injection duration, and injecting daily were all positively related to prevalent infection.

CONCLUSIONS

Our results suggest an indirect protective effect of NEP use on HCV infection by reducing risk behavior.

Utilization patterns and correlates of retention among clients of the needle exchange program in Baltimore, Maryland

NEP effectiveness at a population level depends on several factors, including the number of injection drug users (IDUs) retained, or consistently accessing services. Patterns of retention in the Baltimore Needle Exchange Program (BNEP) from 1994 to 2006 were calculated using enrollment surveys and client records. We used Andersen's Behavioral Model of Health Services Use to frame our examination of factors associated with retention. Client retention was measured in two ways: whether a client returned to the exchange within 12 months of enrollment and how many times a client returned within these 12 months. BNEP clients (N=12,388) were predominantly male (69%), African-American (73%), and >or=age 30 (86%). Nearly two-thirds (64%) of clients returned within 12 months of their first BNEP visit. The median number of return visits per client within 12 months was one (IQR: 0-5). Young age (<30), being married, having an injection drug use history of less than 20 years, and living farther from the BNEP site were characteristics independently associated with both measures of low retention in multivariate analysis. Among younger injectors, geographical proximity was a particularly important predictor of retention. Further insight into the influence of these factors may help in developing programmatic changes that will be effective in increasing retention.

Needle exchange and sexual risk behaviors among a cohort of injection drug users in Chicago, Illinois

OBJECTIVE

To examine the impact of a needle exchange program (NEP) on sexual risk behaviors of injecting drug users (IDUs).

METHODS

: Between 1997 and 2000, 889 IDUs in Chicago were recruited from NEPs and an area with no NEP into a cohort study. They were interviewed and tested for HIV at baseline and 3 annual follow-up visits. Random-effect logistic models were used to compare NEP users and nonusers regarding the number of sex partners, number of unprotected sex acts, and frequency of condom use.

RESULTS

Compared to NEP nonusers, NEP users had a similar number of sex partners over time, but had 49% higher odds of using condoms with their main partners (P = 0.047). At baseline, there was no difference between NEP users and nonusers in episodes of vaginal intercourse, but over time the odds of having a higher number of unprotected instances of vaginal intercourse were reduced by 26% per year for NEP users but only 10% per year for nonusers (P = 0.02).

CONCLUSION

This study suggests that NEP participation may help reduce the absolute risk of HIV sexual transmission.

The social ecology of HIV/AIDS

The reasons that epidemics occur largely are a function of human behaviors and responses to environmental changes, known as the social ecology of infectious diseases. The AIDS epidemic began in remote parts of Central and West Africa and spread from rural areas to urban centers. The epidemic became a global pandemic. Although screening programs and use of antivirals have decreased the likelihood of HIV transmission, these advances have not reached all centers in the developing world. The epidemic continues to grow despite effective treatment because of the absence of a protective vaccine and the continuation of high risk sexual behavior and substance use.

Identifying heterogeneity among injection drug users: a cluster analysis approach

OBJECTIVES

We used cluster analysis to subdivide a population of injection drug users and identify previously unknown behavioral heterogeneity within that population.

METHODS

We applied cluster analysis techniques to data collected in a cross-sectional survey of injection drug users in Winnipeg, Manitoba. The clustering variables we used were based on receptive syringe sharing, ethnicity, and types of drugs injected.

RESULTS

Seven clusters were identified for both male and female injection drug users. Some relationships previously revealed in our study setting, such as the known relationship between Talwin (pentazocine) and Ritalin (methylphenidate) use, injection in hotels, and hepatitis C virus prevalence, were confirmed through our cluster analysis approach. Also, relationships between drug use and infection risk not previously observed in our study setting were identified, an example being a cluster of female crystal methamphetamine users who exhibited high-risk behaviors but an absence or low prevalence of blood-borne pathogens.

CONCLUSIONS

Cluster analysis was useful in both confirming relationships previously identified and identifying new ones relevant to public health research and interventions.

Community coverage and HIV prevention: assessing metrics for estimating HIV incidence through syringe exchange

BACKGROUND

Evaluations of syringe-exchange programme effectiveness that attempt to measure "coverage" by determining the percentage of the at-risk population reached by a programme are insufficient since programmes must provide syringes on a continual basis. Determining the relationship between the extent of programme coverage and its impact (i.e., reductions in disease risk or incidence) is complicated by the lack of controlled trials with cohorts of drug users and instead has to be estimated by imputation, mathematical modelling, or ecological data analysis. This report offers an approach to determine community-wide impact and discusses the limitations of that approach.

