HIV prevalence rates among injection drug users in 96 large US metropolitan areas, 1992-2002

Project CHARIOT: study protocol for a hybrid type 1 effectiveness-implementation study of comprehensive tele-harm reduction for engagement of people who inject drugs in HIV prevention services

BACKGROUND

People who inject drugs (PWID) remain a high priority population under the federal Ending the HIV Epidemic initiative with 11% of new HIV infections attributable to injection drug use. There is a critical need for innovative, efficacious, scalable, and community-driven models of healthcare in non-stigmatizing settings for PWID. We seek to test a Comprehensive-TeleHarm Reduction (C-THR) intervention for HIV prevention services delivered via a syringe services program (SSP).

METHODS

The CHARIOT trial is a hybrid type I effectiveness-implementation study using a parallel two-arm randomized controlled trial design. Participants (i.e., PWID; n = 350) will be recruited from a syringe services program (SSP) in Miami, Florida. Participants will be randomized to receive either C-THR or non-SSP clinic referral and patient navigation. The objectives are: (1) to determine if the C-THR intervention increases engagement in HIV prevention (i.e., HIV pre-exposure prophylaxis; PrEP or medications for opioid use disorder; MOUD) compared to non-SSP clinic referral and patient navigation, (2) to examine the long-term effectiveness and cost-effectiveness of the C-THR intervention, and (3) to assess the barriers and facilitators to implementation and sustainment of the C-THR intervention. The co-primary outcomes are PrEP or MOUD engagement across follow-up at 3, 6, 9 and 12 months. For PrEP, engagement is confirmed by tenofovir on dried blood spot or cabotegravir injection within the previous 8 weeks. For MOUD, engagement is defined as screening positive for norbuprenorphine or methadone on urine drug screen; or naltrexone or buprenorphine injection within the previous 4 weeks. Secondary outcomes include PrEP adherence, engagement in HCV treatment and sustained virologic response, and treatment of sexually transmitted infections. The short and long term cost-effectiveness analyses and mixed-methods implementation evaluation will provide compelling data on the sustainability and possible impact of C-THR on comprehensive HIV prevention delivered via SSPs.

DISCUSSION

The CHARIOT trial will be the first to our knowledge to test the efficacy of an innovative, peer-led telehealth intervention with PWID at risk for HIV delivered via an SSP. This innovative healthcare model seeks to transform the way PWID access care by bypassing the traditional healthcare system, reducing multi-level barriers to care, and meeting PWID where they are.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05897099. Trial registry name: Comprehensive HIV and Harm Prevention Via Telehealth (CHARIOT). Registration date: 06/12/2023.

Egocentric network characteristics of people who inject drugs in the Chicago metro area and associations with hepatitis C virus and injection risk behavior

BACKGROUND

Hepatitis C (HCV) infection has been rising in the suburban and rural USA, mainly via injection-based transmission. Injection and sexual networks are recognized as an important element in fostering and preventing risky behavior; however, the role of social support networks has received somewhat less attention.

METHODS

Using baseline data from an ongoing longitudinal study, we examined the composition and structure of injection drug use (IDU), sex, and social support networks of young people who inject drugs (aged 18-30) and their injection network members. Lasso logistic regression was used to select a subset of network characteristics that were potentially important predictors of injection risk behaviors and HCV exposure.

RESULTS

Several measures of IDU, sexual, and support network structure and composition were found to be associated with HCV exposure, receptive syringe sharing (RSS), and ancillary equipment sharing. Gender and sexual relationships were important factors for all risk behaviors. Support network characteristics were also important, notably including a protective effect of majority Hispanic support networks for RSS and HCV exposure. Both IDU network residence heterogeneity and support network geography were associated with injection equipment sharing.

CONCLUSIONS

The associations of IDU and support network geography with equipment sharing highlight the need to extend harm reduction efforts beyond urban areas. Greater understanding of support network influences on risk behavior may provide important insights to strengthen the benefits of harm reduction. In considering the probability of HCV transmission, it is important to consider setting and network structures that promote propagation of risk.

Trends over time in HIV prevalence among people who inject drugs in 89 large US metropolitan statistical areas, 1992-2013

PURPOSE

After years of stable or declining HIV prevalence and declining incidence among people who inject drugs (PWID) in the United States, some rapidly emerging outbreaks have recently occurred in new areas (e.g., Scott County, Indiana). However, to our knowledge, trends over time in HIV prevalence among PWID in US metropolitan statistical areas (MSAs) across all major regions of the country have not been systematically estimated beyond 2002, and the extent to which HIV prevalence may be increasing in other areas is largely unknown. This article estimates HIV prevalence among PWID in 89 of the most populated US MSAs, both overall and by geographic region, using more recent surveillance and HIV testing data.

METHODS

We computed MSA-specific annual estimates of HIV prevalence (both diagnosed and undiagnosed infections) among PWID for these 89 MSAs, for 1992-2013, using several data series from the Centers for Disease Control and Prevention's (CDC) National HIV Surveillance System and National HIV Prevention Monitoring and Evaluation data; Holmberg's (1997) estimates of 1992 PWID population size and of HIV prevalence and incidence among PWID; and research estimates from published literature using 1992-2013 data. A mixed effects model, with time nested within MSAs, was used to regress the literature review estimates on all of the other data series. Multiple imputation was used to address missing data. Resulting estimates were validated using previous 1992-2002 estimates of HIV prevalence and data on antiretroviral (ARV) prescription volumes and examined for patterns based on geographic region, numbers of people tested for HIV, and baseline HIV prevalence.

RESULTS

Mean (across all MSAs) trends over time suggested decreases through 2002 (from approximately 11.4% in 1992 to 9.2% in 2002), followed by a period of stability, and steep increases after 2010 (to 10.6% in 2013). Validation analyses found a moderate positive correlation between our estimates and ARV prescription volumes (r = 0.45), and a very strong positive correlation (r = 0.94) between our estimates and previous estimates by Tempalski et al. (2009) for 1992-2002 (which used different methods). Analysis by region and baseline prevalence suggested that mean increases in later years were largely driven by MSAs in the Western United States and by MSAs in the Midwest that had low baseline prevalence. Our estimates suggest that prevalence decreased across all years in the Eastern United States. These trends were particularly clear when MSAs with very low numbers of people tested for HIV were removed from analyses to reduce unexplained variability in mean trajectories.

CONCLUSIONS

Our estimates suggest a fairly large degree of variation in 1992-2013 trajectories of PWID HIV prevalence among 89 US MSAs, particularly by geographic region. They suggest that public health responses in many MSAs (particularly those with larger HIV prevalence among PWID in the early 1990s) were sufficient to decrease or maintain HIV prevalence over time. However, future research should investigate potential factors driving the estimated increase in prevalence after 2002 MSAs in the West and Midwest. These findings have potentially important implications for program and/or policy decisions, but estimates for MSAs with low HIV testing denominators should be interpreted with caution and verified locally before planning action.

Heroin type, injecting behavior, and HIV transmission. A simulation model of HIV incidence and prevalence

BACKGROUND AND AIMS

Using mathematical modeling to illustrate and predict how different heroin source-forms: "black tar" (BTH) and powder heroin (PH) can affect HIV transmission in the context of contrasting injecting practices. By quantifying HIV risk by these two heroin source-types we show how each affects the incidence and prevalence of HIV over time. From 1997 to 2010 PH reaching the United States was manufactured overwhelmingly by Colombian suppliers and distributed in the eastern states of the United States. Recently Mexican cartels that supply the western U.S. states have started to produce PH too, replacing Colombian distribution to the east. This raises the possibility that BTH in the western U.S. may be replaced by PH in the future.

