Traveling young injection drug users at high risk for acquisition and transmission of viral infections

Continued Transmission of HIV Among Young Adults Who Inject Drugs in San Francisco: Still Room for Improvement

We measured HIV incidence rate, trend and risk factors in 564 HIV-negative young people (< 30 years) who inject drugs (PWID) in San Francisco between 2000 and 2014. HIV incidence was 0.93/100 person-years (PY; 95% CI 0.50, 1.73). Incidence varied between 0.62/100 PY in 2000-2002 and 1.06/100 PY in 2012-2014 (P for trend = 1.0). HIV incidence varied significantly (P < 0.01) by race/ethnicity: among Hispanics it was 8.19/100 PY (95% CI 3.41, 19.68), African-Americans 4.59/100 PY (95% CI 1.15, 18.37), and Whites 0.26/100 PY (95% CI 0.06, 1.03). Male participants who reported sex with men (MSM) had higher HIV incidence (2.63/100 PY; 95% CI 1.31, 5.25) compared to males who did not report MSM (0.50/100 PY; 95% CI 0.12, 1.99) (P = 0.01). Despite an overall stable HIV incidence trend, incidence was elevated among African-American and Hispanic PWID, and men who have sex with men. Addressing prevention needs in these key populations is critical for the goal of eliminating HIV transmission.

Development and validation of a novel scale for measuring interpersonal factors underlying injection drug using behaviours among injecting partnerships

BACKGROUND

People who inject drugs with sexual partners or close friends have high rates of syringe/ancillary equipment sharing and HIV and hepatitis C virus (HCV) infection. Although evidence suggests that interpersonal factors underlie these higher risk profiles, there is no quantitative measure of how interpersonal factors operate within injecting relationships. We aimed to develop and validate a quantitative scale to assess levels of injecting drug-related interpersonal factors associated with risky injecting behaviours within injecting partnerships.

METHODS

We conducted qualitative interviews with 45 people who inject drugs (PWID) who reported having injecting partners to inform item development, and tested these items in a quantitative study of 140 PWID from San Francisco, USA, to assess internal reliability (Cronbach's alpha) and validity (convergent, and discriminant validity).

RESULTS

With results from the qualitative interview data, we developed the Interpersonal Dynamics in Injecting Partnerships (IDIP) scale with 54 final items for 5 subscales of injecting-related interpersonal factors. Exploratory factor analysis revealed 5 factors ("trust", "power", "risk perception", "intimacy", and "cooperation") with eigenvalues of 14.32, 6.18, 3.55, 2.46, and 2.14, explaining 57% of the variance, and indicating good internal reliability (alpha: 0.92-0.68). Strong convergent validity was observed in bivariate logistic regression models where higher levels of trust, intimacy, and cooperation within partnerships were positively associated with partners sharing needles and injecting equipment, whereas higher levels of power and risk perception were negatively associated with partners sharing needles and injecting equipment.

CONCLUSIONS

These findings offer strong evidence that the IDIP scale provides a psychometrically sound measure of injecting drug-related interpersonal dynamics. This measurement tool has the potential to facilitate additional investigations into the individual and collective impact of trust, intimacy, power, cooperation, and risk perception on injection drug using behaviours and engagement in HIV and HCV testing and treatment among PWID in a variety of settings.

High Concomitant Misuse of Fentanyl in Subjects on Opioid Maintenance Treatment

BACKGROUND

Concomitant opioid misuse is an increasing problem in opioid maintenance treatment as it interferes with treatment success.

OBJECTIVE

Therefore, the rates of concomitant fentanyl misuse in opioid maintained patients were investigated.

METHODS

We conducted a cross-sectional study which consisted in collecting data via urine samples and questionnaires in Germany. Urine samples of patients on opioid maintenance treatment were gathered and fentanyl concentrations were measured from 2008 to 2012. An anonymous questionnaire provided data on the consumption of fentanyl as concomitant drug. Data were analyzed with descriptive statistics and group differences were calculated using the Chi-Square test.

