HIV incidence among injection drug users in Baltimore, Maryland (1988-2004)

Using serial cross-sectional surveys to create a retrospective nested cohort to determine HIV incidence from 20 US cities

OBJECTIVE

To estimate HIV incidence using successive cross-sectional surveys by creating retrospective nested cohorts among MSM, people who inject drugs (PWID), and heterosexually active persons (HET).

DESIGN

Cohorts were created among participants who had at least one repeat observation across four surveillance cycles from National HIV Behavioral Surveillance in 20 US cities.

METHODS

Repeat participants were identified using a combination of date of birth, race/ethnicity, metropolitan statistical area, and gender. The analysis was limited to participants who tested negative for HIV at baseline and were assumed to be at risk between cycles. We calculated person-years at risk from the individual time between cycles and used the total number of seroconversions to estimate incidence and a Poisson distribution to approximate variance. Rate ratios were calculated using age, gender, race/ethnicity, and region.

RESULTS

From 2008 to 2019, successive surveys recaptured nested cohorts of 1747 MSM, 3708 PWID, and 1396 HET. We observed an incidence rate of 2.5 per 100 person-years [95% confidence interval (CI) 2.1-2.8) among MSM; 0.6 per 100 person-years (95% CI 0.5-0.7) among PWID; and 0.3 per 100 person-years (95% CI 0.1-0.4) among HET. HIV incidence was higher among younger MSM, black MSM (compared with white MSM), and PWID residing in the South and territories (compared with the Midwest).

CONCLUSION

These estimates are consistent with previously published incidence estimates from prospective cohort studies among these populations. Using repeat cross-sectional surveys to simulate a cohort, may serve as another strategy in estimating HIV incidence.

Predictors of chronic opioid therapy in Medicaid beneficiaries with HIV who initiated antiretroviral therapy

The factors associated with chronic opioid therapy (COT) in patients with HIV is understudied. Using Medicaid data (2002–2009), this retrospective cohort study examines COT in beneficiaries with HIV who initiated standard combination anti-retroviral therapy (cART). We used generalized estimating equations on logistic regression models with backward selection to identify significant predictors of COT initiation. COT was initiated among 1014 out of 9615 beneficiaries with HIV (male: 10.4%; female: 10.7%). Those with older age, any malignancy, Hepatitis C infection, back pain, arthritis, neuropathy pain, substance use disorder, polypharmacy, (use of) benzodiazepines, gabapentinoids, antidepressants, and prior opioid therapies were positively associated with COT. In sex-stratified analyses, multiple predictors were shared between male and female beneficiaries; however, chronic obstructive pulmonary disease, liver disease, any malignancy, and antipsychotic therapy were unique to female beneficiaries. Comorbidities and polypharmacy were important predictors of COT in Medicaid beneficiaries with HIV who initiated cART.

Implementation of Syringe Services Programs to Prevent Rapid Human Immunodeficiency Virus Transmission in Rural Counties in the United States: A Modeling Study

BACKGROUND

Syringe services programs (SSPs) are effective venues for delivering harm-reduction services to people who inject drugs (PWID). However, SSPs often face significant barriers to implementation, particularly in the absence of known human immunodeficiency virus (HIV) outbreaks.

METHODS

Using an agent-based model, we simulated HIV transmission in Scott County, Indiana, a rural county with a 1.7% prevalence of injection drug use. We compared outcomes arising in the absence of an SSP, in the presence of a pre-existing SSP, and with implementation of an SSP after the detection of an HIV outbreak among PWID over 5 years following the introduction of a single infection into the network.

RESULTS

In the absence of an SSP, the model predicted an average of 176 infections among PWID over 5 years or an incidence rate of 12.1/100 person-years. Proactive implementation averted 154 infections and decreased incidence by 90.3%. With reactive implementation beginning operations 10 months after the first infection, an SSP would prevent 107 infections and decrease incidence by 60.8%. Reductions in incidence were also observed among people who did not inject drugs.

CONCLUSIONS

Based on model predictions, proactive implementation of an SSP in Scott County had the potential to avert more HIV infections than reactive implementation after the detection of an outbreak. The predicted impact of reactive SSP implementation was highly dependent on timely implementation after detecting the earliest infections. Consequently, there is a need for expanded proactive SSP implementation in the context of enhanced monitoring of outbreak vulnerability in Scott County and similar rural contexts.

The association of α4β7 expression with HIV acquisition and disease progression in people who inject drugs and men who have sex with men: Case control studies

BACKGROUND

α4β7 is a gut-homing integrin heterodimer that can act as a non-essential binding molecule for HIV. A previous study in heterosexual African women found that individuals with higher proportions of α4β7 expressing CD4⁺ T cells were more likely to become infected with HIV, as well as present with faster disease progression. It is unknown if this phenomenon is also observed in men who have sex with men (MSM) or people who inject drugs (PWID).

METHODS

MSM and transgender women who seroconverted as part of the HVTN 505 HIV vaccine trial and PWID who seroconverted during the ALIVE cohort study were selected as cases and matched to HIV-uninfected controls from the same studies (1:1 and 1:3, respectively). Pre-seroconversion PBMC samples from cases and controls in both studies were examined by flow cytometry to measure levels of α4β7 expression on CD4⁺ T cells. Multivariable conditional logistic regression was used to compare α4β7 expression levels between cases and controls. A Kaplan-Meier curve was used to examine the association of α4β7 expression pre-seroconversion with HIV disease progression.

FINDINGS

In MSM and transgender women (n = 103 cases, 103 controls), there was no statistically significant difference in the levels of α4β7 expression on CD4⁺ T cells between cases and controls (adjusted odds ratio [adjOR] =1.10, 95% confidence interval [CI]=0.94,1.29; p = 0.246). Interestingly, in PWID (n = 49 cases, 143 controls), cases had significantly lower levels of α4β7 expression compared to their matched controls (adjOR = 0.80, 95% CI = 0.68, 0.93; p = 0.004). Among HIV-positive PWID (n = 47), there was no significant association in HIV disease progression in individuals above or below the median level of α4β7 expression (log-rank p = 0.84).

INTERPRETATION

In contrast to findings in heterosexual women, higher α4β7 expression does not predict HIV acquisition or disease progression in PWID or MSM.

FUNDING

This study was supported in part by the Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health. The study was also supported by extramural grants from NIAID T32AI102623 (E.U.P.), and UM1AI069470.

Receptive anal sex contributes substantially to heterosexually acquired HIV infections among at-risk women in twenty US cities: Results from a modelling analysis

PROBLEM

Receptive anal intercourse (RAI) is more efficient than receptive vaginal intercourse (RVI) at transmitting HIV, but its contribution to heterosexually acquired HIV infections among at-risk women in the USA is unclear.

METHOD OF STUDY

We analysed sexual behaviour data from surveys of 9152 low-income heterosexual women living in 20 cities with high rates of HIV conducted in 2010 and 2013 as part of US National HIV Behavioral Surveillance. We estimated RAI prevalence (past-year RAI) and RAI fraction (fraction of all sex acts (RVI and RAI) at the last sexual episode that were RAI among those reporting past-year RAI) overall and by key demographic characteristics. These results and HIV incidence were used to calibrate a risk equation model to estimate the population attributable fraction of new HIV infections due to RAI (PAF_RAI ) accounting for uncertainty in parameter assumptions.

RESULTS

Receptive anal intercourse prevalence (overall: 32%, city range: 19%-60%) and RAI fraction (overall: 27%, city range: 18%-34%) were high overall and across cities, and positively associated with exchange sex. RAI accounted for an estimated 41% (uncertainty range: 18%-55%) of new infections overall (city range: 21%-57%). Variability in PAF_RAI estimates was most influenced by uncertainty in the estimate of the per-act increased risk of RAI relative to RVI and the number of sex acts.