DESIGN

We used an agent-based model to evaluate the impact of use of different heroin formulations in high- and low-risk populations of persons who inject drugs (PWID) who use different types of syringes (high vs. low dead space) and injecting practices. We obtained model parameters from peer-reviewed publications and ethnographic research.

RESULTS

Heating of BTH, additional syringe rinsing, and subcutaneous injection can substantially decrease the risk of HIV transmission. Simulation analysis shows that HIV transmission risk may be strongly affected by the type of heroin used. We reproduced historic differences in HIV prevalence and incidence. The protective effect of BTH is much stronger in high-risk compared with low-risk populations. Simulation of future outbreaks show that when PH replaces BTH we expect a long-term overall increase in HIV prevalence. In a population of PWID with mixed low- and high-risk clusters we find that local HIV outbreaks can occur even when the overall prevalence and incidence are low. The results are dependent on evidence-supported assumptions.

CONCLUSIONS

The results support harm-reduction measures focused on a reduction in syringe sharing and promoting protective measures of syringe rinsing and drug solution heating.

Sex under Influence of Drugs: A Nationwide Survey among Iranian Female Sex Workers

Background

Due to the high level of sexual relationships, prostitute women are faced with many dangers, including acquired immune deficiency syndrome (AIDS), sexually transmitted infections (STIs), fertility problems, drug use, etc. In this regard, addict prostitute women are exposed to more risks because drug use is considered as an outstanding factor in those associated with transmission of AIDS and being in an insecure sexual relationship. The purpose of this study was to find out the variables influential on the level of drug use, before or during sexual relationship.

Methods

In 2010, 625 prostitute women were selected by multistage sampling from 21 centers out of 12 provinces. Then, we used a standard questionnaire for gathering data by a face-to-face interview. The multilevel ordinal logistic regression in survey model was used to find out the relationship between variables and the level of drug use before or during sexual relationship.

Findings

The number of monetary customers at the last working day [adjusted odds ratio (AOR): 1.87, 95% confidence interval (CI): 1.50-2.32] and having sexual relationship during the past month with monetary customers (AOR: 4.77, 95% CI: 2.61-8.70) were significantly related to the level of drug use before or during sexual relationship in the past month.

Conclusion

Since the level of drug use before or during sexual relationship was higher in women who had more daily sexual relationships, these women are exposed to the consequences of drug use; thus, identifying the status of this group of women is important to plan for future injuries.

Baseline differences in characteristics and risk behaviors among people who inject drugs by syringe exchange program modality: an analysis of the Miami IDEA syringe exchange

Background

In March of 2016, Florida passed the Infection Disease Elimination Act (IDEA), legalizing the formation of the first syringe exchange program in Florida, which opened in December of 2016 at a fixed site in Overtown, Miami. Since that time, the exchange expanded in April of 2017 to include a mobile van unit that provides the same services at different locations throughout Miami-Dade County.

Methods

Trained interviewers conducted face-to-face interviews from all first-time participants at the IDEA Exchange, both at the fixed site and the mobile van unit.

Results

Among 718 first-time enrollees, 74.8% were male, 52.1% were non-Hispanic White, 85.9% completed high school, 59.8% were unemployed, 42.1% were homeless, 54.2% reported an annual income of less than $15,000, and the mean age was 38 years. Participants at the fixed site and mobile van unit reported differences in socioeconomic status, injection drug-related behaviors, and pre-existing hepatitis C virus (HCV) infection status.

Conclusions

Taken together, these results suggest that the mobile unit is capturing a subset of PWID in Miami that the fixed site is not, and vice-versa. As the opioid crisis extends into all demographics, such multimodal efforts to target various populations of PWID should be kept in mind, especially when unveiling future syringe exchanges in Florida and other late-adopting states.

Estimating the Size of the MSM Population in Metro Vancouver, Canada, Using Multiple Methods and Diverse Data Sources

Men who have sex with men (MSM) are disproportionately affected by HIV globally, regionally in Canada, and locally in Vancouver. Lack of reliable population size estimates of MSM impedes effective implementation of health care services and limits our understanding of the HIV epidemic. We estimated the population size of MSM residing in Metro Vancouver drawing on four data sources: the Canadian Community Health Survey (CCHS), a cross-sectional bio-behavioural MSM survey, HIV testing services data from sexually transmitted infection (STI) clinics serving MSM, and online social networking site Facebook. Estimates were calculated using (1) direct estimates from the CCHS, (2) "Wisdom of the Crowds" (WOTC), and (3) the multiplier method using data from a bio-behavioural MSM survey, clinic-based HIV testing, and online social media network site Facebook. Data sources requiring greater public disclosure of sexual orientation resulted in our mid-range population estimates (Facebook 23,760, CCHS 30,605). The WOTC method produced the lowest estimate, 10,000. The multiplier method using STI clinic HIV testing data produced the largest estimate, 41,777. The median of all estimates was 27,183, representing 2.9% of the Metro Vancouver census male adult population, with an interquartile range of 1.1-4.5%. Using multiple data sources, our estimates of the MSM population in Metro Vancouver are similar to population prevalence estimates based on population data from other industrialized nations. These findings will support understanding of the HIV burden among MSM and corresponding public health and health services planning for this key population.

Seroprevalence of HCV and HIV infection among clients of the nation's longest-standing statewide syringe exchange program: A cross-sectional study of Community Health Outreach Work to Prevent AIDS (CHOW)

BACKGROUND

The Community Health Outreach Work to Prevent AIDS (CHOW) Project is the first and longest-standing statewide integrated and funded needle and syringe exchange program (SEP) in the US. Initiated on O'ahu in 1990, CHOW expanded statewide in 1993. The purpose of this study is to estimate the prevalences of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection, and to characterize risk behaviors associated with infection among clients of a long-standing SEP through the analysis of the 2012 CHOW evaluation data.

METHODS

A cross-sectional sample of 130 CHOW Project clients was selected from January 1, 2012 through December 31, 2012. Questionnaires captured self-reported exposure information. HIV and HCV antibodies were detected via rapid, point-of-care FDA-approved tests. Log-binomial regressions were used to estimate prevalence proportion ratios (PPRs). A piecewise linear log-binomial regression model containing 1 spline knot was used to fit the age-HCV relationship.

RESULTS

The estimated seroprevalence of HCV was 67.7% (95% confidence interval [CI]=59.5-75.8%). HIV seroprevalence was 2.3% (95% CI=0-4.9%). Anti-HCV prevalence demonstrated age-specific patterns, ranging from 31.6% through 90.9% in people who inject drugs (PWID) <30 to ≥60 years respectively. Age (continuous/year) prior to spline knot at 51.5 years (adjusted PPR [APPR]=1.03; 95% CI=1.02-1.05) and months exchanging syringes (quartiles) (APPR=1.92; 95% CI=1.3-3.29) were independently associated with anti-HCV prevalence.