RESULTS

Among the total sample (urine probes of 960 patients), 6.8% opioid maintained patients had positive urine samples for fentanyl and 37.9% reported concomitant fentanyl misuse (401 of these patients filled out the questionnaire). A significant age-related association of concomitant fentanyl misuse was identified in the urine analyses (χ² = 7.489; p = .024) and also in the questionnaire data (χ² = 11.899, p = .003), indicating that young age increased the probability of fentanyl consumption. Patients receiving methadone had the highest rates of concomitant fentanyl misuse with 18.4% according to urine analysis. In addition, the results show that patients who are on diamorphine are significantly less likely to misuse fentanyl.

CONCLUSIONS

Fentanyl is a frequently used concomitant drug. Especially young patients and patients taking methadone are at high risk. Because of the life-threatening consequences of fentanyl overdose, patients taking fentanyl should be intensively medically surveilled.

The role of social networks and geography on risky injection behaviors of young persons who inject drugs

BACKGROUND

Little is known about young persons who inject drugs (PWID), who are increasingly from suburban communities and predominantly non-Hispanic white.

METHODS

We conducted a cross-sectional personal network (egocentric) and geographic study of young PWID and their drug-using, sexual, and support network members in 2012-13 in metropolitan Chicago, Illinois, U.S.

RESULTS

We enrolled 164 young (median age=26), mostly male (65%), non-Hispanic white PWID (71%), with a self-reported HCV prevalence of 13%. Many (59%) reported multiple residences (i.e., were transient) in the past year, 45% of whom reported living in both urban and suburban places (i.e., were cross-over transients). In multivariable analyses that adjusted for participant and network member characteristics, (1) large injection networks were more common among homeless participants; and (2) syringe sharing was (a) highest among cross-over transients compared to suburban (OR=4.19 95% CI 1.69-10.35) and urban only residents (OR=2.91 95% CI 1.06-8.03), (b) higher among HCV-unknown compared HCV-negative participants (OR=4.62 95% CI 1.69-10.35), (c) more likely with network members who were cross-over transients compared to urban (OR=4.94, 95% CI 2.17-11.23) and (d) less likely with network members with HCV-unknown compared to HCV-negative status (OR=0.4 95% CI 0.19-0.84).

CONCLUSIONS

We identified homelessness as a significant risk factor for large networks and cross-over transience as a significant risk factor for syringe sharing. Further research is needed to understand the role of geographic factors promoting higher risk among these crossover transient PWID.

Acceptability of Global Positioning System technology to survey injecting drug users' movements and social interactions: a pilot study from San Francisco, USA

BACKGROUND

Despite potential applications for improving health services using GPS technology, little is known about ethical concerns, acceptability, and logistical barriers for their use, particularly among marginalized groups.

OBJECTIVES

We garnered the insights of people who inject drug (PWID) in San Francisco on these topics.

METHODS

PWID were enrolled through street-outreach (n=20) and an ongoing study (n=4) for 4 focus group discussions. Participants also completed a self-administered questionnaire on demographic characteristics and their numbers and types of interactions with other PWID.

RESULTS

Median age was 30.5 years, majorities were male (83.3%) and white (68.2%). Most interacted with other PWID for eating meals and purchasing drugs over the last week; fewer reported interactions such as sexual contact, drug treatment, or work. Participants identified several concerns about carrying GPS devices, including what authorities might do with the data, that other PWID and dealers may suspect them as informants, and adherence to carrying and use. Most felt concerns were surmountable with detailed informed consent on the purpose of the study and practical ways to carry, charge, and hide devices.

CONCLUSIONS

PWID felt data collection on their movements and social interactions with other PWID using GPS can be acceptable with addressing specific concerns. The technology is now in hand to greatly expand the ability to monitor health conditions with respect to the environment and improve the location of prevention, care, and treatment facilities to serve hard to reach, mobile, and hidden populations.

Preference, acceptability and implications of the rapid hepatitis C screening test among high-risk young people who inject drugs

Background

People who inject drugs (PWID) are at highest risk for hepatitis C virus (HCV) infection, yet many remain unaware of their infection status. New anti-HCV rapid testing has high potential to impact this.

