Stroke and Systemic Thromboembolism Prevention in People Living With Human Immunodeficiency Virus With Atrial Fibrillation: A Review of Its Implications for Clinical Practice

In the last few decades, types of diseases affecting people living with human immunodeficiency virus (PLHIV) have shifted as the population ages, with cardiovascular disease becoming a leading cause of death in this population. Atrial fibrillation (AF) is an increasingly common arrhythmia both in the general population and in PLHIV, with an estimated prevalence of 2% to 3% among PLHIV. Prevention of stroke and systemic thromboembolism (SSE) with antithrombotic therapy is a cornerstone of AF treatment and substantially decreases AF-related morbidity and mortality. Although updated guidelines extensively discuss this issue, they do not address the peculiarities of PLHIV. The role of human immunodeficiency virus (HIV) infection as an independent factor for SSE in individuals with AF and whether the presence of HIV should alter the threshold for SSE thromboprophylaxis are unknown. Nevertheless, a growing body of evidence describes the increasing burden of comorbidities such as hypertension and stroke in PLHIV, which predispose them to AF and SSE. In the absence of HIV-specific AF guidelines, PLHIV with AF should be comprehensively assessed for their risk of SSE and bleeding using commonly available scores despite them having been primarily validated in the non-HIV population. Both vitamin K antagonists and direct oral anticoagulants can be used in PLHIV. Addressing HIV-related comorbidities and potential drug-drug interactions with antiretrovirals is crucial to prevent SSE and reduce adverse reactions of oral anticoagulants. This review summarizes the current guidelines for SSE prevention in patients with AF and describes key considerations for their implementation among PLHIV receiving antiretroviral therapy.

Decreased telomere length in the small airway epithelium suggests accelerated aging in the lungs of persons living with human immunodeficiency virus (HIV)

Human immunodeficiency virus (HIV) infection is associated with an increased risk of chronic obstructive pulmonary disease (COPD) independent of cigarette smoke exposure. Previous studies have demonstrated that decreased peripheral leukocyte telomere length is associated with HIV, suggesting an accelerated aging phenomenon. We demonstrate that this process of telomere shortening also occurs in the lungs, with significant decreases in telomere length observed in small airway epithelial cells collected during bronchoscopy. Molecular evidence of accelerated aging in the small airway epithelium of persons living with HIV may be one clue into the predisposition for chronic lung disease observed in this population.

Dose-response relationship between functional pain interference and nonmedical analgesic use: Findings from a nationally representative Canadian survey

Background

Despite the epidemic of nonmedical analgesic use (NMAU) in North America, there is a scarcity of research quantifying the effect of pain on NMAU.

Aims

This study sought to investigate the relationship between NMAU and functional pain interference, defined as the perceived level of interference in performing activities of daily living due to pain, in a population-based sample of the general Canadian population.

Methods

Data from the 2012 Canadian Community Health Survey (CCHS)–Mental Health, a nationally representative cross-sectional survey, were used to conduct bivariable and multivariable logistic regression analyses.

Results

The weighted prevalences of pain and NMAU were 20.6% and 6.6%, respectively. After adjusting for age, sex, education, culture/race, and chronic mental health diagnosis, a dose–response relationship was observed between higher functional pain interference and increased odds of NMAU, ranging from 1.61 (95% confidence interval [CI], 1.22–2.12) to 2.98 (95% CI, 2.21–4.01) from the lowest to the highest levels of functional pain interference. Elevated odds of NMAU were also observed among younger respondents aged 20–29 years and 15–19 years, respondents with a chronic mental illness diagnosis, and males. Secondary analyses revealed that the dose–response relationship between greater function pain interference and increased odds of NMAU persisted within subgroups with and without mental illness, as well as within subgroups aged 40 to 69.

Conclusions

These findings highlight the potential role of pain on increasing NMAU and the need for targeted strategies to reduce harms of NMAU among high-risk subgroups such as young adults.