CONCLUSION

In Hawai'i, HCV prevalence among PWID is hyperendemic demonstrating age- and SEP duration-specific trends. Relatively low HIV prevalence compared with HCV prevalence reflects differences in transmissibility of these 2 blood-borne pathogens and suggests much greater efficacy of SEP for HIV prevention.

The Effectiveness of the Harm Reduction Group Therapy Based on Bandura's Self-Efficacy Theory on Risky Behaviors of Drug-Dependent Sex Worker Women

BACKGROUND

The aim of this study was to investigate the effectiveness of the harm reduction group therapy based on Bandura's self-efficacy theory on risky behaviors of sex workers in Kerman, Iran.

METHODS

A quasi-experimental two-group design (a random selection with pre-test and post-test) was used. A risky behaviors questionnaire was used to collect. The sample was selected among sex workers referring to drop-in centers in Kerman. Subjects were allocated to two groups and were randomly classified into two experimental and control groups. The sample group consisted of 56 subjects. The experimental design was carried out during 12 sessions, and the post-test was performed one month and two weeks after the completion of the sessions. The results were analyzed statistically.

FINDINGS

By reducing harm based on Bandura's self-efficacy theory, the risky behaviors of the experimental group, including injection behavior, sexual behavior, violence, and damage to the skin, were significantly reduced in the pre-test compared to the post-test (P < 0.010).

CONCLUSION

The harm reduction group therapy based on Bandura's self-efficacy theory can reduce the risky behaviors of sex workers.

Acute HIV infection transmission among people who inject drugs in a mature epidemic setting

OBJECTIVE

Estimates for the contribution of transmission arising from acute HIV infections (AHIs) to overall HIV incidence vary significantly. Furthermore, little is known about AHI-attributable transmission among people who inject drugs (PWID), including the extent to which interventions targeting chronic infections (e.g. HAART as prevention) are limited by AHI transmission. Thus, we estimated the proportion of transmission events attributable to AHI within the mature HIV epidemic among PWID in New York City (NYC).

DESIGN

Modeling study.

METHODS

We constructed an interactive sexual and injecting transmission network using an agent-based model simulating the HIV epidemic in NYC between 1996 and 2012. Using stochastic microsimulations, we cataloged transmission from PWID based on the disease stage of index agents to determine the proportion of infections transmitted during AHI (in primary analyses, assumed to last 3 months).

RESULTS

Our calibrated model approximated the epidemiological features of the mature HIV epidemic in NYC between 1996 and 2012. Annual HIV incidence among PWID dropped from approximately 1.8% in 1996 to 0.7% in 2012. Over the 16-year period, AHI accounted for 4.9% (10th/90th percentile: 0.1-12.3%) of incident HIV cases among PWID. The annualized contribution of AHI increased over this period from 3.6% in 1996 to 5.9% in 2012.

CONCLUSION

Our results suggest that, in mature epidemics such as NYC, between 3% and 6% of transmission events are attributable to AHI among PWID. Current HIV treatment as prevention strategies are unlikely to be substantially affected by AHI-attributable transmission among PWID populations in mature epidemic settings.

Associations of place characteristics with HIV and HCV risk behaviors among racial/ethnic groups of people who inject drugs in the United States

PURPOSE

Investigate whether characteristics of geographic areas are associated with condomless sex and injection-related risk behavior among racial/ethnic groups of people who inject drugs (PWID) in the United States.

METHODS

PWID were recruited from 19 metropolitan statistical areas for 2009 National HIV Behavioral Surveillance. Administrative data described ZIP codes, counties, and metropolitan statistical areas where PWID lived. Multilevel models, stratified by racial/ethnic groups, were used to assess relationships of place-based characteristics to condomless sex and injection-related risk behavior (sharing injection equipment).

RESULTS

Among black PWID, living in the South (vs. Northeast) was associated with injection-related risk behavior (adjusted odds ratio [AOR] = 2.24, 95% confidence interval [CI] = 1.21-4.17; P = .011), and living in counties with higher percentages of unaffordable rental housing was associated with condomless sex (AOR = 1.02, 95% CI = 1.00-1.04; P = .046). Among white PWID, living in ZIP codes with greater access to drug treatment was negatively associated with condomless sex (AOR = 0.93, 95% CI = 0.88-1.00; P = .038).

CONCLUSIONS

Policies that increase access to affordable housing and drug treatment may make environments more conducive to safe sexual behaviors among black and white PWID. Future research designed to longitudinally explore the association between residence in the south and injection-related risk behavior might identify specific place-based features that sustain patterns of injection-related risk behavior.

Cost-Effectiveness of Frequent HIV Testing of High-Risk Populations in the United States

PURPOSE

Data showing a high incidence of HIV infection among men who have sex with men (MSM) who had annual testing suggest that more frequent HIV testing may be warranted. Testing technology is also a consideration given the availability of sensitive testing modalities and the increased use of less-sensitive rapid, point-of-care antibody tests. We assessed the cost-effectiveness of HIV testing of MSM and injection drug users (IDUs) at 3- and 6-month intervals using fourth-generation and rapid tests.

METHODS

We used a published mathematical model of HIV transmission to evaluate testing intervals for each population using cohorts of 10,000 MSM and IDU. We incorporated HIV transmissions averted due to serostatus awareness and viral suppression. We included costs for HIV testing and treatment initiation, and also treatment costs saved from averted transmissions.

RESULTS

For MSM, HIV testing was cost saving or cost effective over a 1-year period for both 6-month compared with annual testing and quarterly compared with 6-month testing using either test. Testing IDU every 6 months compared with annually was moderately cost effective over a 1-year period with a fourth-generation test, while testing with rapid, point-of-care tests or quarterly was not cost effective. MSM results remained robust in sensitivity analysis, whereas IDU results were sensitive to changes in HIV incidence and continuum-of-care parameters. Threshold analyses on costs suggested that additional implementation costs could be incurred for more frequent testing for MSM while remaining cost effective.

CONCLUSIONS

HIV testing of MSM as frequently as quarterly is cost effective compared with annual testing, but testing IDU more frequently than annually is generally not cost effective.

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.

Risk Environments, Race/Ethnicity, and HIV Status in a Large Sample of People Who Inject Drugs in the United States

INTRODUCTION

We analyzed relationships between place characteristics and being HIV-negative among black, Latino, and white people who inject drugs (PWID) in the US.

METHODS

Data on PWID (N = 9077) were from the Centers for Disease Control and Prevention's 2009 National HIV Behavioral Surveillance. Administrative data were analyzed to describe the 968 ZIP codes, 51 counties, and 19 metropolitan statistical areas (MSAs) where they lived. Multilevel multivariable models examined relationships between place characteristics and HIV status. Exploratory population attributable risk percents (e-PAR%s) were estimated.

RESULTS

Black and Latino PWID were more likely to be HIV-negative if they lived in less economically disadvantaged counties, or in MSAs with less criminal-justice activity (i.e., lower drug-related arrest rates, lower policing/corrections expenditures). Latino PWID were more likely to be HIV-negative in MSAs with more Latino isolation, less black isolation, and less violent crime. E-PAR%s attributed 8-19% of HIV cases among black PWID and 1-15% of cases among Latino PWID to place characteristics.

DISCUSSION

Evaluations of structural interventions to improve economic conditions and reduce drug-related criminal justice activity may show evidence that they protect black and Latino PWID from HIV infection.