Methods

Young adult (<30 years) active PWID were offered either the rapid OraQuick® or standard anti-HCV test involving phlebotomy, then asked to complete a short questionnaire about testing perceptions and preferences. Sample characteristics, service utilization, and injection risk exposures are assessed with the HCV testing choice as the outcome, testing preferences, and reasons for preference.

Results

Of 129 participants: 82.9% (n = 107) chose the rapid test. There were no significant differences between those who chose rapid vs. standard testing. A majority (60.2%) chose the rapid test for quick results; most (60.9%) felt the rapid test was accurate, and less painful (53.3%) than the tests involving venipuncture.

Conclusions

OraQuick® anti-HCV rapid test was widely accepted among young PWID. Our results substantiate the valuable potential of anti-HCV rapid testing for HCV screening in this high risk population.

Políticas de redução de danos no Brasil

Considerando a disseminação da epidemia de HIV e o controle de sua transmissão entre usuários de drogas injetáveis (UDI), estratégias de redução de danos foram incorporadas em diversos países, incluindo o Brasil. Considerando a emergência das drogas como tema central na agenda governamental, especialmente o crack, o presente artigo registra e discute as práticas observadas em um programa de pesquisa e atenção aos UDI: o UFO. Foram considerados aspectos tais como acesso e adesão do usuário, dificuldades de financiamento, sustentabilidade e avaliação de resultados. As etapas do estudo envolveram pesquisa documental, observação sistemática e entrevistas com informantes-chave. Destacamos características do UFO que poderiam contribuir para políticas de redução de danos no cenário brasileiro. O programa estudado se apresenta como um exemplo exitoso de iniciativas de redução de danos, obtendo sucesso no acesso e adesão desse grupo, favorecendo seu acesso aos serviços de saúde e prevenção de riscos associados ao uso de drogas.

Activity spaces among injection drug users in San Francisco

BACKGROUND

Representations of activity spaces, defined as the local areas within which people move or travel in the course of their daily activities, are unexplored among injection drug users (IDUs). The purpose of this paper is to use an activity space framework to study place and drug user health.

METHODS

Data for this analysis is from an epidemiological study of street-recruited IDUs in San Francisco (N=1084). Study participants reported geographic intersections of where they most often slept at night, hung out during the day, and used drugs during a 6 month time period. We used GIS software to construct and map activity space routes of street-based network paths between these intersections. We further identified if syringe exchange program (SEP) locations intersected with, participant activity space routes. We used logistic regression to estimate associations between activity space variables and HIV serostatus, syringe sharing, and non-fatal overdose, after adjusting for individual and Census tract covariates.

RESULTS

Mean activity space distance for all participants was 1.5miles. 9.6% of participants had a SEP located along their activity space. An increase in activity space distance was associated with a decrease in odds of being HIV positive. An increase in residential transience, or the number of different locations slept in by participants in a 6 month time period, was associated with higher odds of syringe sharing. Activity space distance was not independently associated with overdose or syringe sharing.

DISCUSSION

Research that locates individuals in places of perceived importance is needed to inform placement and accessibility of HIV and overdose prevention programs. More attention needs to be given to the logistics of collecting sensitive geospatial data from vulnerable populations as well as how to maximize the use of GIS software for visualizing and understanding how IDUs interact with their environment.

HCV infection prevalence lower than expected among 18-40-year-old injection drug users in San Diego, CA

San Diego, California shares the world's busiest land border crossing with Tijuana, Mexico-a city where 95 % of injection drug users (IDUs) test hepatitis C virus (HCV) antibody-positive. Yet, little is known about the prevalence and risk behaviors for HCV among IDUs in San Diego. In 2009-2010, 18-40-year-old IDUs in San Diego County completed a risk assessment interview and serologic testing for HCV and HIV infection. Recruitment involved respondent-driven sampling, venue-based sampling at a syringe exchange program, and convenience sampling. Correlates of HCV infection were identified by multivariable logistic regression. Among 510 current IDUs, 26.9 % (95 % CI 23.0-30.7 %) and 4.2 % (95 % CI 2.4-5.9 %) had been infected with HCV and HIV, respectively. Overall, median age was 28 years; 74 % were male; 60 % white and 29 % Hispanic; and 96 % were born in the U.S. Median years of injecting was 6; 41 % injected daily; 60 % injected heroin most often; 49 % receptively shared syringes and 68 % shared other injection paraphernalia; and only 22 % reported always using new syringes in the past 3 months. Two thirds had ever traveled to Mexico and 19 % injected in Mexico. HCV infection was independently associated with sharing injection paraphernalia (adjusted odds ratio [AOR] = 1.69) and SEP use (AOR = 2.17) in the previous 3 months, lifetime history of drug overdose (AOR = 2.66), and increased years of injecting (AOR = 2.82, all P values <0.05). Controlling for recruitment method did not alter results. HCV infection prevalence among IDUs in San Diego was modest compared to other US cities and much lower than Tijuana. Given that known individual-level HCV risk factors were common in San Diego, the city's lower HCV prevalence might be due to differences in social and structural factors between the cities.