CONCLUSION

Receptive anal intercourse may contribute disproportionately to new heterosexually acquired HIV infections among at-risk low-income women in the USA, meaning that tools to prevent HIV transmission during RAI are warranted. The number of RVI and RAI acts should also be collected to monitor heterosexually acquired HIV infections.

Incarceration history and risk of HIV and hepatitis C virus acquisition among people who inject drugs: a systematic review and meta-analysis

BACKGROUND

People who inject drugs (PWID) experience a high prevalence of incarceration and might be at high risk of HIV and hepatitis C virus (HCV) infection during or after incarceration. We aimed to assess whether incarceration history elevates HIV or HCV acquisition risk among PWID.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, Embase, and PsycINFO databases for studies in any language published from Jan 1, 2000 until June 13, 2017 assessing HIV or HCV incidence among PWID. We included studies that measured HIV or HCV incidence among community-recruited PWID. We included only studies reporting original results and excluded studies that evaluated incident infections by self-report. We contacted authors of cohort studies that met the inclusion or exclusion criteria, but that did not report on the outcomes of interest, to request data. We extracted and pooled data from the included studies using random-effects meta-analyses to quantify the associations between recent (past 3, 6, or 12 months or since last follow-up) or past incarceration and HIV or HCV acquisition (primary infection or reinfection) risk among PWID. We assessed the risk of bias of included studies using the Newcastle-Ottawa Scale. Between-study heterogeneity was evaluated using the I2 statistic and the P-value for heterogeneity.

FINDINGS

We included published results from 20 studies and unpublished results from 21 studies. These studies originated from Australasia, western and eastern Europe, North and Latin America, and east and southeast Asia. Recent incarceration was associated with an 81% (relative risk [RR] 1·81, 95% CI 1·40-2·34) increase in HIV acquisition risk, with moderate heterogeneity between studies (I2=63·5%; p=0·001), and a 62% (RR 1·62, 95% CI 1·28-2·05) increase in HCV acquisition risk, also with moderate heterogeneity between studies (I2=57·3%; p=0·002). Past incarceration was associated with a 25% increase in HIV (RR 1·25, 95% CI 0·94-1·65) and a 21% increase in HCV (1·21, 1·02-1·43) acquisition risk.

INTERPRETATION

Incarceration is associated with substantial short-term increases in HIV and HCV acquisition risk among PWID and could be a significant driver of HCV and HIV transmission among PWID. These findings support the need for developing novel interventions to minimise the risk of HCV and HIV acquisition, including addressing structural risks associated with drug laws and excessive incarceration of PWID.

FUNDING

Engineering and Physical Sciences Research Council, National Institute for Health Research, National Institutes of Health.

A Cohort Approach to Real-Time Detection of Acute HIV Infections Among People Who Inject Drugs in St. Petersburg, Russia

To detect acute HIV infections (AHIs) in real time among people who inject drugs (PWID) in St. Petersburg, Russia and to test the feasibility of this approach. Prospective cohort study. One hundred seronegative or acutely HIV-infected at screening PWID were enrolled and followed until the end of the 12-month pilot period. Each participant was evaluated, tested, and counseled for HIV monthly. Two HIV tests were used: HIV antibody and HIV RNA PCR. If diagnosed with AHI, participants were followed weekly for a month; then, monthly for 3 months; and then, quarterly for the duration of the follow-up period. HIV risk behavior was assessed at each study visit. Most enrolled PWID were 30-39 years old, male, completed high school or more, not employed full-time, heroin users, and frequently shared injection paraphernalia. AHI prevalence at screening was 1.8% [95% confidence interval (CI): 0.4, 5.5]. Three participants with AHI at enrollment represented 3% (95% CI: 0.6, 8.5) of the 100 participants who consented to enroll. Among the HIV-uninfected participants (n = 97), the AHI incidence over time was 9.3 per 100 person-years. Persons with AHI were more likely to report alcohol intoxication within the prior 30 days. This was the first study to detect AHI using a cohort approach. The approach proved to be feasible: recruitment, retention, AHI detection, and virological endpoints were successfully reached. A cost analysis in a real-world setting would be required to determine if this strategy could be brought to scale. The study revealed continued high HIV incidence rate among PWID in St. Petersburg, Russia and the importance of prevention and treatment programs for this group.

Rapid Decline in HIV Incidence Among Persons Who Inject Drugs During a Fast-Track Combination Prevention Program After an HIV Outbreak in Athens

Background

A "seek-test-treat" intervention (ARISTOTLE) was implemented in response to an outbreak of human immunodeficiency virus (HIV) infection among persons who inject drugs (PWID) in Athens. We assess trends in HIV incidence, prevalence, risk behaviors and access to prevention/treatment.

Methods

Methods included behavioral data collection, provision of injection equipment, HIV testing, linkage to opioid substitution treatment (OST) programs and HIV care during 5 rounds of respondent-driven sampling (2012-2013). HIV incidence was estimated from observed seroconversions.

Results

Estimated coverage of the target population was 88% (71%-100%; 7113 questionnaires/blood samples from 3320 PWID). The prevalence of HIV infection was 16.5%. The incidence per 100 person-years decreased from 7.8 (95% confidence interval, 4.6-13.1) (2012) to 1.7 (0.55-5.31) (2013; P for trend = .001). Risk factors for seroconversion were frequency of injection, homelessness, and history of imprisonment. Injection at least once daily declined from 45.2% to 18.8% (P < .001) and from 36.8% to 26.0% (P = .007) for sharing syringes, and the proportion of undiagnosed HIV infection declined from 84.3% to 15.0% (P < .001). Current OST increased from 12.2% to 27.7% (P < .001), and 48.4% of unlinked seropositive participants were linked to HIV care through 2013. Repeat participants reported higher rates of adequate syringe coverage, linkage to HIV care and OST.

Conclusions

Multiple evidence-based interventions delivered through rapid recruitment in a large proportion of the population of PWID are likely to have helped mitigate this HIV outbreak.

Drug use and its associated factors among money boys in Hunan Province, China

OBJECTIVES

To describe drug use, types of drugs and related factors among money boys in Hunan Province, China.

STUDY DESIGN

A cross-sectional study was conducted between July 2012 and January 2013.

METHODS

Based on respondent-driven sampling, researchers located seven 'seeds' via a gay-dating website: http://www.ixxqy.org. After three waves of recruitment, 234 money boys were enrolled. They were asked to complete a 23-item questionnaire regarding demographic characteristics, drug use, a history of human immunodeficiency virus infection and family environment. Descriptive statistics and logistic regression analysis were conducted using Statistical Package for the Social Sciences Version 20.0.

RESULTS

In total, 205 valid questionnaires were collected. Based on the data collected, 80 (39.0%) money boys had used drugs within the last 3 months. Rush popper (36.6%) and methamphetamine (12.7%) were used most commonly, and other drugs used were ecstasy (7.8%), ketamine (5.9%), marijuana (2.4%), morphine (1.5%), heroin (1.0%) and cocaine (0.5%). Factors included in the logistic regression were length of service (odds ratio [OR] 0.395, 95% confidence interval [CI] 0.175-0.896), being an only child (OR 2.272, 95% CI 1.108-4.659), relationship between parents (OR 0.428, 95% CI 0.213-0.858) and social network (OR 2.387, 95% CI 1.144-4.970). A shorter length of service and a good relationship between parents were protective factors against drug use, while being an only child and having a wide social network were risk factors.

CONCLUSION

Drug use is common among money boys. This study found that length of service, being an only child, relationship between parents and social network are associated with drug use.