HIV and the criminalisation of drug use among people who inject drugs: a systematic review

BACKGROUND

Mounting evidence suggests that laws and policies prohibiting illegal drug use could have a central role in shaping health outcomes among people who inject drugs (PWID). To date, no systematic review has characterised the influence of laws and legal frameworks prohibiting drug use on HIV prevention and treatment.

METHODS

Consistent with PRISMA guidelines, we did a systematic review of peer-reviewed scientific evidence describing the association between criminalisation of drug use and HIV prevention and treatment-related outcomes among PWID. We searched MEDLINE, Embase, SCOPUS, PsycINFO, Sociological Abstracts, CINAHL, Web of Science, and other sources. To be included in our review, a study had to meet the following eligibility criteria: be published in a peer-reviewed journal or presented as a peer-reviewed abstract at a scientific conference; examine, through any study design, the association between an a-priori set of indicators related to the criminalisation of drugs and HIV prevention or treatment among PWID; provide sufficient details on the methods followed to allow critical assessment of quality; be published or presented between Jan 1, 2006, and Dec 31, 2014; and be published in the English language.

FINDINGS

We identified 106 eligible studies comprising 29 longitudinal, 49 cross-sectional, 22 qualitative, two mixed methods, four mathematical modelling studies, and no randomised controlled trials. 120 criminalisation indicators were identified (range 1-3 per study) and 150 HIV indicators were identified (1-5 per study). The most common criminalisation indicators were incarceration (n=38) and street-level policing (n=39), while the most frequent HIV prevention and treatment indicators were syringe sharing (n=35) and prevalence of HIV infection among PWID (n=28). Among the 106 studies included in this review, 85 (80%) suggested that drug criminalisation has a negative effect on HIV prevention and treatment, 10 (9%) suggested no association, five (5%) suggested a beneficial effect, one (1%) suggested both beneficial and negative effects, and five (5%) suggested both null and negative effects.

INTERPRETATION

These data confirm that criminalisation of drug use has a negative effect on HIV prevention and treatment. Our results provide an objective evidence base to support numerous international policy initiatives to reform legal and policy frameworks criminalising drug use.

FUNDING

Canadian Institutes of Health Research and US National Institutes of Health.

The Hotel Study-Clinical and Health Service Effectiveness in a Cohort of Homeless or Marginally Housed Persons

OBJECTIVE

The Hotel Study was initiated in Vancouver's Downtown East Side (DTES) neighborhood to investigate multimorbidity in homeless or marginally housed people. We evaluated the clinical effectiveness of existing, illness-specific treatment strategies and assessed the effectiveness of health care delivery for multimorbid illnesses.

METHOD

For context, we mapped the housing locations of patients presenting for 552,062 visits to the catchment hospital emergency department (2005-2013). Aggregate data on 22,519 apprehensions of mentally ill people were provided by the Vancouver Police Department (2009-2015). The primary strategy was a longitudinal cohort study of 375 people living in the DTES (2008-2015). We analysed mortality and evaluated the clinical and health service delivery effectiveness for infection with human immunodeficiency virus or hepatitis C virus, opioid dependence, and psychosis.

RESULTS

Mapping confirmed the association between poverty and greater number of emergency visits related to substance use and mental illness. The annual change in police apprehensions did not differ between the DTES and other policing districts. During 1581 person-years of cohort observation, the standardized mortality ratio was 8.43 (95% confidence interval, 6.19 to 11.50). Physician visits were common (84.3% of participants over 6 months). Clinical treatment effectiveness was highest for HIV/AIDS, intermediate for opioid dependence, and lowest for psychosis. Health service delivery mechanisms provided examples of poor access, poor treatment adherence, and little effect on multimorbid illnesses.

CONCLUSIONS

Clinical effectiveness was variable, and illness-specific service delivery appeared to have little effect on multimorbidity. New models of care may need to be implemented.