Injecting risk behavior among traveling young injection drug users: travel partner and city characteristics

Young injection drug users (IDUs), a highly mobile population, engage in high levels of injecting risk behavior, yet little is understood about how such risk behavior may vary by the characteristics of the cities to which they travel, including the existence of a syringe exchange program (SEP), as well as travel partner characteristics. In 2004-2005, we conducted a 6-month prospective study to investigate the risk behavior of 89 young IDUs as they traveled, with detailed information gathered about 350 city visits. In multivariable analyses, travel to larger urban cities with a population of 500,000-1,000,000 was significantly associated with injecting drugs (adjusted odds ratio (AOR) = 3.71; 95 % confidence interval (CI), 1.56-8.82), ancillary equipment sharing (AES; AOR = 7.05; 95 % CI, 2.25-22.06) and receptive needle sharing (RNS; AOR = 5.73; 95 % CI, 1.11-27.95), as compared with visits to smaller cities with populations below 50,000. Region of the country, and the existence of a SEP within the city visited, were not independently associated with injecting drugs, AES, or RNS during city visits. Traveling with more than one injecting partner was associated with injecting drugs during city visits (AOR = 2.77; 95 % CI, 1.46-5.27), when compared with traveling alone. Additionally, both non-daily and daily/almost daily alcohol use during city visits were associated with AES (AOR = 3.37; 95 % CI, 1.42-7.68; AOR = 3.03; 95 % CI, 1.32-6.97, respectively) as compared with no alcohol consumption. Traveling young IDUs are more likely to inject when traveling with other IDUs and to engage in higher risk injection behavior when they are in large cities. Risk behavior occurring in city visits, including equipment sharing and alcohol consumption, suggests further need for focused interventions to reduce risk for viral infection among this population.

Predictors of Transience Among Homeless Emerging Adults

This study identified predictors of transience among homeless emerging adults in three cities. A total of 601 homeless emerging adults from Los Angeles, Austin, and Denver were recruited using purposive sampling. Ordinary least squares regression results revealed that significant predictors of greater transience include White ethnicity, high school degree or equivalent, homeless residence in the 6 months prior to the study, longer period of homelessness, history of arrest and juvenile detention, earning income through informal sources, history of physical abuse, alcohol/drug addiction, and resilience characteristics. Quantitative findings were expanded upon with data from in-depth interviews with 145 of these homeless emerging adults regarding their reasons and motivations for transience. Identifying predictors of transience will facilitate customizing interventions that, when needed, aim to stabilize homeless emerging adults, prevent their mobility, and/or offer mobile services to them on the road.

Hepatitis B and C infection in international travelers

BACKGROUND

Hepatitis B and C virus (HBV and HCV) cause significant morbidity and mortality worldwide. With the rise in international travel over the last three decades, many travelers are at risk of HBV and HCV infection.

METHODS

This review focuses on the epidemiology of HBV and HCV in international travelers, the modes of transmission, and the prevention of infection in travelers.

RESULTS

The risk of HBV and HCV infection varies widely and depends on the prevalence of the destination country, the duration of travel, and the activities undertaken while abroad. Travelers commonly undertake high-risk activities that place them at risk of both HBV and HCV infection. Poor uptake of preventative health measures and poor adherence to health recommendations are also common. The monthly incidence of HBV infection for long-term travelers to endemic countries ranges from 25 to 420 per 100,000 travelers. HBV infection can be prevented through timely vaccination of travelers. HBV vaccination is safe and efficacious with protective levels of antibodies achieved in >90% of recipients. Information regarding the risk of HCV acquisition is scarce and until recently was limited to case reports following medical interventions.