Prevention and treatment produced large decreases in HIV incidence in a model of people who inject drugs

In the United States, people who inject drugs continue to be at greatly increased risk of HIV infection. To estimate the effectiveness of various prevention scenarios, we modeled HIV transmission in a dynamic network of drug users and people who did not use drugs that was based on the New York Metropolitan Statistical Area population. We compared the projected HIV incidence in 2020 and 2040 if current approaches continue to be used to the incidence if one or more of the following hypothetical interventions were applied: increased HIV testing, improved access to substance abuse treatment, increased use of needle and syringe programs, scaled-up treatment as prevention, and a "high impact" combination scenario, consisting of all of the strategies listed above. No strategy completely eliminated HIV transmission. The high-impact combination strategy produced the largest decrease in HIV incidence-a 62 percent reduction compared to the status quo. Our results suggest that increased resources for and investments in multiple HIV prevention approaches will be required to eliminate HIV transmission among people who inject drugs.

HIV infection among persons who inject drugs: ending old epidemics and addressing new outbreaks

AIDS among persons who inject drugs, first identified in December 1981, has become a global epidemic. Injecting drug use has been reported in 148 countries and HIV infection has been seen among persons who inject drugs in 61 countries. Many locations have experienced outbreaks of HIV infection among persons who inject drugs, under specific conditions that promote very rapid spread of the virus. In response to these HIV outbreaks, specific interventions for persons who inject drugs include needle/syringe exchange programs, medicated-assisted treatment (with methadone or buprenorphine) and antiretroviral therapy. Through a 'combined prevention' approach, these interventions significantly reduced new HIV infections among persons who inject drugs in several locations including New York City, Vancouver and France. The efforts effectively ended the HIV epidemic among persons who inject drugs in those locations. This review examines possible processes through which combined prevention programs may lead to ending HIV epidemics. However, notable outbreaks of HIV among persons who inject drugs have recently occurred in several countries, including in Athens, Greece; Tel-Aviv, Israel; Dublin, Ireland; as well as in Scott County, Indiana, USA. This review also considers different factors that may have led to these outbreaks. We conclude with addressing the remaining challenges for reducing HIV infection among persons who inject drugs.

Trends in Injection Drug Use Among High School Students, U.S., 1995-2013

INTRODUCTION

Injection drug use is the most frequently reported risk behavior among new cases of hepatitis C virus infection, and recent reports of increases in infection are of great concern in many communities. This study assessed the prevalence and trends in injection drug use among U.S. high school students.

METHODS

Data were from CDC's Youth Risk Behavior Surveillance System, which collects information on health risk behaviors at the national, state, and large urban school district levels. Analyses were conducted in 2014.

RESULTS

In 2013, 1.7% of high school students nationwide had ever injected any illegal drug. Nationwide, ever injecting any illegal drug did not change significantly from 1995 to 2013, except among black non-Hispanic students. For this subgroup, both a significant linear increase from 1995 to 2013 and a significant quadratic trend were observed, with injection drug use increasing from 1995 to 2009 and decreasing from 2009 to 2013. Significant linear increases in injection drug use occurred in five states (Arkansas, Hawaii, Maine, Maryland, and New York) and six large urban school districts (Baltimore, Memphis, Miami-Dade County, New York City, Philadelphia, and Seattle). Significant linear decreases occurred in three states (Massachusetts, South Dakota, and West Virginia). Both a significant linear increase and quadratic trend were observed in Maine; quadratic trends were observed in Tennessee, Utah, and Palm Beach County, Florida.

CONCLUSIONS

In some geographic areas and population groups, an increasing or high frequency of injection drug use was found among high school students, who should be targeted for prevention.

Reduction in Needle Sharing Among Seattle-Area Injection Drug Users Across 4 Surveys, 1994-2013

OBJECTIVES

We evaluated time trends in sharing needles and other injection equipment from 1994 to 2013 among injection drug users in the Seattle, Washington area.

METHODS

We combined data from 4 sources: the Risk Activity Variables, Epidemiology, and Network (RAVEN) study, recruited from institutional settings; the Kiwi study, recruited from jails; National HIV Behavioral Surveillance system (NHBS) surveys, which used respondent-driven sampling; and surveys at needle-exchange sites.

RESULTS

Levels of needle sharing were higher in the earlier studies: RAVEN, 1994 to 1997 (43%) and Kiwi, 1998 to 2002 (61%). In the NHBS surveys, the initial level of 44% in 2005 declined to 31% in the period 2009 to 2012. Across needle-exchange surveys (2009-2013) the level was 21%. There was a parallel reduction in sharing other injection equipment. These trends persisted after control for sociodemographic and risk-associated variables. There was a contemporaneous increase in the number of needles distributed by local needle exchanges and a decline in the number of reported HIV cases among injection drug users.

CONCLUSIONS

The apparent long-term reduction in sharing injection equipment suggests substantial success in public health efforts to reduce the sharing of injection equipment.

The influence of a peer-based HIV prevention intervention on conversation about HIV prevention among people who inject drugs in Baltimore, Maryland

STEP into Action assessed the efficacy of a peer-based HIV prevention intervention in reducing HIV risk behaviors among people who inject drugs (PWIDs) in Baltimore. This analysis examined the effect of the intervention on the change in frequency of conversation about HIV prevention topics over time. 114 participants were randomized into an experimental and 113 into a control group. Data was collected prospectively at 6, 12, and 18 months. The experimental group talked more frequently about HIV prevention topics compared to the control group at 6-month visit. At 18 months relative risk ratios (RRR) remained statistically significant for conversation about the danger of needle sharing (RRR = 3.21) and condom use (RRR = 2.81). The intervention resulted in an increased conversation about HIV prevention among PWIDs, but the sustainability past 6 months remained a challenge; suggesting that interventions should be designed to constantly reinforce communication about HIV prevention among PWIDs.

Social place as a location of potential core transmitters-implications for the targeted control of sexually transmitted disease transmission in urban areas

PURPOSE

Places are an important determinant of risk for sexually transmitted infection (STI) acquisition and transmission. We sought to identify social places that are critical for targeted STI control activities. The objective of this study was to determine whether sex partner meeting places characterized by drug markets, sex markets, and separately, drug and/or sex markets were more likely to have potential core transmitters as compared with other sex partner meeting places in one urban setting.

METHODS

In 2008-2009, heterosexual sex partner places or venues were identified in Baltimore, MD using a venue-based study approach.

RESULTS

A total of 1334 participants aged 18 to 35 years were enrolled at 85 venues. In those participants, 39 potential core transmitters were identified and 31% of venues had at least one potential core transmitter. In final age-adjusted and gender-adjusted models, core transmitters were significantly more likely to be identified at drug markets (OR = 1.37; 95% CI = 1.23-1.53), sex markets (OR = 1.27; 95% CI = 1.14-1.41), and drug and/or sex markets (OR = 1.49; 95% CI = 1.32-1.68).

CONCLUSIONS

This study identified key characteristics of venues, such as drug and sex market activity, that may be important in identifying places for the targeted control of STI transmission.

Police Encounters Among Needle Exchange Clients in Baltimore: Drug Law Enforcement as a Structural Determinant of Health

OBJECTIVES

We piloted a monitoring mechanism to document police encounters around programs targeting people who inject drugs (PWID), and assessed their demographic predictors at 2 Baltimore, Maryland, needle exchange program (NEP) sites.

METHODS

In a brief survey, 308 clients quantified, characterized, and sited recent police encounters. Multivariate linear regression determined encounter predictors, and we used geocoordinate maps to illustrate clusters.

RESULTS

Within the past 6 months, clients reported a median of 3 stops near NEP sites (interquartile range [IQR] = 0-7.5) and a median of 1 arrest in any location (IQR = 0-2). Three respondents reported police referral to the NEP. Being younger (P = .009), being male (P = .033), and making frequent NEP visits (P = .02) were associated with reported police stops. Among clients reporting arrest or citation for syringe possession, Whites were significantly less likely than non-Whites to report being en route to or from an NEP (P < .001). Reported encounters were clustered around NEPs.