The bronchial epithelial cell bacterial microbiome and host response in patients infected with human immunodeficiency virus

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) is an important comorbidity in patients living with human immunodeficiency virus (HIV). Previous bacterial microbiome studies have shown increased abundance of specific bacterium, like Tropheryma whipplei, and no overall community differences. However, the host response to the lung microbiome is unknown in patients infected with HIV.

METHODS

Two bronchial brush samples were obtained from 21 HIV-infected patients. One brush was used for bacterial microbiome analysis using the Illumina MiSeq^TM platform, while the other was used to evaluate gene expression patterns of the host using the Affymetrix Human Gene ST 2.0 array. Weighted gene co-expression network analysis was used to determine the relationship between the bacterial microbiome and host gene expression response.

RESULTS

The Shannon Diversity was inversely related to only one gene expression module (p = 0.02); whereas evenness correlated with five different modules (p ≤ 0.05). After FDR correction only the Firmicutes phylum was significantly correlated with any modules (FDR < 0.05). These modules were enriched for cilia, transcription regulation, and immune response. Specific operational taxonomic units (OTUs), such as OTU4 (Pasteurellaceae), were able to distinguish HIV patients with and without COPD and severe emphysema.

CONCLUSION

These data support the hypothesis that the bacterial microbiome in HIV lungs is associated with specific host immune responses. Whether or not these responses are also seen in non-HIV infected individuals needs to be addressed in future studies.

A single untimed plasma drug concentration measurement during low-level HIV viremia predicts virologic failure

Suboptimal untimed plasma drug levels (UDL) have been associated with lower rates of virologic suppression and the emergence of drug resistance. Our aim was to evaluate whether UDL among patients with low-level viremia (LLV) while receiving highly active antiretroviral therapy (HAART) can predict subsequent virologic failure (plasma viral load ≥1000 copies/mL) and emergence of resistance. The first documented LLV episode of 328 consenting patients was analysed in terms of drug levels, viral load and resistance, which were monitored while patients were on a consistent HAART regimen. UDL of protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs), were categorized as 'therapeutic' or 'subtherapeutic' based on predefined target trough concentrations. Drug resistance genotype was assessed using the Stanford algorithm. Time to virologic failure was evaluated by Kaplan-Meier analysis and Cox proportional hazards regression. We found 78 of 328 patients (24%) with subtherapeutic drug levels at time of first detectable LLV, while 19% harboured drug-resistant virus. Both subtherapeutic UDL and drug resistance independently increased the risk of subsequent virologic failure (p <0.001 and p 0.04, respectively). In a multivariable model, variables associated with LLV and virologic failure included subtherapeutic UDL, elevated plasma viral load, and drug resistance. Patients with subtherapeutic UDL accumulated further drug resistance faster during follow-up (p 0.03). Together, resistance and UDL variables can explain a higher proportion of virologic failure than either measure alone. Our results support further prospective evaluation of UDL in the management of low-level viremia.

Suicide Attempts and Childhood Maltreatment Among Street Youth: A Prospective Cohort Study

BACKGROUND

Although suicide is a known leading cause of death among street youth, few prospective studies have explored childhood experiences as risk factors for future suicide attempt in this population. We examined the risk of attempted suicide in relation to childhood maltreatment among street youth.

METHODS

From September 2005 to November 2013, data were collected from the At Risk Youth Study (ARYS), a prospective cohort of street youth in Vancouver, Canada. Inclusion criteria were age 14 to 26 years, past-month illicit drug use, and street involvement. Participants completed the Childhood Trauma Questionnaire, an instrument measuring self-reported sexual, physical, and emotional abuse and physical and emotional neglect. Suicide attempts were assessed semiannually. Using Cox regression, we examined the association between the 5 types of maltreatment and suicide attempts.