CONCLUSIONS

This review demonstrates international travelers are at risk of HBV and HCV infection and provides evidence-based information enabling health practitioners to provide more appropriate pre-travel advice. HBV vaccination should be considered in all travelers to countries with a moderate to high HBV prevalence (HBsAg ≥ 2%) and the risk and benefits discussed with the individuals in consultation with the health practitioner. There is no duration of travel without risk of HBV infection. However, it is apparent that those travelers with a longer duration of travel are at greatest risk of HBV infection (ie, expatriates). Travelers should also receive advice regarding the modes of transmission and the activities that place them at risk of both HBV and HCV infection.

Predictors of alcohol use among rural drug users after disclosure of hepatitis C virus status

OBJECTIVE

Alcohol consumption dramatically increases the risk of liver damage among those with hepatitis C virus (HCV) infection, yet the impact of HCV status disclosure and standard informational counseling on alcohol use among rural drug users remains poorly understood.

METHOD

In this prospective study, 503 rural Appalachian drug users were recruited using respondent-driven sampling. Participants were tested for HCV antibodies, and data on sociodemographic characteristics, lifetime and past-30-day drug and alcohol use, and psychiatric disorders were collected by interviewer-administered questionnaires. A total of 470 participants returned after 6 months for follow-up; however,4 of those had no history of alcohol use, thus leaving a final sample size of 466. Multivariate negative binomial regression was used to determine the effect of disclosure of HCV status and posttest counseling on alcohol consumption at follow-up.

RESULTS

Despite an overall decrease in drinking frequency in the cohort, those who were HCV-positive were drinking at a frequency similar to their HCV-negative counterparts at follow-up, despite posttest counseling informing them of the risks of alcohol use with an HCV diagnosis (adjusted incidence rate ratio = 1.07, 95% CI [0.72, 1.61]). Significant predictors of increased days of alcohol use after 6 months included baseline alcohol use, baseline marijuana use, and meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for antisocial personality disorder. Those using OxyContin at baseline had significantly fewer days of alcohol use at follow-up.

CONCLUSIONS

HCV status disclosure and standard informational counseling alone do not curtail drinking among HCV-positive drug users in the rural setting. Targeted interventions with regard to alcohol use are warranted in order to mitigate the damage of the HCV epidemic.

Hazardous alcohol consumption among young adult IDU and its association with high risk behaviors

BACKGROUND

Heavy alcohol consumption has been associated with risk-taking behaviors in intravenous drug users (IDU). However, limited information exists on the relationship between alcohol use and injecting and sexual risk in young adult IDU (<30 years) who are at risk for hepatitis C virus (HCV) and HIV infection.

METHODS

We conducted a cross-sectional study of young adult IDU in San Francisco (2006-2012) who had not previously tested positive for HCV. Participants completed a structured interview and HCV testing. We examined whether hazardous drinking (Alcohol Use Disorders Test-Consumption [AUDIT-C] 3-9 for women and 4-9 for men) and probable dependent drinking (AUDIT-C 10-12) levels were associated with injecting and sexual risk behaviors and HCV status, indicated by adjusted odds ratios (AOR) in separate models controlling for potential confounders.

RESULTS

Of the 326 participants, 139 (42.6%) were hazardous drinkers and 82 (25.2%) were probable dependent drinkers; thus over two-thirds evidenced problem drinking. Being a hazardous drinker was significantly associated with injecting drug residue from another's drug preparation equipment (AOR 1.93). Probable dependent drinking was significantly associated with sharing non-sterile drug preparation equipment (AOR 2.59), and inversely, with daily/near daily injecting (AOR 0.42). Both heavy drinking levels were associated with having ≥2 sexual partners (AOR 2.43 and 2.14). Drinking category was not associated with HCV test results.

CONCLUSION

The young adult IDU reported consuming alcohol at very high levels, which was associated with some unsafe sexual and injecting behaviors. Our study demonstrates the urgent need to intervene to reduce alcohol consumption in this population.