CONCLUSIONS

Systematic surveillance of structural determinants of health for PWID proved feasible when integrated into service activities. Improved monitoring is critical to informing interventions to align policing with public health, especially among groups subject to disproportionate levels of drug law enforcement.

Utilizing mHealth methods to identify patterns of high risk illicit drug use

INTRODUCTION

We assessed patterns of illicit drug use using mobile health (mHealth) methods and subsequent health care indicators among drug users in Baltimore, MD.

METHODS

Participants of the EXposure Assessment in Current Time (EXACT) study were provided a mobile device for assessment of their daily drug use (heroin, cocaine or both), mood and social context for 30 days from November 2008 through May 2013. Real-time, self-reported drug use events were summed for individuals by day. Drug use risk was assessed through growth mixture modeling. Latent class regression examined the association of mHealth-defined risk groups with indicators of healthcare access and utilization.

RESULTS

109 participants were a median of 48.5 years old, 90% African American, 52% male and 59% HIV-infected. Growth mixture modeling identified three distinct classes: low intensity drug use (25%), moderate intensity drug use (65%) and high intensity drug use (10%). Compared to low intensity drug users, high intensity users were younger, injected greater than once per day, and shared needles. At the subsequent study visit, high intensity drug users were nine times less likely to be medically insured (adjusted OR: 0.10, 95%CI: 0.01-0.88) and at greater risk for failing to attend any outpatient appointments (aOR: 0.13, 95%CI: 0.02-0.85) relative to low intensity drug users.

CONCLUSIONS

Real-time assessment of drug use and novel methods of describing sub-classes of drug users uncovered individuals with higher-risk behavior who were poorly utilizing healthcare services. mHealth holds promise for identifying individuals engaging in high-risk behaviors and delivering real-time interventions to improve care outcomes.

Identifying and characterizing places for the targeted control of heterosexual HIV transmission in urban areas

Places with active HIV transmission may serve as key locations for targeted control. In 2008-2009, heterosexual sex partner venues in Baltimore, MD were identified using a three-phase process and characterized by the presence or absence of HIV cases. 1,594 participants aged 18-35 years were enrolled at 87 venues. The study yielded an overall HIV prevalence of 3.7 %; 42 % of venues had ≥1 case of HIV (i.e., HIV positive venues). In final age-adjusted models, HIV positive venues had 10 % more high HIV-risk sexual partnering (95 % CI 1.01, 1.19) and more than twice as much drug market activity (95 % CI 1.04, 6.46) compared to HIV negative venues. Commercial sex work, parenteral risk behavior and venue-level sex market activity were not significantly associated with HIV status of the venues. This study highlights characteristics of venues, such as drug market activity, that may be important in identifying places with active HIV transmission.

The association between neighborhood residential rehabilitation and injection drug use in Baltimore, Maryland, 2000-2011

This study utilized multilevel cross-classified models to longitudinally assess the association between neighborhood residential rehabilitation and injection drug use. We also assessed whether relocating between neighborhoods of varying levels of residential rehabilitation was associated with injection drug use. Residential rehabilitation was categorized into three groups (e.g. low, moderate, high), and lagged one visit to ensure temporality. After adjusting for neighborhood and individual-level factors, residence in a neighborhood with moderate residential rehabilitation was associated with a 23% reduction in injection drug use [AOR=0.77; 95% CI (0.67,0.87)]; residence in a neighborhood with high residential rehabilitation was associated with a 26% reduction in injection drug use [AOR=0.74; 95% CI (0.61,0.91)]. Continuous residence within neighborhoods with moderate/high rehabilitation, and relocating to neighborhoods with moderate/high rehabilitation, were associated with a lower likelihood of injection drug use. Additional studies are needed to understand the mechanisms behind these relationships.

Extremely low and sustained HIV incidence among people who inject drugs in a setting of harm reduction

This study created a retrospective cohort by linking repeat respondents in a large, national, annual cross-sectional sero-survey to estimate HIV incidence among people who inject drugs (PWID) in Australia. The results indicate extremely low and sustained rates of HIV incidence (0.11 per 100 person-years) over almost two decades (1995-2012). The findings demonstrate that sustained prevention of HIV transmission among PWID is possible and suggest that the early establishment and rapid scale-up of needle and syringe programmes, at a time when background prevalence was low, likely contributed to the prevention of an HIV epidemic among Australian PWID.

The longitudinal association between homelessness, injection drug use, and injection-related risk behavior among persons with a history of injection drug use in Baltimore, MD

BACKGROUND

Few studies have assessed the temporal association between homelessness and injection drug use, and injection-related risk behavior.

METHODS

Among a cohort of 1405 current and former injection drug users in follow-up from 2005 to 2009, we used random intercept models to assess the temporal association between homelessness and subsequent injection drug use, and to determine whether the association between homelessness and sustained injection drug use among active injectors differed from the association between homelessness and relapse among those who stopped injecting. We also assessed the association between homelessness and subsequent injection-related risk behavior among participants who injected drugs consecutively across two visits. Homelessness was categorized by duration: none, <1 month, and ≥1 month.

RESULTS

Homelessness was reported on at least one occasion by 532 (38%) participants. The relationship between homelessness and subsequent injection drug use was different for active injectors and those who stopped injecting. Among those who stopped injecting, homelessness was associated with relapse [<1 month: AOR=1.67, 95% CI (1.01, 2.74); ≥1 month: AOR=1.34 95% CI (0.77, 2.33)]. Among active injectors, homelessness was not associated with sustained injection drug use [<1 month: AOR=1.03, 95% CI (0.71, 1.49); ≥1 month: AOR=0.81 95% CI (0.56, 1.17)]. Among those injecting drugs across two consecutive visits, homelessness ≥1 month was associated with subsequent injection-related risk behavior [AOR=1.61, 95% CI (1.06, 2.45)].

CONCLUSION

Homelessness appears to be associated with relapse and injection-related risk behavior. Strengthening policies and interventions that prevent homelessness may reduce injection drug use and injection-related risk behaviors.

HIV prevalence overall and among high-HIV-risk behaviorally defined subgroups among heterosexuals at community-based venues in a Mid-Atlantic, US City

A clear understanding of local transmission dynamics is a prerequisite for the design and implementation of successful HIV prevention programs. There is a tremendous need for such programs geared towards young African-American women living in American cities with syndemic HIV and injection drug use. In some of these American cities, including Baltimore, the HIV prevalence rate among young African-American women is comparable to that in some African nations. High-risk heterosexual sex, i.e., sex with an injection drug user or sex with someone known to have HIV, is the leading risk factor for these young women. Characterizing transmission dynamics among heterosexuals has been hampered by difficulty in identifying HIV cases in these settings. The case identification method described in this paper was designed to address challenges encountered by previous researchers, was based on the Priorities for Local AIDS Cases methodology, and was intended to identify a high number of HIV cases rather than achieve a representative sample (Weir et al., Sex Transm Infect 80(Suppl 2):ii63-8, 2004. Through a three-phase process, 87 venues characterized as heterosexual sex partner meeting sites were selected for participant recruitment in Baltimore, MD. One thousand six hundred forty-one participants were then recruited at these 87 venues, administered a behavioral risk questionnaire, and tested for HIV. The HIV prevalence was 3 % overall, 3 % among males, and 4 % among females and ranged from 1.7 to 22.6 % among high-HIV-risk subgroups. These findings indicate that attributing HIV transmission to high-risk heterosexual sex vs. other high-HIV-risk behaviors would be difficult. Moving beyond individual risk profiles to characterize the risk profile of venues visited by heterosexuals at high risk of HIV acquisition may reveal targets for HIV transmission prevention and should be the focus of future investigations.