Income inequality, drug-related arrests, and the health of people who inject drugs: Reflections on seventeen years of research

This paper reviews and then discusses selected findings from a seventeen year study about the population prevalence of people who inject drugs (PWID) and of HIV prevalence and mortality among PWID in 96 large US metropolitan areas. Unlike most research, this study was conducted with the metropolitan area as the level of analysis. It found that metropolitan area measures of income inequality and of structural racism predicted all of these outcomes, and that rates of arrest for heroin and/or cocaine predicted HIV prevalence and mortality but did not predict changes in PWID population prevalence. Income inequality and measures of structural racism were associated with hard drug arrests or other properties of policing. These findings, whose limitations and implications for further research are discussed, suggest that efforts to respond to HIV and to drug injection should include supra-individual efforts to reduce both income inequality and racism. At a time when major social movements in many countries are trying to reduce inequality, racism and oppression (including reforming drug laws), these macro-social issues in public health should be both addressable and a priority in both research and action.

Modeling a dynamic bi-layer contact network of injection drug users and the spread of blood-borne infections

Injection drug users (IDUs) are at high risk of acquiring and spreading various blood-borne infections including human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV) and a number of sexually transmitted infections. These infections can spread among IDUs via risky sexual and needle-sharing contacts. To accurately model the spread of such contagions among IDUs, we build a bi-layer network that captures both types of risky contacts. We present methodology for inferring important model parameters, such as those governing network structure and dynamics, from readily available data sources (e.g., epidemiological surveys). Such a model can be used to evaluate the efficacy of various programs that aim to combat drug addiction and contain blood-borne diseases among IDUs. The model is especially useful for evaluating interventions that exploit the structure of the contact network. To illustrate, we instantiate a network model with data collected by a needle and syringe program in Chicago. We model sexual and needle-sharing contacts and the consequent spread of HIV and HCV. We use the model to evaluate the potential effects of a peer education (PE) program under different targeting strategies. We show that a targeted PE program would avert significantly more HIV and HCV infections than an untargeted program, highlighting the importance of reaching individuals who are centrally located in contact networks when instituting prevention programs.

Understanding the effects of different HIV transmission models in individual-based microsimulation of HIV epidemic dynamics in people who inject drugs

We investigated how different models of HIV transmission, and assumptions regarding the distribution of unprotected sex and syringe-sharing events ('risk acts'), affect quantitative understanding of HIV transmission process in people who inject drugs (PWID). The individual-based model simulated HIV transmission in a dynamic sexual and injecting network representing New York City. We constructed four HIV transmission models: model 1, constant probabilities; model 2, random number of sexual and parenteral acts; model 3, viral load individual assigned; and model 4, two groups of partnerships (low and high risk). Overall, models with less heterogeneity were more sensitive to changes in numbers risk acts, producing HIV incidence up to four times higher than that empirically observed. Although all models overestimated HIV incidence, micro-simulations with greater heterogeneity in the HIV transmission modelling process produced more robust results and better reproduced empirical epidemic dynamics.

Low Rates of Adoption and Implementation of Rapid HIV Testing in Substance Use Disorder Treatment Programs

INTRODUCTION

Rapid HIV testing (RHT) greatly increases the proportion of clients who learn their test results. However, existing studies have not examined the adoption and implementation of RHT in programs treating persons with substance use disorders, one of the population groups at higher risk for HIV infection.

METHODS

We examined 196 opioid treatment programs (OTPs) using data from the 2011 National Drug Abuse Treatment System Survey (NDATSS). We used logistic regressions to identify client and organizational characteristics of OTPs associated with availability of on-site RHT. We then used zero-inflated negative binomial regressions to measure the association between the availability of RHT on-site and the number of clients tested for HIV.

RESULTS

Only 31.6% of OTPs offered on-site rapid HIV testing to their clients. Rapid HIV testing was more commonly available on-site in larger, publicly owned and better-staffed OTPs. On the other hand, on-site rapid HIV testing was less common in OTPs that prescribed only buprenorphine as a method of opioid dependence treatment. The availability of rapid HIV testing on-site reduced the likelihood that an OTP did not test any of its clients during the prior year. But on-site availability rapid HIV testing was not otherwise associated with an increased number of clients tested for HIV at an OTP.

CONCLUSIONS

New strategies are needed to a) promote the adoption of rapid HIV testing on-site in substance use disorder treatment programs and b) encourage substance use disorder treatment providers to offer rapid HIV testing to their clients when it is available.

Correlates of HIV testing and receipt of test results in addiction health services in Los Angeles County

Background

HIV testing and receipt of HIV test results among individuals with substance use disorders is less than optimal. We examined rates and correlates of HIV testing and receipt of test results in one of the largest public addiction health services systems in the United States.

Methods

The study included 139,516 adult clients in treatment between 2006 and 2011. We used logistic regression models to examine associations between predisposing, enabling, and need factors and two dependent variables, HIV testing rates and receipt of test results. Associations were considered statistically significance at p < .01.

Results

We found that 64 % of clients reported being tested for HIV, of whom 85 % reported receiving their test results. Likelihood of being tested was positively associated with being female, a minority, homeless, employed, having prior treatment episodes, comorbidities, injection drug use, or a history of mental illness. It was negatively associated with alcohol or marijuana as primary drug. Receipt of test results was more likely among clients on medication (methadone or buprenorphine) or whose method of drug use was smoking, inhalation, or injecting; it was less likely among older clients and those with more outpatient psychiatric visits.

Conclusions

Findings from this study may inform strategies and targeting of population groups to improve HIV testing practices and ultimately increase awareness of infection status among clients of addiction health services.

Comparison of Rapid Point-of-Care Tests for Detection of Antibodies to Hepatitis C Virus

OraSure had the highest sensitivity at 92.7% followed closely by Chembio's three blood tests. False results were associated with HIV, and hepatitis B core antibody. The OraSure and Chembio blood tests have good performance characteristics.

Background. Hepatitis C is one of the most prevalent blood-borne diseases in the United States. Despite the benefits of early screening, among 3.2 million Americans who are infected with hepatitis C virus (HCV), 50%–70% are unaware of their infection status.

Methods. Data were collected between 2011 and 2014, from 1048 clients who were in the following groups: (1) injection drug users, (2) women at sexual risk, (3) gay and bisexual men, and (4) transgender individuals. The sensitivity and specificity of point-of-care tests included (1) the MedMira rapid human immunodeficiency virus (HIV)/HCV antibody test, (2) MedMira hepatitis B (HBV)/HIV/HCV antibody test, (3) Chembio HCV Screen Assay used with both whole blood and (4) oral specimens, (5) Chembio HIV-HCV Assay also used with both whole blood and (6) oral specimens, (7) Chembio HIV-HCV-Syphilis Assay, and (8) OraSure HCV Rapid Antibody Test used with whole blood. The gold standard for the HCV tests were HCV enzyme immunoassay (EIA) 2.0.