Predictors and effects of alcohol use on liver function among young HCV-infected injection drug users in a behavioral intervention

BACKGROUND & AIMS

Hepatitis C virus (HCV) screening can provide opportunities to reduce disease progression through counseling against alcohol use, but empirical data on this issue are sparse. We determined the efficacy of a behavioral intervention in reducing alcohol use among young, HCV-infected injection drug users (IDUs) (n=355) and assessed whether changes in liver enzymes were associated with changes in alcohol consumption.

METHODS

Both the intervention and attention-control groups were counseled to avoid alcohol use, but the intervention group received enhanced counseling. Logistic regression, ANOVA, and continuous time Markov models were used to identify factors associated with alcohol use, changes in mean ALT and AST levels, and change in alcohol use post-intervention.

RESULTS

Six months post-intervention, alcohol abstinence increased 22.7% in both groups, with no difference by intervention arm. Transition from alcohol use to abstinence was associated with a decrease in liver enzymes, with a marginally greater decrease in the intervention group (p=0.05 for ALT; p=0.06 for AST). In multivariate Markov models, those who used marijuana transitioned from alcohol abstinence to consumption more rapidly than non-users (RR=3.11); those who were homeless transitioned more slowly to alcohol abstinence (RR=0.47); and those who had ever received a clinical diagnosis of liver disease transitioned more rapidly to abstinence (RR=1.88).

CONCLUSIONS

Although, behavioral counseling to reduce alcohol consumption among HCV-infected IDUs had a modest effect, reductions in alcohol consumption were associated with marked improvements in liver function. Interventions to reduce alcohol use among HCV-infected IDUs may benefit from being integrated into clinical care and monitoring of HCV infection.

Risk of window period HIV infection in high infectious risk donors: systematic review and meta-analysis

The OPTN defines high risk donors (HRDs), colloquially known as 'CDC high risk donors', as those thought to carry an increased risk of HIV window period (WP) infection prior to serologic detectability. However, the true risk of such infection remains unknown. To quantify the risk of WP infection in each HRD behavior category, we performed a systematic review and meta-analysis of studies of HIV prevalence and incidence. Of 3476 abstracts reviewed, 27 eligible studies of HIV infection in HRD populations were identified. Pooled HIV incidence estimates were calculated for each category of HRD behavior and used to calculate the risk of WP HIV infection. Risks ranged from 0.09-12.1 per 10 000 donors based on WP for ELISA and 0.04-4.9 based on nucleic acid testing (NAT), with NAT reducing WP risk by over 50% in each category. Injection drug users had the greatest risk of WP infection (4.9 per 10 000 donors by NAT WP), followed by men who have sex with men (4.2:10 000), commercial sex workers (2.7:10 000), incarcerated donors (0.9:10 000), donors exposed to HIV through blood (0.6:10 000), donors engaging in high-risk sex (0.3:10 000) and hemophiliacs (0.035:10 000). These estimates can help inform patient and provider decision making regarding HRDs.

Risk of window period hepatitis-C infection in high infectious risk donors: systematic review and meta-analysis

The OPTN classifies high infectious risk donors (HRDs) based on criteria originally intended to identify people at risk for HIV infection. These donors are sometimes referred to as 'CDC high risk donors' in reference to the CDC-published guidelines adopted by the OPTN. However, these guidelines are also being used to identify deceased donors at increased risk of window period (WP) hepatitis C virus (HCV) infection, although not designed for this purpose. The actual risk of WP HCV infection in HRDs is unknown. We performed a systematic review of 3476 abstracts and identified 37 eligible estimates of HCV incidence in HRD populations in the United States/Canada. Pooled HCV incidence was derived and used to estimate the risk of WP infection for each HRD category. Risks ranged from 0.26 to 300.6 per 10,000 donors based on WP for ELISA and 0.027 to 32.4 based on nucleic acid testing (NAT). Injection drug users were at highest risk (32.4 per 10,000 donors by NAT WP), followed by commercial sex workers and donors exhibiting high risk sexual behavior (12.3 per 10,000), men who have sex with men (3.5 per 10,000), incarcerated donors (0.8 per 10,000), donors exposed to HIV infected blood (0.4 per 10,000) and hemophiliacs (0.027 per 10,000). NAT reduced WP risk by approximately 10-fold in each category.