The spatial and temporal association of neighborhood drug markets and rates of sexually transmitted infections in an urban setting

This study examined temporal and spatial relationships between neighborhood drug markets and gonorrhea among census block groups from 2002 to 2005. This was a spatial, longitudinal ecologic study. Poisson regression was used with adjustment in final models for socioeconomic status, residential stability and vacant housing. Increased drug market arrests were significantly associated with a 11% increase gonorrhea (adjusted relative risk (ARR) 1.11; 95% CI 1.05, 1.16). Increased drug market arrests in adjacent neighborhoods were significantly associated with a 27% increase in gonorrhea (ARR 1.27; 95% CI 1.16, 1.36), independent of focal neighborhood drug markets. Increased drug market arrests in the previous year in focal neighborhoods were not associated with gonorrhea (ARR 1.04; 95% CI 0.98, 1.10), adjusting for focal and adjacent drug markets. While the temporal was not supported, our findings support an associative link between drug markets and gonorrhea. The findings suggest that drug markets and their associated sexual networks may extend beyond local neighborhood boundaries indicating the importance of including spatial lags in regression models investigating these associations.

Analysis of duration of risk behaviour for key populations: a literature review

Background

The objective of this paper is to review literature in order to calculate regional estimates of the average duration of time individuals maintain a specific high-risk behaviour.

Methods

The review targeted the key populations of female sex workers (FSW), male clients of female sex workers (MCFSW), people who inject drugs (injecting drug users (IDU)) and high-risk men who have sex with men (MSM). To be included in the review the study had to provide information on (1) the time a person spent at risk until death or cessation of the risk behaviour, (2) the percentage of the sample who initiated the risk behaviour in less than a year or (3) the mean or median duration of the behaviour from a representative sample.

Results

49 papers were found for the FSW population describing the period of time FSW stay in sex work to be between 2.9 years (Asia) and 12 years (Latin America). Eight papers were found for MCFSW showing the duration of the risk behaviour in this category varying from 4.6 years in Africa to 32 years in Asia. 86 papers were reviewed for the population of IDU showing that the average time a person injects illegal drugs varies from 5.6 years (Africa) to 21 years (South America). No information was found for duration of high-risk behaviour among MSM; instead, the definitions found in the literature for high- and low-risk behaviour among MSM were described.

Conclusions

There is high variability of estimates of duration of high-risk behaviours at regional level. More research is needed to inform models and prevention programmes on the average duration of time individuals maintain a specific high-risk behaviour.

Estimating the effects of multiple time-varying exposures using joint marginal structural models: alcohol consumption, injection drug use, and HIV acquisition

The joint effects of multiple exposures on an outcome are frequently of interest in epidemiologic research. In 2001, Hernán et al (J Am Stat Assoc. 2001;96:440-448) presented methods for estimating the joint effects of multiple time-varying exposures subject to time-varying confounding affected by prior exposure using joint marginal structural models. Nonetheless, the use of these joint models is rare in the applied literature. Minimal uptake of these joint models, in contrast to the now widely used standard marginal structural model, is due in part to a lack of examples demonstrating the method. In this paper, we review the assumptions necessary for unbiased estimation of joint effects as well as the distinction between interaction and effect measure modification. We demonstrate the use of marginal structural models for estimating the joint effects of alcohol consumption and injection drug use on HIV acquisition, using data from 1525 injection drug users in the AIDS Link to Intravenous Experience cohort study. In the joint model, the hazard ratio (HR) for heavy drinking in the absence of any drug injections was 1.58 (95% confidence interval = 0.67-3.73). The HR for any drug injections in the absence of heavy drinking was 1.78 (1.10-2.89). The HR for heavy drinking and any drug injections was 2.45 (1.45-4.12). The P values for multiplicative and additive interaction were 0.7620 and 0.9200, respectively, indicating a lack of departure from effects that multiply or add. We could not rule out interaction on either scale due to imprecision.

Neighborhood drug markets: a risk environment for bacterial sexually transmitted infections among urban youth

We hypothesized that neighborhoods with drug markets, as compared to those without, have a greater concentration of infected sex partners, i.e. core transmitters, and that in these areas, there is an increased risk environment for STIs. This study determined if neighborhood drug markets were associated with a high-risk sex partnership and, separately, with a current bacterial STI (chlamydia and/or gonorrhea) after controlling for individual demographic and sexual risk factors among a household sample of young people in Baltimore City, MD. Analyses also tested whether links were independent of neighborhood socioeconomic status. Data for this study were collected from a household study, systematic social observations and police arrest, public health STI surveillance and U.S. census data. Nonlinear multilevel models showed that living in neighborhoods with household survey-reported drug markets increased the likelihood of having a high-risk sex partnership after controlling for individual-level demographic factors and illicit drug use and neighborhood socioeconomic status. Further, living in neighborhoods with survey-reported drug markets increased the likelihood of having a current bacterial STI after controlling for individual-level demographic and sexual risk factors and neighborhood socioeconomic status. The results suggest that local conditions in neighborhoods with drug markets may play an important role in setting-up risk environments for high-risk sex partnerships and bacterial STIs. Patterns observed appeared dependent on the type of drug market indicator used. Future studies should explore how conditions in areas with local drug markets may alter sexual networks structures and whether specific types of drug markets are particularly important in determining STI risk.

Use of North America's first medically supervised safer injecting facility among HIV-positive injection drug users

The objective of this study was to examine supervised injecting facility (SIF) use among a cohort of 395 HIV-positive injection drug users (IDUs) in Vancouver, Canada. The correlates of SIF use were identified using generalized estimating equation analyses. In multivariate analyses, frequent SIF use was associated with homelessness (adjusted odds ratio [AOR] = 1.90), daily heroin injection (AOR = 1.56), and daily cocaine injection (AOR = 1.59). The reasons given for not using the SIF included a preference for injecting at home and already having a safe place to inject. The SIF services most commonly used were needle exchange and nursing services. The SIF appears to have attracted a high-risk subpopulation of HIV-positive IDUs; this coverage perhaps could be extended with the addition of HIV-specific services such as disease monitoring and the provision of antiretroviral therapy.

Temporal changes in risk factors associated with HIV seroconversion among injection drug users in eastern central Canada

OBJECTIVES

To investigate temporal trends in HIV incidence rates and to assess changes over time in associated risk factors.

METHODS

Since 1995, the SurvUDI network has conducted surveillance among IDUs recruited in harm reduction programmes in eastern central Canada. Among the 11,731 participants, 2903 repeaters were initially HIV-negative. HIV incidence was calculated and compared for two time periods (1995-2002 vs. 2003-2009). Multivariate Cox proportional hazard models with time-dependent covariates were used to assess risk factors associated with HIV seroconversion. Interactions between covariates and time periods were examined.

RESULTS

The overall HIV incidence rate was 2.7 per 100 person-years [95% confidence interval (CI) 2.4-3.1]. It significantly decreased from 3.1 per 100 person-years in 1995-2002 to 2.2 person-years in 2003-2009. Sex, needle borrowing, and cocaine as most often injected drug were independent and stable determinants of HIV seroconversion. Age, daily injection, sex work and being recruited in an urban area showed significant interactions with time. Being aged 25 years and older, injecting daily and being recruited in an urban area predicted HIV incidence in 1995-2002 but were no longer risk factors in 2003-2009. HIV incidence increased significantly among younger IDUs and sex work emerged as a new determinant of HIV incidence in 2003-2009.

CONCLUSION

HIV incidence has decreased over time but remains high among IDUs in eastern central Canada. Associations between risk factors and HIV incidence have changed. Further research is needed to better understand HIV transmission among younger IDUs and IDU sex workers.

Correlates of risky injection practices among past-year injection drug users among the US general population

BACKGROUND

With an estimated 1 million active injection drug users (IDUs), injection drug use continues to be a public health concern in the United States. Risky injection practices have been associated with the transmission of HIV, Hepatitis B and C, as well as other skin and soft tissue infections.