RESULTS

Of 660 participants, 68.2% were male and 24.6% were Aboriginal. Median age was 21.5 years. The prevalence of moderate to extreme childhood maltreatment ranged from 16.8% (sexual abuse) to 45.2% (emotional abuse). Participants contributed 1841 person-years, with suicide attempts reported by 35 (5.3%) individuals (crude incidence density: 1.9 per 100 person-years; 95% confidence interval [CI]: 1.4-2.6 per 100 person-years). In adjusted analyses, types of maltreatment associated with suicide attempts included physical abuse (adjusted hazard ratio [HR]: 4.47; 95% CI: 2.12-9.42), emotional abuse (adjusted HR: 4.92; 95% CI: 2.11-11.5), and emotional neglect (adjusted HR: 3.08; 95% CI: 1.05-9.03).

CONCLUSIONS

Childhood maltreatment is associated with subsequent risk of suicidal behavior among street youth. Suicide prevention efforts should be targeted toward this marginalized population and delivered from a trauma-informed perspective.

Mortality from treatable illnesses in marginally housed adults: a prospective cohort study

OBJECTIVES

Socially disadvantaged people experience greater risk for illnesses that may contribute to premature death. This study aimed to evaluate the impact of treatable illnesses on mortality among adults living in precarious housing.

DESIGN

A prospective cohort based in a community sample.

SETTING

A socially disadvantaged neighbourhood in Vancouver, Canada.

PARTICIPANTS

Adults (N=371) living in single room occupancy hotels or recruited from the Downtown Community Court and followed for median 3.8 years.

MAIN OUTCOME MEASURES

Participants were assessed for physical and mental illnesses for which treatment is currently available. We compared cohort mortality rates with 2009 Canadian rates. Left-truncated Cox proportional hazards modelling with age as the time scale was used to assess risk factors for earlier mortality.

RESULTS

During 1269 person-years of observation, 31/371 (8%) of participants died. Compared with age-matched and sex-matched Canadians, the standardised mortality ratio was 8.29 (95% CI 5.83 to 11.79). Compared with those that had cleared the virus, active hepatitis C infection was a significant predictor for hepatic fibrosis adjusting for alcohol dependence and age (OR=2.96, CI 1.37 to 7.08). Among participants <55 years of age, psychosis (HR=8.12, CI 1.55 to 42.47) and hepatic fibrosis (HR=13.01, CI 3.56 to 47.57) were associated with earlier mortality. Treatment rates for these illnesses were low (psychosis: 32%, hepatitis C virus: 0%) compared with other common disorders (HIV: 57%, opioid dependence: 61%) in this population.

CONCLUSIONS

Hepatic fibrosis and psychosis are associated with increased mortality in people living in marginal conditions. Timely diagnosis and intervention could reduce the high mortality in marginalised inner city populations.

Effect of low-threshold methadone maintenance therapy for people who inject drugs on HIV incidence in Vancouver, BC, Canada: an observational cohort study

BACKGROUND

HIV infection in people who inject drugs (PWID) is an international public health concern. We aimed to assess the effect of methadone maintenance therapy on HIV incidence in PWID in Vancouver, BC, Canada, where methadone is widely available through family physicians' offices and dispensed by community pharmacies.

METHODS

Data were derived from the Vancouver Injection Drug Users Study (VIDUS), a prospective cohort of PWID in Vancouver. Individuals were eligible to enrol in VIDUS if they had injected illicit drugs at least once in the previous month and lived in the Greater Vancouver region. Participants responded to an interviewer-administered questionnaire and provided blood samples at enrolment and follow-up visits every 6 months. We estimated time to HIV seroconversion with Kaplan-Meier methods and used Cox proportional hazards methods to assess associations between methadone use and time to seroconversion.

FINDINGS

1639 HIV-negative individuals were recruited between May 1, 1996, and May 31, 2013. Of these individuals, 138 had HIV seroconversion during a median of 75·5 months (IQR 33·4-115·3) of follow-up. In multivariate Cox regression analyses, methadone maintenance therapy remained independently associated with a reduced hazard of HIV infection after adjustment for sociodemographic characteristics and drug use patterns (adjusted relative hazard 0·64, 95% CI 0·41-0·98).