Hepatitis C virus antibody status, sociodemographic characteristics, and risk behaviour among injecting drug users in Croatia

The study was conducted among 76 injecting drug users (IDU) from seven Croatian cities during a three-year period (2005-2007). Each participant completed a questionnaire on sociodemographic characteristics and potential risk factors for hepatitis C virurs (HCV) infection followed by anti-HCV and anti-HIV antibody testing. The mean patient age was 30. The majority of patients (69.8%) reported more than one potential exposure to HCV: 97.1% had shared injecting equipment, 75% reported risk sexual behaviour, and 56.3% reported a history of travelling abroad. The overall HCV seroprevalence was 51.3% (95% CI = 40-63%). HCV seroprevalence increased with increasing number of risk behaviours (p = 0.026). Needle sharing frequency was the most important risk factor for hepatitis C. The HCV seroprevalence rate ranged from 27.3% in IDUs who answered that they shared needles occasionally to 100% in IDUs who always shared needles (p < 0.001). No other risk factors (age, gender, educational level, marital and employment status, history of travelling abroad and sexual risk behaviour) were associated with HCV seropositivity.

Drug and HIV-related risk behaviors after geographic migration among a cohort of injection drug users

To determine whether migration impacted on drug use and HIV-related risk behaviors among injection drug users (IDU), we identified participants in a prospective cohort of IDU (Vancouver Injection Drug User Study) who had reported migrating out of Greater Vancouver between May 1996 and November 2005. We compared risk behaviors before and after a move for individuals who migrated (movers) and for a similar period for non-movers using linear growth curve analyses. In total, 1,122 individuals were included, including 430 (38.3%) women and 331 (29.5%) Aboriginal participants. Among these, 192 (17.1%) individuals reported migrating out of Greater Vancouver between 1996 and 2005 while 930 (82.9%) did not. Movers were significantly younger than non-movers: 32.0 (Interquartile Range [IQR]: 24.3-39.2) and 34.6 (IQR: 26.9-40.8) respectively. A significant decrease in those reporting unstable housing, frequent heroin and cocaine injection occurred only in movers. Our findings suggest that, in this setting, risk-taking among IDU declines following periods of migration out of Greater Vancouver.

Longitudinal trajectories of ketamine use among young injection drug users

BACKGROUND

Ketamine is a dissociative anaesthetic that became increasingly popular in the club and rave scene in the 1980s and 1990s. Reports surfaced in the late 1990s indicating that ketamine was being injected in several U.S. cities by young injection drug users (IDUs). Since all studies on ketamine injection were cross-sectional, a longitudinal study was undertaken in 2005 to determine: characteristics of young IDUs who continue to inject ketamine; frequency of ketamine injection over an extended time period; risks associated with ongoing ketamine injection; and environmental factors that impact patterns of ketamine use.

METHODS

Young IDUs aged 16-29 with a history of injecting ketamine (n=101) were recruited from public locations in Los Angeles and followed during a 2-year longitudinal study. A semi-structured instrument captured quantitative and qualitative data on patterns of ketamine injection and other drug use. A statistical model sorted IDUs who completed three or more interviews (n=66) into three groups based upon patterns of ketamine injection at baseline and follow-up. Qualitative analysis focused on detailed case studies within each group.

RESULTS

IDUs recruited at baseline were typically in their early 20s, male, heterosexual, white, and homeless. Longitudinal injection trajectories included: "Moderates," who injected ketamine several times per year (n=5); "Occasionals," who injected ketamine approximately once per year (n=21); and "Abstainers," who did not inject any ketamine during follow-up (n=40). Findings suggest that ketamine is infrequently injected compared to other drugs such as heroin, cocaine, and methamphetamine. Most IDUs who begin injecting ketamine will stop or curb use due to: negative or ambivalent experiences associated with ketamine; an inability to find the drug due to declining supply; or maturing out of injecting drugs more generally.