METHODS

We used data from 463 respondents, aged 18 and older, who were past-year IDUs in the 2005-2008 National Survey of Drug Use and Health (NSDUH). We investigated correlates of risky injection behavior among these recent IDUs.

RESULTS

Older age (≥ 35 versus 18-25) was associated with reusing one's own needle at last injection (aOR=1.80 [1.02-3.17], as were past year heroin (aOR=2.59 [1.18-5.66]) and cocaine injection (aOR=2.17 [1.13-4.15]). Past year crack cocaine use was positively associated with not cleaning needles with bleach (aOR=2.18 [1.10-4.33]). Past year cocaine injection was associated with obtaining needles in a risky manner (aOR=2.29 [1.23-4.25]). Methamphetamine injection was associated with obtaining needles in less risky ways (aOR=0.41 [0.20-0.84]).

CONCLUSION

Our findings indicate that some IDUs are continuing to engage in high risk injection behaviors. The identification of potential at-risk populations of IDUs may have implications for harm reduction interventions and HIV prevention programs.

Trends in human immunodeficiency virus incidence and risk behavior among injection drug users in montreal, Canada: a 16-year longitudinal study

The authors sought to investigate trends in the incidence of human immunodeficiency virus (HIV) infection, evaluate changes in risk behavior, and assess associations between syringe access programs and HIV seroconversion among injection drug users (IDUs) in Montreal, Canada, who were recruited and followed for a prospective cohort study between 1992 and 2008. Methods included Kaplan-Meier survival analysis and time-varying Cox regression models. Of 2,137 HIV-seronegative IDUs at enrollment, 148 became HIV-positive within 4 years (incidence: 3.3 cases/100 person-years; 95% confidence interval: 2.8, 3.9). An annual HIV incidence decline of 0.06 cases/100 person-years prior to 2000 was followed by a more rapid annual decline of 0.24 cases/100 person-years during and after 2000. Behavioral trends included increasing cocaine and heroin use and decreasing proportions of IDUs reporting any syringe-sharing or sharing a syringe with an HIV-positive person. In multivariate analyses, HIV seroconversion was associated with male gender, unstable housing, intravenous cocaine use, and sharing syringes or having sex with an HIV-positive partner. Always acquiring syringes from safe sources conferred a reduced risk of HIV acquisition among participants recruited after 2004, but this association was not statistically significant for participants recruited earlier. In conclusion, HIV incidence has declined in this cohort, with an acceleration of the reduction in HIV transmission after 2000.

Progress in HIV reduction and prevention among injection and noninjection drug users

Substantial progress has been made in reducing HIV among injection drug users (IDUs) in the United States, despite political and social resistance that reduced resources and restricted access to services. The record for HIV prevention among noninjecting drug users is less developed, although they are more numerous than IDUs. Newer treatments for opiate and alcohol abuse can now be integrated into primary HIV care; treatment for stimulant abuse is less developed. All drug users present challenges for newer HIV prevention strategies (eg, "test and treat," nonoccupational postexposure prophylaxis and preexposure prophylaxis, contingency management, and conditional cash transfer). A comprehensive HIV prevention program that includes multicomponent multilevel approaches (ie, individual, network, structural) has been effective in HIV prevention among IDUs. Expanding these approaches to noninjecting drug users, especially those at highest risk (eg, minority men who have sex with men) and incorporating these newer approaches is a public health priority.

Risks associated with crack cocaine smoking among exotic dancers in Baltimore, MD

BACKGROUND

There is a dearth of research focusing on sex work in exotic dance clubs. We conducted a cross-sectional study to examine the prevalence and correlates of crack cocaine smoking among a sample of exotic dancers.

METHODS

The "block," a historical red-light district in downtown Baltimore, MD, is comprised of 30 adult-entertainment establishments. Between 01/09 and 08/09, we conducted a survey with exotic dancers (N=98). The survey explored demographic, and drug and sexual/drug risk behaviors. Bivariate and multivariate analysis was conducted using Poisson regression with robust variance estimates to examine correlates of current crack smoking.

RESULTS

Crack cocaine smokers compared to non-crack cocaine smokers were significantly more likely to report: older age (29 vs. 23 years, respectively, p<0.0001); being White (79% vs. 50%, respectively, p=0.008); having been arrested (93% vs. 67%, respectively, p=0.008); daily alcohol consumption (36% vs. 17%, p=0.047); current heroin injection (57% vs. 13%, p<0.001); and current sex exchange (79% vs. 30%, p<0.001). In the presence of other variables, crack cocaine smokers compared to non-crack cocaine smokers were significantly older, more likely to report current heroin injection, and more likely to report current sex exchange.

DISCUSSION

We found high levels of drug use and sexual risk behaviors as well as a number of risks behaviors associated with crack cocaine smoking among this very under-studied population. Targeted interventions are greatly needed.

Trajectories of injection drug use over 20 years (1988-2008) in Baltimore, Maryland

The objective of this study was to identify longitudinal patterns of injection drug use over 20 years in the AIDS Linked to the Intravenous Experience (ALIVE) Study, a community-based cohort of injection drug users (IDUs) in Baltimore, Maryland, with a focus on injection cessation. Starting in 1988, persons over 18 years of age with a history of injection drug use were recruited into the study. Participants provided information on their injection drug use semiannually through 2008. The analysis was restricted to 1,716 IDUs with at least 8 study visits. Finite mixture models were used to identify trajectories and predictors of injection patterns over time. The mean age of participants was 35 years; 75% were male, and 95% were African-American. Five distinct patterns were identified: 2 usage patterns (32% engaged in persistent injection and 16% had frequent relapse) and 3 cessation patterns (early cessation (19%), delayed cessation (16%), and late cessation (18%)). A history of drug treatment, no recent use of multiple substances, and less frequent injection distinguished the early cessation group from the other groups. This study demonstrated multiple trajectories of drug injection behaviors, with a substantial proportion of IDUs stopping injection over extended time frames. For maximum effectiveness, public health programs for IDUs should be long-term, comprehensive, and targeted toward individual patterns of use.

The STEP into Action study: a peer-based, personal risk network-focused HIV prevention intervention with injection drug users in Baltimore, Maryland

AIMS

To assess the effectiveness of a peer-based, personal risk network-focused HIV prevention intervention to (i) train injection drug users (IDUs) to reduce injection and sex risk behaviors, (ii) conduct outreach to behaviorally risky individuals in their personal social networks [called risk network members (RNM)], and (iii) reduce RNM HIV risk behaviors.

DESIGN

Randomized controlled trial with prospective data collection at 6, 12 and 18 months. Intervention condition consisted of five group sessions, one individual session and one session with Index and the RNM.

SETTING

This study was conducted in Baltimore, Maryland from March 2004 to March 2006.

PARTICIPANTS

(i) Index participants were aged ≥ 18 years and self-reported injection drug use in the prior 6 months and (ii) their RNM who were aged ≥ 18 years and drug users or sex partners of Index.

MEASUREMENTS

Outcomes included: (i) injection risk based on sharing needles, cookers and cotton for injection and drug splitting, (ii) sex risk based on number of sex partners, condom use and exchanging sex and (iii) Index HIV outreach behaviors.

FINDINGS

A total of 227 Index participants recruited 336 RNM. Retention of Index at 18-month follow-up exceeded 85%. Findings suggest that the experimental condition was efficacious at 18 months in reducing Index participant injection risk [odds ratio (OR) = 0.38; 95% confidence interval (CI) = 0.18-0.77), drug-splitting risk (OR = 0.46; 95% CI = 0.25-0.88) and sex risk among Index (OR = 0.53; 95% CI = 0.34-0.86). Significant intervention effect on increased condom use among female RNM was observed (OR = 0.34; 95% CI = 0.18-0.62).