METHODS

Easily created programme tracking data were maintained by exchanges in New Haven, CT, USA and Chicago, IL, USA. Data compiled by month quantified the number of unique participants visiting syringe-exchange programmes and the number of syringes distributed. "Coverage", defined either as the percentage of individuals reached or percentage of community syringe need met, was estimated by incorporating measures of the size of the injector population or injection frequency. These measures of coverage are placed in the context of changing programme operations to estimate the effect of these changes on coverage. Finally, data on AIDS cases from New Haven and Chicago were used to estimate the community-wide impact of syringe exchange.

RESULTS

Two mobile syringe-exchange programmes operated with very different exchange policies. Programme data revealed that coverage of individuals rarely exceeded 10% and was higher in New Haven than in Chicago. On the other hand, coverage measured as the percentage of syringe need met was higher at the Chicago exchange that employed the less restrictive policy. The impact of syringe exchange in the two cities was measured by comparing subsequent AIDS cases. The relative reduction in injection-related AIDS cases as a function of all new AIDS diagnoses was 21.7% in New Haven and 41.4% in Chicago.

CONCLUSIONS

A modest investment in the collection of programme data can yield reliable and interpretable information on the extent of programme reach and retention. Limitations to the approach result from the ecological nature of the data and from the need to use data from outside the programme that may be less reliable. For the cases presented here, coverage rates will vary as a function of the programme policies; however, even modest coverage rates - well below those recommended by UNAIDS - can have significant impacts on HIV epidemics. Restrictive policies appeared to increase the coverage if measured only by the proportion of monthly participants and not by the proportion of syringe need met by a programme. More generally, programmes can collect programmatic data and some rapid assessment data (estimates of IDU population and injection frequency) to estimate of the impact of their programmes.

Distributive syringe sharing among young adult injection drug users in five U.S. cities

Blood-borne pathogens such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are transmitted most commonly among injection drug users (IDUs) through the sharing of needles and syringes. Distributive syringe sharing (DSS) (i.e., passing on a used needle/syringe to another IDU) poses the potential risk of transmitting HIV and viral hepatitis to others. We studied the prevalence and correlates of DSS among IDUs enrolled in a randomized behavioral intervention trial designed to reduce behaviors associated with HIV and HCV transmission in five U.S. cities. Among 3129 IDUs ages 15-30 years who completed the baseline visit, 1432 (45.8%) engaged in DSS during the 3 months prior to baseline. Significant correlates of DSS were perception that peer norms condone needle sharing, frequent injection, not obtaining most syringes from needle exchange programs or pharmacies, injecting most frequently in shooting galleries and with sex partners, low perceived risk of HIV from sharing syringes, increased anxiety, low self-esteem, and having unprotected sex. Restricting to only those IDUs who reported not injecting with previously used syringes, similar independent correlates of DSS were found. These findings suggest that interventions to reduce ongoing transmission of blood-borne infections should focus on altering peer norms among networks of young IDUs.

Perceived risk, peer influences, and injection partner type predict receptive syringe sharing among young adult injection drug users in five U.S. cities

OBJECTIVES

This study examined risk factors for receptive syringe sharing (RSS) during illicit drug injection by persons 15-30 years old in five U.S. cities.

METHODS

Participants were recruited through street outreach and respondent-driven referrals in Baltimore, Chicago, Los Angeles, New York, and Seattle between May 2002 and January 2004. Surveys of drug use, sexual behaviors, and correlates were administered through audio computer-assisted self-interviews at baseline and, for the subset of participants who enrolled in an HIV/HCV prevention intervention trial, at 3-months and 6-months post-baseline. The proportions of injections involving RSS at baseline and at follow-up were used as outcomes in multivariate models that adjusted for intervention effects.

RESULTS

At baseline, 54% of 3128 participants reported RSS in the past 3 months. RSS decreased to 21% at 6-months post-baseline for the combined trial arms. Participants were more likely to report RSS if they perceived that their peers were not against RSS and if they injected with sex partners. Lower levels of perceived risk of infection with HIV (baseline, p<.001) or HCV (follow-up, p<.001) through RSS were also significant predictors of greater RSS.