Results. OraSure had the highest sensitivity at 92.7% (95% confidence interval [CI] = 88.8%–96.5%) followed closely by Chembio's 3 blood tests at 92.1% (95% CI = 87.7%–96.4%), 91.5% (95% CI = 87.2%–95.7%), and 92.3% (95% CI = 88.4%–96.2%). The sensitivities of MedMira HIV/HCV and MedMira HIV/HCV/HBV tests were the lowest, at 79.1% (95% CI = 72.6%–85.5%), and 81.5% (95% CI = 75.2%–87.8%), respectively. Specificity for the OraSure was 99.8% (95% CI = 99.4%–100%); specificity for the Chembio blood tests was 99.2% (95% CI = 98.6%–99.9%), 99.4% (95% CI = 98.8%–99.9%), and 99.3% (95% CI = 98.8%–99.9%); and specificity for the MedMira was100% and 100%. False-negative results were associated with HIV and hepatitis B core antibody serostatus.

Conclusions. The OraSure and Chembio blood tests (including those multiplexed with HIV and syphilis) appear to good performance characteristics. This study has identified potential limitations of rapid testing in those testing positive for HIV and HBcAb. There should be discussion of updates to the 2013 CDC guidance.

A Cost Analysis of Hospitalizations for Infections Related to Injection Drug Use at a County Safety-Net Hospital in Miami, Florida

Background

Infections related to injection drug use are common. Harm reduction strategies such as syringe exchange programs and skin care clinics aim to prevent these infections in injection drug users (IDUs). Syringe exchange programs are currently prohibited by law in Florida. The goal of this study was to estimate the mortality and cost of injection drug use-related bacterial infections over a 12-month period to the county safety-net hospital in Miami, Florida. Additionally, the prevalence of HIV and hepatitis C virus among this cohort of hospitalized IDUs was estimated.

Methods and Findings

IDUs discharged from Jackson Memorial Hospital were identified using the International Classification of Diseases, Ninth Revision, codes for illicit drug abuse and endocarditis, bacteremia or sepsis, osteomyelitis and skin and soft tissue infections (SSTIs). 349 IDUs were identified for chart abstraction and 92% were either uninsured or had publicly funded insurance. SSTIs, the most common infection, were reported in 64% of IDUs. HIV seroprevalence was 17%. Seventeen patients (4.9%) died during their hospitalization. The total cost for treatment for injection drug use-related infections to Jackson Memorial Hospital over the 12-month period was $11.4 million.

Conclusions

Injection drug use-related bacterial infections represent a significant morbidity for IDUs in Miami-Dade County and a substantial financial cost to the county hospital. Strategies aimed at reducing risk of infections associated with injection drug use could decrease morbidity and the cost associated with these common, yet preventable infections.

Female and male differences in AIDS diagnosis rates among people who inject drugs in large U.S. metro areas from 1993 to 2007

PURPOSE

We estimated female and male incident AIDS diagnosis rates (IARs) among people who inject drugs (PWID) in U.S. metropolitan statistical areas (MSAs) over time to assess whether declines in IARs varied by sex after combination antiretroviral therapy (cART) dissemination.

METHODS

We compared IARs and 95% confidence intervals for female and male PWID in 95 of the most populous MSAs. To stabilize estimates, we aggregated data across three-year periods, selecting a period immediately preceding cART (1993-1995) and the most recent after the introduction of cART for which data were available (2005-2007). We assessed disparities by comparing IAR 95% confidence intervals for overlap, female-to-male risk ratios, and disparity change scores.

RESULTS

IARs declined an average of 58% for female PWID and 67% for male PWID between the pre-cART and cART periods. Among female PWID, IARs were significantly lower in the later period relative to the pre-cART period in 48% of MSAs. Among male PWID, IARs were significantly lower over time in 86% of MSAs.

CONCLUSIONS

IARs among female PWID in large U.S. MSAs have declined more slowly than among male PWID. This suggests a need for increased targeting of prevention and treatment programs and for research on MSA level conditions that may drive differences in declining AIDS rates among female and male PWID.

State laws, syringe exchange, and HIV among persons who inject drugs in the United States: History and effectiveness

In 1981, when acquired immune deficiency syndrome (AIDS) was first observed among persons who inject drugs, almost all US states had laws criminalizing the possession and distribution of needles and syringes for injecting illicit drugs. We reviewed changes to these laws to permit 'syringe exchanges' and the provision of public funding for such programs. Most of the changes in law occurred during the 1990s, 5-10 years later than in many other countries. Public funding of syringe exchanges is associated with lower rates of human immunodeficiency virus (HIV) infection, greater numbers of syringes distributed (a possible causal mechanism), and greater numbers of health and social services provided. Experience in the United states may prove useful in other countries: state, provincial, and local governments may need to move ahead of central governments in addressing HIV infection among persons who inject drugs.

Examining delay discounting of condom-protected sex among opioid-dependent women and non-drug-using control women

BACKGROUND

Opioid-dependent (OD) women tend to engage in unprotected sex with high-risk partners, placing themselves at elevated risk for sexually transmitted HIV infection. This behavior generally persists after completion of interventions that increase sexual HIV risk reduction knowledge and skills, suggesting that decision-making biases may influence HIV transmission among OD women.

METHODS

The primary aim of this report is to examine delay discounting of condom-protected sex among OD women and non-drug-using control women using the novel Sexual Discounting Task (SDT; Johnson and Bruner, 2012). Data were collected from 27 OD women and 33 non-drug-using control women using the SDT, a monetary discounting task, and the Barratt impulsiveness scale (BIS-11).

RESULTS

OD women discounted the value of delayed condom-protected sex more steeply than controls for hypothetical sexual partners in the two sets of paired partner conditions examined. Overall, women discounted condom protected sex more steeply for partners they perceived as being lowest STI risk vs. those they perceived as being highest risk. Steeper discounting of condom-protected sex was significantly associated with higher scores on the BIS-11, but not with discounting of money.

CONCLUSIONS

Delay discounting of condom-protected sex differs between OD women and non-drug-using women, is sensitive to perceived partner risk, and is correlated with a self-report measure of impulsivity, the BIS-11. The effect of delay on sexual decision-making is a critical but underappreciated dimension of HIV risk among women, and the SDT appears to be a promising measure of this domain. Further investigation of these relationships is warranted.

Cost-effectiveness of interventions to prevent HIV and STDs among women: a randomized controlled trial

Injection drug use is a leading transmission route of HIV and STDs, and disease prevention among drug users is an important public health concern. This study assesses cost-effectiveness of behavioral interventions for reducing HIV and STDs infections among injection drug-using women. Cost-effectiveness analysis was conducted from societal and provider perspectives for randomized trial data and Bernoullian model estimates of infections averted for three increasingly intensive interventions: (1) NIDA's standard intervention (SI); (2) SI plus a well woman exam (WWE); and (3) SI, WWE, plus four educational sessions (4ES). Trial results indicate that 4ES was cost-effective relative to WWE, which was dominated by SI, for most diseases. Model estimates, however, suggest that WWE was cost-effective relative to SI and dominated 4ES for all diseases. Trial and model results agree that WWE is cost-effective relative to SI per hepatitis C infection averted ($109 308 for in trial, $6 016 in model) and per gonorrhea infection averted ($9 461 in trial, $14 044 in model). In sensitivity analysis, trial results are sensitive to 5 % change in WWE effectiveness relative to SI for hepatitis C and HIV. In the model, WWE remained cost-effective or cost-saving relative to SI for HIV prevention across a range of assumptions. WWE is cost-effective relative to SI for preventing hepatitis C and gonorrhea. WWE may have similar effects as the costlier 4ES.