CONCLUSIONS

Training active IDU to promote HIV prevention with behaviorally risky individuals in their networks is feasible, efficacious and sustainable.

Changes in blood-borne infection risk among injection drug users

BACKGROUND

Population-level hepatitis C virus (HCV) infection incidence is a surrogate for community drug-related risk.

METHODS

We characterized trends in human immunodeficiency virus (HIV) and HCV infection incidence and HCV infection prevalence among injection drug users (IDUs) recruited over 4 periods: 1988-1989, 1994-1995, 1998, and 2005-2008. We calculated HIV and HCV infection incidence within the first year of follow-up among IDUs whose test results were negative for these viruses at baseline (n = 2061 and n = 373, respectively). We used Poisson regression to compare trends across groups.

RESULTS

HIV infection incidence declined significantly from 5.5 cases/100 person-years (py) in the 1988-1989 group to 2.0 cases/100 py in the 1994-1995 group to 0 cases/100 py in the 1998 and 2005-2008 groups. Concurrently, HCV infection incidence declined but remained robust (22.0 cases/100 py in the 1988-1989 cohort to 17.2 cases/100 py in the 1994-1995 cohort, 17.9 cases/100 py in the 1998 cohort, and 7.8 cases/100 py in the 2005-2008 cohort; P = .07). Likewise, HCV infection prevalence declined, but chiefly in younger IDUs. For persons aged <39 years, relative to the 1988-1989 cohort, all groups exhibited significant declines (adjusted prevalence ratio [PR] for the 2005-08 cohort, .73; 95% confidence interval [CI], .65-.81). However, for persons aged ≥ 39 years, only the 2005-2008 cohort exhibited declining prevalence compared with the 1988-1989 cohort (adjusted PR, .87; 95% CI, .77-.99).

CONCLUSIONS

Although efforts to reduce blood-borne infection incidence have had impact, this work will need to be intensified for the most transmissible viruses, such as HCV.

Cognitive behavioral theories used to explain injection risk behavior among injection drug users: a review and suggestions for the integration of cognitive and environmental models

Injection drug users (IDUs) are at risk for HIV and viral hepatitis, and risky injection behavior persists despite decades of intervention. Cognitive behavioral theories (CBTs) are commonly used to help understand risky injection behavior. The authors review findings from CBT-based studies of injection risk behavior among IDUs. An extensive literature search was conducted in spring 2007. In total, 33 studies were reviewed- 26 epidemiological and 7 intervention studies. Findings suggest that some theoretical constructs have received fairly consistent support (e.g., self-efficacy, social norms), whereas others have yielded inconsistent or null results (e.g., perceived susceptibility, knowledge, behavioral intentions, perceived barriers, perceived benefits, response efficacy, perceived severity). The authors offer some possible explanations for these inconsistent findings, including differences in theoretical constructs and measures across studies and a need to examine the environmental structures that influence risky behaviors. Greater integration of CBT with a risk environment perspective may yield more conclusive findings and more effective interventions in the future.

HIV and hepatitis B and C incidence rates in US correctional populations and high risk groups: a systematic review and meta-analysis

BACKGROUND

High Human Immunodeficiency Virus (HIV) prevalence and high risk behaviors have been well documented within United States (US) correctional systems. However, uncertainty remains regarding the extent to which placing people in prison or jail increases their risk of HIV infection, and regarding which inmate populations experience an increased incidence of HIV. Describing these dynamics more clearly is essential to understanding how inmates and former detainees may be a source for further spread of HIV to the general US population.

METHODS

The authors conducted a systematic review and meta-analysis of studies describing HIV incidence in US correctional facility residents and, for comparison, in high risk groups for HIV infection, such as non-incarcerated intravenous drug users (IVDU) and men who have sex with men (MSM) in the US. HIV incidence rates were further compared with Hepatitis B and Hepatitis C Virus rates in these same populations.

RESULTS

Thirty-six predominantly prospective cohort studies were included. Across all infection outcomes, continuously incarcerated inmates and treatment recruited IVDU showed the lowest incidence, while MSM and street recruited IVDU showed the highest. HIV incidence was highest among inmates released and re-incarcerated. Possible sources of heterogeneity identified among HIV studies were risk population and race.

CONCLUSIONS

Although important literature gaps were found, current evidence suggests that policies and interventions for HIV prevention in correctional populations should prioritize curtailing risk of infection during the post-release period. Future research should evaluate HIV incidence rates in inmate populations, accounting for proportion of high risk sub-groups.

Low incidences of human immunodeficiency virus and hepatitis C virus infection and declining risk behaviors in a cohort of injection drug users in Chennai, India

The authors characterized human immunodeficiency virus (HIV) and hepatitis C virus (HCV) incidence and prospective changes in self-reported risk behavior over 2 years among 1,158 injection drug users (IDUs) recruited in Chennai, India, in 2005-2006. At baseline, HIV prevalence was 25.3%, and HCV prevalence was 54.5%. Seropositive persons with prevalent HIV infection were used to estimate baseline HIV incidence by means of the Calypte HIV-1 BED Incidence EIA (Calypte Biomedical Corporation, Portland, Oregon). Longitudinal HIV and HCV incidence were measured among 865 HIV-negative IDUs and 519 HCV antibody-negative IDUs followed semiannually for 2 years. Participants received pre- and posttest risk reduction counseling at each visit. Estimated HIV incidence at baseline was 2.95 per 100 person-years (95% confidence interval (CI): 1.21, 4.69) by BED assay; observed HIV incidence over 1,262 person-years was 0.48 per 100 person-years (95% CI: 0.17, 1.03). HCV incidence over 645 person-years was 1.71 per 100 person-years (95% CI: 0.85, 3.03). Self-reported risk behaviors declined significantly over time, from 100% of participants reporting drug injection at baseline to 11% at 24 months. In this cohort with high HIV and HCV prevalence at enrollment, the authors observed low incidence and declining self-reported risk behavior over time. While no formal intervention was administered, these findings highlight the potential impact of voluntary counseling and testing in a high-risk cohort.

Relationships over time between mental health symptoms and transmission risk among persons living with HIV

Relationships between mental health symptoms (anxiety and depression) or a positive state of mind and behavior associated with HIV transmission (substance use and risky sexual behavior) were explored in a longitudinal study of persons living with HIV (PLH; N = 936) who were participants in a transmission-prevention trial. Bivariate longitudinal regressions were used to estimate the correlations between mental health symptoms and HIV-related transmission acts for 3 time frames: at the baseline interview, over 25 months, and from assessment to assessment. At baseline, mental health symptoms were associated with transmission acts. Elevated levels of mental health symptoms at baseline were associated with decreasing alcohol or marijuana use over 25 months. Over 25 months, an increasingly positive state of mind was associated with decreasing alcohol or marijuana use; an increasingly positive state of mind in the immediate intervention condition and increasing depressive symptoms in the lagged condition were related to increasing risky sexual behavior. Our findings suggest that mental health symptoms precede a decrease in substance use and challenge self-medication theories. Changes in mental health symptoms and sexual behavior occur more in tandem.

Effect of cigarette smoking on HIV acquisition, progression, and mortality

Cigarette smoking is more common among those with HIV compared with the general population. However, it remains unclear whether smoking alters the natural history of HIV infection or if unique health consequences related to smoking occur in the context of HIV. In this article, we review the literature on the effect of smoking on acquisition of HIV, progression of HIV to AIDS, and mortality. Although there was significant heterogeneity in the study populations evaluated, we found little evidence that cigarette smoking increases the risk for acquiring HIV. Two studies observed that smoking was associated with more rapid CD4 cell count declines, but most data suggest that smoking does not accelerate progression to clinical AIDS. The most consistent finding was an increased risk for respiratory infections in smokers. Although no effect of smoking was seen with AIDS-related mortality, findings related to all-cause mortality were inconclusive. Owing to an increase in chronic non-AIDS outcomes in the post-highly active antiretroviral therapy (HAART) era, smoking is likely an increasingly important contributor to morbidity and mortality in HIV-infected populations. Future investigation of the biological and clinical effects of smoking, and of preventive approaches to reduce the heavy burden among individuals with HIV is warranted.