CONCLUSIONS

Perceived risks, peer influences, and type of injection partner were robust predictors of RSS. Perceived risks and peer influences are particularly amenable to intervention efforts that may prevent RSS in this age group.

Determinants of injection drug user (IDU) syringe sharing: the relationship between availability of syringes and risk network member characteristics in Winnipeg, Canada

AIMS

Despite the establishment of syringe exchange programmes, syringe-sharing behaviour remains common among some injection drug users (IDU). Previous studies have identified several individual- and social network-level variables associated with syringe sharing. We examine the extent to which each of these variables is related independently to this behaviour within a diverse study population.

DESIGN, SETTING AND PARTICIPANTS

A cross-sectional survey of 435 IDU conducted between December 2003 and September 2004 in Winnipeg, Canada.

MEASUREMENTS

Individual and social-network variables were obtained from a survey instrument administered through a personal interview. Syringe sharing was defined as receptive syringe sharing in the last 6 months. Logistic regression analysis with generalized estimating equations was used to determine simultaneously the role of individual-level and risk network member-level variables on the odds of syringe sharing.

FINDINGS

Individuals' relationship to a risk network member (sex partner, OR: 15.3 95% CI: 7.6-30.8; family member, OR: 3.4 95% CI: 1.3-9.0) and difficulty of access to syringes (OR: 3.6 95% CI: 1.3-9.9) were predictive of syringe sharing. Dyads who 'often' pooled resources to obtain drugs were at 4.9 times (95% CI: 2.1-11.6) the odds of syringe sharing, while those who 'sometimes' pooled resources were at 2.8 times (95% CI: 1.1-6.7) the odds, compared to those who 'never' pooled resources together.

CONCLUSIONS

Syringe sharing in this population depended on both the availability of clean syringes and social network relationships. Adopting interventions that take into account relationships and behaviours that shape social norms present in networks/dyads would be a necessary prevention strategy alongside the provision of clean syringes.

Needle Exchange and Injection-Related Risk Behaviors in Chicago

OBJECTIVE

To examine whether needle exchange program (NEP) use by injecting drug users (IDUs) affects injection risk behaviors over time.

METHODS

Between 1997 and 2000, 901 IDUs in Chicago were recruited for a cohort study from a multisite NEP and an area with no NEP. Participants were interviewed and tested for HIV at baseline and 3 annual follow-ups. Non-NEP users received HIV prevention services consistent with the Indigenous Leader Outreach Model. Random-effect logistic models were used to compare 5 injection-related risk behaviors between NEP users and nonusers.

RESULTS

The 30-day prevalence of receptive needle sharing decreased from 27.6% at baseline to 10.0% at visit 4 in NEP users and from 47.1% to 20.0% in nonusers. Similar patterns were observed for lending used needles, and NEP users were less likely to reuse their own needles. In multivariate analyses, NEP use was significantly associated with reduced odds of greater than 60% for receptive needle sharing, 45% for lending used needles, and 30% for sharing other injection paraphernalia as well as approximately a 2-fold increase in the odds of always bleaching used needles.

CONCLUSIONS

NEP use facilitates long-term reductions in injection risk practices, and the reductions are in addition to the effects of a behavioral intervention alone.

HIV/hepatitis C virus co-infection in drug users: risk behavior and prevention

Studies of HIV-positive patients have consistently shown that drug users, in particular injection drug users (IDU), are far more likely to have hepatitis C virus (HCV) infection than other patient groups. HIV incidence and prevalence in IDU has declined in recent years, but HCV remains endemic in this population. HCV antibody prevalence among non-injection users of drugs such as heroin and cocaine is between 5 and 30%, although there are scant data on specific transmission risk behavior. The control of HIV/HCV co-infection must address HCV prevention. Epidemiological studies have suggested that HCV prevalence in IDU is subject to various influences, some of which may be modifiable by interventions. However, studies have not shown consistent effects of various prevention strategies on HCV transmission, including studies of HCV screening and education, drug treatment or needle exchange. Although some large cross-sectional studies in regions where needle exchange is available to a large number of drug injectors have reported declining HCV prevalence, the scale of services needed is a matter of considerable debate and has not been systematically quantified. Priorities for research related to the prevention of HIV/HCV co-infection should include estimating the effect on disease occurrence of eliminating specific risk factors, and specifying the level of resources needed to alter HCV incidence.