Perceived susceptibility to AIDS predicts subsequent HIV risk: a longitudinal evaluation of jail inmates

Theories of health behavior change suggest that perceived susceptibility to illness precedes health-protective behavior. We used a cross-lagged panel design to explore the relationship between perceived susceptibility to AIDS, and HIV risk behavior pre-incarceration and post-release in a sample of 499 jail inmates, a group at high risk for HIV. We also explored moderators of this relationship. HIV risk was calculated with a Bernoulli mathematical process model. Controlling for pre-incarceration HIV risk, perceived susceptibility to AIDS predicted less post-release HIV risk; the reverse relationship was not supported. Consistent with health behavior change theories, perceived susceptibility seemed to partially guide behavior. However, this relationship was not true for everyone. African-Americans and individuals high in borderline personality features exhibited no relationship between perceived susceptibility and changes in HIV risk. This suggests that targeted interventions are needed to use information about risk level to prevent HIV contraction.

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.

Trends in the population prevalence of people who inject drugs in US metropolitan areas 1992-2007

BACKGROUND

People who inject drugs (PWID) have increased risk of morbidity and mortality. We update and present estimates and trends of the prevalence of current PWID and PWID subpopulations in 96 US metropolitan statistical areas (MSAs) for 1992-2007. Current estimates of PWID and PWID subpopulations will help target services and help to understand long-term health trends among PWID populations.

METHODOLOGY

We calculated the number of PWID in the US annually from 1992-2007 and apportioned estimates to MSAs using multiplier methods. We used four types of data indicating drug injection to allocate national annual totals to MSAs, creating four distinct series of component estimates of PWID in each MSA and year. The four component estimates are averaged to create the best estimate of PWID for each MSA and year. We estimated PWID prevalence rates for three subpopulations defined by gender, age, and race/ethnicity. We evaluated trends using multi-level polynomial models.

RESULTS

PWID per 10,000 persons aged 15-64 years varied across MSAs from 31 to 345 in 1992 (median 104.4) to 34 to 324 in 2007 (median 91.5). Trend analysis indicates that this rate declined during the early period and then was relatively stable in 2002-2007. Overall prevalence rates for non-Hispanic black PWID increased in 2005 as compared to other racial/ethnic groups. Hispanic prevalence, in contrast, declined across time. Importantly, results show a worrisome trend in young PWID prevalence since HAART was initiated--the mean prevalence was 90 to 100 per 10,000 youth in 1992-1996, but increased to >120 PWID per 10,000 youth in 2006-2007.

CONCLUSIONS

Overall, PWID rates remained constant since 2002, but increased for two subpopulations: non-Hispanic black PWID and young PWID. Estimates of PWID are important for planning and evaluating public health programs to reduce harm among PWID and for understanding related trends in social and health outcomes.

Metropolitan social environments and pre-HAART/HAART era changes in mortality rates (per 10,000 adult residents) among injection drug users living with AIDS

Background

Among the largest US metropolitan areas, trends in mortality rates for injection drug users (IDUs) with AIDS vary substantially. Ecosocial, risk environment and dialectical theories suggest many metropolitan areas characteristics that might drive this variation. We assess metropolitan area characteristics associated with decline in mortality rates among IDUs living with AIDS (per 10,000 adult MSA residents) after highly active antiretroviral therapy (HAART) was developed.

Methods

This is an ecological cohort study of 86 large US metropolitan areas from 1993–2006. The proportional rate of decline in mortality among IDUs diagnosed with AIDS (as a proportion of adult residents) from 1993–1995 to 2004–2006 was the outcome of interest. This rate of decline was modeled as a function of MSA-level variables suggested by ecosocial, risk environment and dialectical theories. In multiple regression analyses, we used 1993–1995 mortality rates to (partially) control for pre-HAART epidemic history and study how other independent variables affected the outcomes.

Results

In multivariable models, pre-HAART to HAART era increases in ‘hard drug’ arrest rates and higher pre-HAART income inequality were associated with lower relative declines in mortality rates. Pre-HAART per capita health expenditure and drug abuse treatment rates, and pre- to HAART-era increases in HIV counseling and testing rates, were weakly associated with greater decline in AIDS mortality.

Conclusions

Mortality among IDUs living with AIDS might be decreased by reducing metropolitan income inequality, increasing public health expenditures, and perhaps increasing drug abuse treatment and HIV testing services. Given prior evidence that drug-related arrest rates are associated with higher HIV prevalence rates among IDUs and do not seem to decrease IDU population prevalence, changes in laws and policing practices to reduce such arrests while still protecting public order should be considered.

Rapid diagnostic HCV antibody assays

Approximately 4.1 million Americans have been infected with HCV and 45-85% of chronically infected persons are unaware of their status. Rapid anti-HCV assays can assist and expedite the identification of those unaware of their infection. Performance characteristics of pre-market rapid anti-HCV assays (Chembio, MedMira and OraSure) have been evaluated. Their sensitivity (78.9-99.3%) and specificity (80-100%) varied. Future investigations could include evaluation of rapid anti-HCV tests in persons who are coinfected with HCV and HIV, and development of rapid HCV-antigen tests and nucleic acid tests.

Cost effectiveness of screening strategies for early identification of HIV and HCV infection in injection drug users

OBJECTIVE

To estimate the cost, effectiveness, and cost effectiveness of HIV and HCV screening of injection drug users (IDUs) in opioid replacement therapy (ORT).

DESIGN

Dynamic compartmental model of HIV and HCV in a population of IDUs and non-IDUs for a representative U.S. urban center with 2.5 million adults (age 15-59).

METHODS

We considered strategies of screening individuals in ORT for HIV, HCV, or both infections by antibody or antibody and viral RNA testing. We evaluated one-time and repeat screening at intervals from annually to once every 3 months. We calculated the number of HIV and HCV infections, quality-adjusted life years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs).

RESULTS

Adding HIV and HCV viral RNA testing to antibody testing averts 14.8-30.3 HIV and 3.7-7.7 HCV infections in a screened population of 26,100 IDUs entering ORT over 20 years, depending on screening frequency. Screening for HIV antibodies every 6 months costs $30,700/QALY gained. Screening for HIV antibodies and viral RNA every 6 months has an ICER of $65,900/QALY gained. Strategies including HCV testing have ICERs exceeding $100,000/QALY gained unless awareness of HCV-infection status results in a substantial reduction in needle-sharing behavior.

DISCUSSION

Although annual screening for antibodies to HIV and HCV is modestly cost effective compared to no screening, more frequent screening for HIV provides additional benefit at less cost. Screening individuals in ORT every 3-6 months for HIV infection using both antibody and viral RNA technologies and initiating ART for acute HIV infection appears cost effective.

A complex systems approach to evaluate HIV prevention in metropolitan areas: preliminary implications for combination intervention strategies

BACKGROUND

HIV transmission among injecting and non-injecting drug users (IDU, NIDU) is a significant public health problem. Continuing propagation in endemic settings and emerging regional outbreaks have indicated the need for comprehensive and coordinated HIV prevention. We describe the development of a conceptual framework and calibration of an agent-based model (ABM) to examine how combinations of interventions may reduce and potentially eliminate HIV transmission among drug-using populations.