Variations in sexual risks in drug users: emerging themes in a behavioral context

Drug users are an especially complex population among those studied in HIV risk behavior research. Although injection drug use accounts for over one third of the cumulative HIV transmission in the United States, the scope of the direct and indirect impacts of all drug use is difficult to quantify, especially in relation to attributing HIV to drug use directly, via parenteral exposures, or indirectly, through unsafe sex. Important behavioral issues such as social and drug network overlaps, partner selection, and the combinations of illicit drugs with erectile dysfunction medications have added complexity to the study of sexual behavior in drug users. This review covers recent substantive research in the United States and Canada on current themes in sexual risk behavior in injection drug and non-injection drug users. We address gender, situational, and sexual preference factors that may influence sexual behaviors affecting HIV risk by class of drug and route of administration. Special attention is paid to minority populations, both sexual and racial/ethnic, as their marginalized role in contemporary society places special barriers to risk reduction.

High prevalence of HIV, HIV/hepatitis C virus coinfection, and risk behaviors among injection drug users in Chennai, India: a cause for concern

OBJECTIVE

To estimate the prevalence of HIV and hepatitis C virus (HCV) and hepatitis B virus (HBV) coinfections and current risk behaviors among HIV-positive and -negative injection drug users (IDUs) in Chennai, India.

METHODS

Cross-sectional analysis of a convenience sample of 912 IDUs recruited between March 2004 and April 2005. Specimens were tested for HIV, HBV, and HCV. Adjusted prevalence ratios (PRs) were estimated using Poisson regression with robust variance estimates.

RESULTS

The prevalence of HIV, hepatitis B surface antigen, and anti-HCV were 29.8%, 11.1%, and 62.1%, respectively. Among HIV-infected IDUs, prevalence of coinfection with anti-HCV and hepatitis B surface antigen/anti-HCV were 86% and 9.2%, respectively. In multivariate analysis, injecting at a dealer's place (PR: 1.57) and duration of injection drug use >or=11 years (PR: 3.02) were positively associated with prevalent HIV infection. Contrastingly, alcohol consumption >or=1 per week (PR: 0.55) was negatively associated with HIV. HIV-positive IDUs were as or more likely compared with HIV-negative IDUs to report recent high-risk injection-related behaviors.

CONCLUSIONS

There is a high burden of HIV, HCV, and HBV among IDUs that needs to be addressed by improving access to therapies for these infections; furthermore, preventive measures are urgently needed to prevent further spread of HIV, HBV, and HCV in this vulnerable population.

Seroprevalence of select bloodborne pathogens and associated risk behaviors among injection drug users in the Paso del Norte region of the United States-Mexico border

BACKGROUND

The region situated where the borders of Mexico, Texas and New Mexico meet is known as 'Paso del Norte'. The Paso del Norte Collaborative was formed to study the seroprevalence of select pathogens and associated risk behaviors among injection drug users (IDUs) in the region.

METHODS

Respondent-driven sampling (RDS) was used: 459 IDU participants included 204 from Mexico; 155 from Texas; and 100 from New Mexico. Each of the three sites used a standardized questionnaire that was verbally administered and testing was performed for select bloodborne infections.

RESULTS

Participants were mostly male (87.4%) and Hispanic/Latino (84.7%) whose median age was 38. In Mexico, Texas and New Mexico, respectively: hepatitis B virus (HBV) was seen in 88.3%, 48.6% and 59.6% of participants; hepatitis C virus (HCV) in 98.7%, 76.4% and 80.0%; human immunodeficiency virus (HIV) in 2.1%, 10.0% and 1.0%; and syphilis in 4.0%, 9.9% and 3.0%. Heroin was the drug injected most often. More IDUs in New Mexico were aware of and used needle exchange programs compared with Texas and Mexico.

CONCLUSION

There was mixed success using RDS: it was more successfully applied after establishing good working relationships with IDU populations. Study findings included similarities and distinctions between the three sites that will be used to inform prevention interventions.

Effects of behavioral intervention on substance use among people living with HIV: the Healthy Living Project randomized controlled study

AIM

Reductions in substance use were examined in response to an intensive intervention with people living with human immunodeficiency virus (HIV) (PLH).

DESIGN, SETTING AND PARTICIPANTS

A randomized controlled trial was conducted with 936 PLH who had recently engaged in unprotected sexual risk acts recruited from four US cities: Milwaukee, San Francisco, New York and Los Angeles. Substance use was assessed as the number of days of use of 19 substances recently (over the last 90 days), evaluated at 5-month intervals over 25 months.

INTERVENTION

A 15-session case management intervention was delivered to PLH in the intervention condition; the control condition received usual care.

MEASUREMENTS

An intention-to-treat analysis was conducted examining reductions on multiple indices of recent substance use calculated as the number of days of use.

FINDINGS

Reductions in recent substance use were significantly greater for intervention PLH compared to control PLH: alcohol and/or marijuana use, any substance use, hard drug use and a weighted index adjusting for seriousness of the drug. While the intervention-related reductions in substance use were larger among women than men, men also reduced their use. Compared to controls, gay and heterosexual men in the intervention reduced significantly their use of alcohol and marijuana, any substance, stimulants and the drug severity-weighted frequency of use index. Gay men also reduced their hard drug use significantly in the intervention compared to the control condition.

CONCLUSIONS

A case management intervention model, delivered individually, is likely to result in significant and sustained reductions in substance use among PLH.

Cautionary comments on an ethnographic tale gone wrong

Greg Scott's paper, "'They got their program, and I got mine": a cautionary tale concerning the ethical implications of using respondent-driven sampling to study injection drug users' (Scott, 2008) is seriously flawed by (1) a near complete lack of context in assessing ethical implications of respondent-driven sampling, (2) ignoring the ethnographer's impact on what is observed, (3) a seemingly bedrock belief that the intimacy of ethnographic interviews produces truth, and (4) a misreading of power relationships. Some scenarios depicted in the paper appear inauthentic and the consistency of reported hustles strains credibility. The paper fails further by not situating respondent-driven sampling within the broader array of word-of-mouth recruiting methods and by ignoring advantages RDS may confer both in improving the quality of data and in anticipating the possibility of coercive recruiting.

Health and health behaviors in HIV-infected jail inmates, 1999 and 2005

Incarcerated HIV-infected persons in San Francisco have benefited from intensive case management in jail and postrelease, which includes but is not focused on interventions to prevent transmission. In this population of predominately injection drug users (IDUs), we had the opportunity to examine interview data from 1999 and 2005 that included health characteristics and risk factors. Those in 2005 were less likely to be satisfied with social support and less likely to be partnered; more likely to have some form of health insurance. On average, health was perceived in both periods to be better the longer the person had been in jail. Injection drug use was reported lower in 2005, but a subset of nearly a quarter in each survey time period reported sharing needles. Persons in 2005 were less likely to report they always used condoms as compared to those in 1999 (odds ratio 0.26, 95% confidence interval 0.12-0.59, p = 0.001). While there were differences in study design and methodology, this comparison demonstrated overall similarities in characteristics of HIV-infected inmates. Findings echo those of others, in other populations of HIV-infected persons. Reasons could include HIV prevention fatigue or decay in effectiveness of prevention messages. Despite an established program for case management and links to services, renewed efforts are needed to maintain effectiveness of prevention strategies to this high-risk population.