CONCLUSION

Reducing ketamine injection among young IDUs may best be accomplished by targeting particular groups of IDUs identified in this study, such as homeless youth and homeless travellers.

Recruiting and retaining mobile young injection drug users in a longitudinal study

Longitudinal studies that research homeless persons or transient drug users face particular challenges in retaining subjects. Between 2005 and 2006, 101 mobile young injection drug users were recruited in Los Angeles into a 2-year longitudinal study. Several features of ethnographic methodology, including fieldwork and qualitative interviews, and modifications to the original design, such as toll-free calls routed directly to ethnographer cell phones and wiring incentive payments, resulted in retention of 78% of subjects for the first follow-up interview. Longitudinal studies that are flexible and based upon qualitative methodologies are more likely to retain mobile subjects while also uncovering emergent research findings.

Environmental conditions, political economy, and rates of injection drug use in large US metropolitan areas 1992-2002

City-specific studies have suggested the quality of the local environment and economic circumstances are associated with greater risk of injection drug use (IDU). No studies have assessed the relation among the quality of the local environment, economic circumstances, and IDU over time across US metropolitan areas. Annual numbers of IDUs in the 88 largest US metropolitan statistical areas (MSAs) were estimated by extrapolating, adjusting, and allocating existing estimates using various data sources. Generalized estimating equations were used to assess the relation among the quality of the local environment, metropolitan political economy, and IDU prevalence using lagged models taking into account potential confounders. MSAs with a worse local environment (measured as a one standard deviation difference) had a greater risk of IDU (relative risk [RR]=1.03, 95% confidence interval [CI]: 1.01, 1.06); similarly, a one-percentage point worsening of the political economy for an MSA was associated with greater risk of IDU (RR=1.04-1.10). Final models stratified by region indicated heterogeneity of effect by region whereby the quality of the local environment was associated with IDU strongest in the South (RR=1.12, CI: 1.05, 1.12) followed by the West (RR=1.04, CI: 1.01, 1.07) and Midwest (RR=1.03, CI: 1.00, 1.06), and the metropolitan political economy was associated with IDU in the West (RR=1.03-1.09) and Northeast (RR=1.04-1.12). Our results underscore the importance of sociopolitical factors as determinants of IDU in MSAs. Structural solutions targeted at improving environmental conditions and economic circumstances should be considered as drug use interventions.

Molecular and contextual markers of hepatitis C virus and drug abuse

The spread of hepatitis C virus (HCV) infection involves a complex interplay of social risks, and molecular factors of both virus and host. Injection drug abuse is the most powerful risk factor for HCV infection, followed by sexual transmission and additional non-injection drug abuse factors such as co-infection with other viruses and barriers to treatment. It is clearly important to understand the wider context in which the factors related to HCV infection occur. This understanding is required for a comprehensive approach leading to the successful prevention, diagnosis, and treatment of HCV. An additional consideration is that current treatments and advanced molecular methods are generally unavailable to socially disadvantaged patients. Thus, the recognition of behavioral/social, viral, and host factors as components of an integrated approach to HCV is important to help this vulnerable group. Equally important, this approach is key to the development of personalized patient treatment - a significant goal in global healthcare. In this review, we discuss recent findings concerning the impact of drug abuse, epidemiology, social behavior, virology, immunopathology, and genetics on HCV infection and the course of disease.

Towards an Explanation of Subjective Ketamine Experiences among Young Injection Drug Users

Ketamine is a dissociative anesthetic with powerful sedative and hallucinogenic properties. Despite the wide variability in reported subjective experiences, no study has attempted to describe the particular factors that shape these experiences. This manuscript is based upon a sample of 213 young injection drug users recruited in New York, New Orleans, and Los Angeles with histories of ketamine use. Qualitative interviews focused on specific ketamine events, such as first injection of ketamine, most recent injection of ketamine, and most recent experience sniffing ketamine. Findings indicate that six factors impacted both positive and negative ketamine experiences: polydrug use, drug using history, mode of administration, quantity and quality of ketamine, user group, and setting. Most subjective experiences during any given ketamine event were shaped by a combination of these factors. Additionally, subjective ketamine experiences were particularly influenced by a lifestyle characterized by homelessness and traveling.