METHODOLOGY/PRINCIPAL FINDINGS

A multidisciplinary team of researchers from epidemiology, sociology, geography, and mathematics developed a conceptual framework based on prior ethnographic and epidemiologic research. An ABM was constructed and calibrated through an iterative design and verification process. In the model, "agents" represent IDU, NIDU, and non-drug users who interact with each other and within risk networks, engaging in sexual and, for IDUs, injection-related risk behavior over time. Agents also interact with simulated HIV prevention interventions (e.g., syringe exchange programs, substance abuse treatment, HIV testing) and initiate antiretroviral treatment (ART) in a stochastic manner. The model was constructed to represent the New York metropolitan statistical area (MSA) population, and calibrated by comparing output trajectories for various outcomes (e.g., IDU/NIDU prevalence, HIV prevalence and incidence) against previously validated MSA-level data. The model closely approximated HIV trajectories in IDU and NIDU observed in New York City between 1992 and 2002, including a linear decrease in HIV prevalence among IDUs. Exploratory results are consistent with empirical studies demonstrating that the effectiveness of a combination of interventions, including syringe exchange expansion and ART provision, dramatically reduced HIV prevalence among IDUs during this time period.

CONCLUSIONS/SIGNIFICANCE

Complex systems models of adaptive HIV transmission dynamics can be used to identify potential collective benefits of hypothetical combination prevention interventions. Future work will seek to inform novel strategies that may lead to more effective and equitable HIV prevention strategies for drug-using populations.

A comparison of syringe disposal practices among injection drug users in a city with versus a city without needle and syringe programs

BACKGROUND

The United States (U.S.) approved use of federal funds for needle and syringe programs (NSPs) in December 2009. This study compares syringe disposal practices in a U.S. city with NSPs to a U.S. city without NSPs by examining the prevalence of improperly discarded syringes in public places and the self-reported syringe disposal practices of injection drug users (IDUs) in the two cities.

METHODS

We conducted visual inspection walkthroughs in a random sample of the top-quartile of drug-affected neighborhoods in San Francisco, California (a city with NSPs) and Miami, Florida (a city without NSPs). We also conducted quantitative interviews with adult IDUs in San Francisco (N=602) and Miami (N=448).

RESULTS

In the visual inspections, we found 44 syringes/1000 census blocks in San Francisco, and 371 syringes/1000 census blocks in Miami. Survey results showed that in San Francisco 13% of syringes IDUs reported using in the 30 days preceding the study interviews were disposed of improperly versus 95% of syringes by IDUs in Miami. In multivariable logistic regression analysis, IDUs in Miami had over 34 times the adjusted odds of public syringe disposal relative to IDUs in San Francisco (adjusted odds ratio=34.2, 95% CI=21.92, 53.47).

CONCLUSIONS

We found eight-fold more improperly disposed syringes on walkthroughs in the city without NSPs compared to the city with NSPs, which was corroborated by survey data. NSPs may help IDUs dispose of their syringes safely in cities with large numbers of IDUs.

Field-based performance of three pre-market rapid hepatitis C virus antibody assays in STAHR (Study to Assess Hepatitis C Risk) among young adults who inject drugs in San Diego, CA

BACKGROUND

Approximately 4.1 million Americans are estimated to have been infected with hepatitis C virus (HCV), 45-85% of whom are unaware of their infection. Persons who inject drugs (PWID) account for 55.8% of all persons with HCV antibody (anti-HCV) in the U.S. PWID have limited access to healthcare and are infrequently tested for anti-HCV using conventional laboratory assays.

OBJECTIVE

To evaluate performance characteristics (sensitivity and specificity) of three, pre-market rapid point-of-care tests (one oral fluid and two finger-stick assays) from two manufacturers (Chembio and MedMira) in settings providing services to young adult PWID in San Diego, CA.

STUDY DESIGN

Behavioral risk assessment surveys and testing for HCV were conducted among persons who reported injection drug use (IDU) within the past 6 months as part of the Study to Assess Hepatitis C Risk (STAHR) among PWID aged 18-40 years in 2009-2010. Sensitivity and specificity of the rapid anti-HCV assays were evaluated among STAHR participants, using two commonly used testing algorithms.

RESULTS

Variability in sensitivity (76.6-97.1%) and specificity (99.0-100.0%) was found across assays. The highest sensitivity achieved for the Chembio finger-stick blood, Chembio oral fluid and MedMira finger-stick blood tests was 97.1%, 85.4% and 80.0% respectively; the highest specificity was 99.0%, 100.0% and 100.0%, respectively. In multivariate analysis false negative anti-HCV results were associated with female sex for the MedMira blood assay.

CONCLUSIONS

Sensitive anti-HCV rapid assays are appropriate and feasible for high-prevalence, high-risk populations such as young PWID.

Use of Medicaid data to explore community characteristics associated with HIV prevalence among beneficiaries with schizophrenia

OBJECTIVES

People with severe mental illness (SMI) may be at increased risk for several adverse health conditions, including HIV/AIDS. This disproportionate disease burden has been studied primarily at the individual rather than community level, in part due to the rarity of data sources linking individual information on medical and mental health characteristics with community-level data. We demonstrated the potential of Medicaid data to address this gap.

METHODS

We analyzed data on Medicaid beneficiaries with schizophrenia from eight states that account for 66% of cumulative AIDS cases nationally.

RESULTS

Across 44 metropolitan statistical areas (MSAs), the treated prevalence of HIV among adult Medicaid beneficiaries diagnosed with schizophrenia was 1.56% (standard deviation = 1.31%). To explore possible causes of variation, we linked claims files with a range of MSA social and contextual variables including local AIDS prevalence rates, area-based economic measures, crime rates, substance abuse treatment resources, and estimates of injection drug users (IDUs) and HIV infection among IDUs, which strongly predicted community infection rates among people with schizophrenia.

CONCLUSIONS

Effective strategies for HIV prevention among people with SMI may include targeting prevention efforts to areas where risk is greatest; examining social network links between IDU and SMI groups; and implementing harm reduction, drug treatment, and other interventions to reduce HIV spread among IDUs. Our findings also suggest the need for research on HIV among people with SMI that examines geographical variation and demonstrates the potential use of health-care claims data to provide epidemiologic insights into small-area variations and trends in physical health among those with SMI.

Linkage to care for HIV-infected heterosexual men in the United States

In the United States, the human immunodeficiency virus (HIV) epidemic among heterosexual men disproportionately affects individuals involved with the criminal justice system, injection drug and other substance users, and racial and ethnic minorities. These overlapping populations confront similar social and structural disparities that contribute to HIV risk and limit access to HIV testing, treatment, and care. In this review, we discuss barriers to linkage to comprehensive HIV care for specific subpopulations of heterosexual men and examine approaches for enhancing linkage to care for this diverse population.

Health and oral health care needs and health care-seeking behavior among homeless injection drug users in San Francisco

Few existing studies have examined health and oral health needs and treatment-seeking behavior among the homeless and injection drug users (IDUs). This paper describes the prevalence and correlates of health and oral health care needs and treatment-seeking behaviors in homeless IDUs recruited in San Francisco, California, from 2003 to 2005 (N = 340). We examined sociodemographic characteristics, drug use patterns, HIV status via oral fluid testing, physical health using the Short Form 12 Physical Component Score, self-reported needs for physical and oral health care, and the self-reported frequency of seeking medical and oral health care. The sample had a lower health status as compared to the general population and reported a frequent need for physical and oral health care. In bivariate analysis, being in methadone treatment was associated with care-seeking behavior. In addition, being enrolled in Medi-Cal, California's state Medicaid program, was associated with greater odds of seeking physical and oral health care. Methamphetamine use was not associated with higher odds of needing oral health care as compared to people who reported using other illicit drugs. Homeless IDUs in San Francisco have a large burden of unmet health and oral health needs. Recent cuts in Medi-Cal's adult dental coverage may result in a greater burden of oral health care which will need to be provided by emergency departments and neighborhood dental clinics.

Increased plasmacytoid dendritic cell maturation and natural killer cell activation in HIV-1 exposed, uninfected intravenous drug users

BACKGROUND

Increased natural killer (NK) activation has been associated with resistance to HIV-1 infection in several cohorts of HIV-1 exposed, uninfected individuals. Inheritance of protective NK receptor alleles (KIR3DS1 and KIR3DL1) has also been observed in a subset of HIV-1 exposed, uninfected individuals. However, the exact mechanism contributing to NK activation in HIV-1 exposed, uninfected intravenous drug users (EU-IDU) remains to be elucidated.

OBJECTIVE

We investigated the role of both host genotype and pathogen-induced dendritic cell modulation of NK activation during high-risk activity in a cohort of 15 EU-IDU individuals and 15 control, uninfected donors from Philadelphia.

DESIGN

We assessed the activation status of NK cells and dendritic cells by flow cytometry and utilized functional assays of NK-DC cross-talk to characterize the innate immune compartment in EU-IDU individuals.

RESULTS

As previously reported, NK cell activation (CD69) and/or degranulation (CD107a) was significantly increased in EU-IDU individuals compared with control uninfected donors (P = 0.0056, n = 13). Genotypic analysis indicated that the frequency of protective KIR (KIR3DS1) and HLA-Bw4*80I ligands was not enriched in our cohort of EU-IDU individuals. Rather, plasmacytoid dendritic cells (PDC) from EU-IDU exhibited heightened maturation (CD83) compared with control uninfected donors (P = 0.0011, n = 12). When stimulated in vitro, both PDCs and NK cells from EU-IDU individuals maintained strong effector cell function and did not exhibit signs of exhaustion.

CONCLUSION

Increased maturation of PDCs is associated with heightened NK activation in EU-IDU individuals suggesting that both members of the innate compartment may contribute to resistance from HIV-1 infection in EU-IDU.

Group sex events amongst non-gay drug users: an understudied risk environment

This article discusses relevant literature on group sex events--defined as events at which some people have sex with more than one partner--as risk environments, with a particular focus on group sex events where people who take drugs by non-injection routes of administration participate and where the event is not primarily LGBT-identified, at a "classic" crack house, nor in a brothel. It also briefly presents some findings from a small ethnography of such events. Group sex participation by people who take drugs by non-injection routes of administration seems to be widespread. It involves both behavioural and network risk for HIV and STI infection, including documented high-risk behaviour and sexual mixing of STI- and HIV-infected people with those who are uninfected. Indeed several HIV and STI outbreaks have been documented as based on such group sex events. Further, group sex events often serve as potential bridge environments that may allow infections to pass from members of one high-risk-behavioural category to another, and to branch out through these people's sexual and/or injection networks to other members of the local community. The ethnographic data presented here suggest a serious possibility of "third party transmission" of infectious agents between people who do not have sex with each other. This can occur even when condoms are consistently used since condoms and sex toys are sometimes used with different people without being removed or cleaned, and since fingers and mouths come into contact with mucosal surfaces of other members of the same or opposite sex. In addition to being risk environments, many of these group sex events are venues where risk-reducing norms, activities and roles are present--which lays the basis for harm reduction interventions. Research in more geographical locations is needed so we can better understand risks associated with group sex events in which drug users participate--and, in particular, how both participants and others can intervene effectively to reduce the risks posed to participants and non-participants by these group sex events. Such interventions are needed and should be developed.

Estimated HIV incidence, prevalence, and mortality rates among racial/ethnic populations of men who have sex with men, Florida

BACKGROUND

Population-based HIV incidence, prevalence, and mortality rates among men who have sex with men (MSM) have been unavailable, limiting assessment of racial/ethnic disparities and epidemic dynamics.

METHODS

Using estimated numbers of MSM aged >or=18 years by race/ethnicity as denominators, from models in our prior work, we estimated MSM HIV prevalence and mortality rates for 2006-2007 and HIV incidence rates for 2006 in Florida.

RESULTS

Overall, the estimated MSM HIV prevalence rates per 100,000 MSM were 7354.8 (2006), and 7758.3 (2007). With white MSM as the referent, MSM HIV prevalence rate ratios (RRs) equaled 3.7 for blacks in 2006 and 3.6 in 2007 and 1.7 for Hispanics in both years (all P < 0.001). Among all MSM with HIV, the mortality rates were 199.8 (2006) and 188.4 (2007), with RRs of 5.4 for blacks in 2006 and 4.9 in 2007, and 1.6 for Hispanics in 2006 and 1.4 in 2007 (all P < 0.001). In 2006, the estimated HIV incidence rate among all MSM was 656.1 per 100,000 MSM, with RRs of 5.5 (blacks) and 2.0 (Hispanics) (both P < 0.001). A sensitivity analysis indicated that error due to misclassification of minority MSM as males who are not MSM lowered rates and RRs for all the 3 indicators but racial/ethnic disparities persisted (all P < 0.001).

CONCLUSIONS

The impact of HIV by each measure was greater on black and Hispanic MSM than on white MSM. Quantifying estimates of HIV incidence, HIV prevalence, and mortality rates among MSM with HIV informs HIV surveillance, prevention, treatment, resource allocation, and community mobilization.

Attitudes toward methadone among out-of-treatment minority injection drug users: implications for health disparities

Injection drug use (IDU) continues to be a significant public health issue in the U.S. and internationally, and there is evidence to suggest that the burden of injection drug use and associated morbidity and mortality falls disproportionately on minority communities. IDU is responsible for a significant portion of new and existing HIV/AIDS cases in many parts of the world. In the U.S., the prevalence of HIV and hepatitis C virus is higher among populations of African-American and Latino injection drug users (IDUs) than among white IDUs. Methadone maintenance therapy (MMT) has been demonstrated to effectively reduce opiate use, HIV risk behaviors and transmission, general mortality and criminal behavior, but opiate-dependent minorities are less likely to access MMT than whites. A better understanding of the obstacles minority IDUs face accessing treatment is needed to engage racial and ethnic disparities in IDU as well as drug-related morbidity and mortality. In this study, we explore knowledge, attitudes and beliefs about methadone among 53 out-of-treatment Latino and African-American IDUs in Providence, RI. Our findings suggest that negative perceptions of methadone persist among racial and ethnic minority IDUs in Providence, including beliefs that methadone is detrimental to health and that people should attempt to discontinue methadone treatment. Additional potential obstacles to entering methadone therapy include cost and the difficulty of regularly attending a methadone clinic as well as the belief that an individual on MMT is not abstinent from drugs. Substance use researchers and treatment professionals should engage minority communities, particularly Latino communities, in order to better understand the treatment needs of a diverse population, develop culturally appropriate MMT programs, and raise awareness of the benefits of MMT.