INTERPRETATION

Methadone maintenance therapy for PWID made available through primary care physicians and community pharmacies can help to achieve public health goals such as reducing the spread of HIV.

FUNDING

US National Institutes of Health, Canada Research Chair, Canadian Institutes of Health Research.

Successes and gaps in uptake of regular, voluntary HIV testing for hidden street- and off-street sex workers in Vancouver, Canada

Despite evidence globally of the heavy HIV burden among sex workers (SWs) as well as other poor health outcomes, including violence, SWs are often excluded from accessing voluntary, confidential and non-coercive health services, including HIV prevention, treatment, care and support. This study therefore assessed the prevalence and association with regular HIV testing among street- and off-street SWs in Vancouver, Canada. Cross-sectional baseline data were used from a longitudinal cohort known as "An Evaluation of Sex Worker's Health Access" (AESHA; January 2010-July 2012). This cohort included youth and adult SWs (aged 14+ years). We used multivariable logistic regression to assess the relationship between explanatory variables and having a recent HIV test (in the last year). Of the 435 seronegative SWs included, 67.1% reported having a recent HIV test. In multivariable logistic regression analysis, having a recent HIV test remained significantly independently associated with elevated odds of inconsistent condom use with clients [adjusted (multivariable) odds ratios, AOR: 2.59, 95% confidence intervals [95% CIs]: 1.17-5.78], injecting drugs (AOR: 2.33, 95% CIs: 1.17-4.18) and contact with a mobile HIV prevention programme (AOR: 1.76, 95% CIs: 1.09-2.84) within the last six months. Reduced odds of having a recent HIV test was also significantly associated with being a migrant/new immigrant to Canada (AOR: 0.33, 95% CIs: 0.19-0.56) and having a language barrier to health care access (AOR: 0.26, 95% CIs: 0.09-0.73). Our results highlight successes of reaching SWs at high risk of HIV through drug and sexual pathways. To maximize the effectiveness of including HIV testing as part of comprehensive HIV prevention and care to SWs, increased mobile outreach and safer-environment interventions that facilitate access to voluntary, confidential and non-coercive HIV testing remain a critical priority, in addition to culturally safe services with language support.

Prescription opioid injection and risk of hepatitis C in relation to traditional drugs of misuse in a prospective cohort of street youth

OBJECTIVE

Despite dramatic increases in the misuse of prescription opioids, the extent to which their intravenous injection places drug users at risk of acquiring hepatitis C virus (HCV) remains unclear. We sought to compare risk of HCV acquisition from injection of prescription opioids to that from other street drugs among high-risk street youth.

DESIGN

Prospective cohort study.

SETTING

Vancouver, British Columbia, Canada from September 2005 to November 2011.

PARTICIPANTS

The At-Risk Youth Study (ARYS) is a prospective cohort of drug-using adolescents and young adults aged 14-26 years. Participants were recruited through street-based outreach and snowball sampling.

PRIMARY OUTCOME MEASURE

HCV antibody seroconversion, measured every 6 months during follow-up. Risk for seroconversion from injection of prescription opioids was compared with injection of other street drugs of misuse, including heroin, cocaine or crystal methamphetamine, using Cox proportional hazards regression controlling for age, gender and syringe sharing.

RESULTS

Baseline HCV seropositivity was 10.6%. Among 512 HCV-seronegative youth contributing 860.2 person-years of follow-up, 56 (10.9%) seroconverted, resulting in an incidence density of 6.5/100 person-years. In bivariate analyses, prescription opioid injection (HR=3.48; 95% CI 1.57 to 7.70) predicted HCV seroconversion. However, in multivariate modelling, only injection of heroin (adjusted HR=4.56; 95% CI 2.39 to 8.70), cocaine (adjusted HR=1.88; 95% CI 1.00 to 3.54) and crystal methamphetamine (adjusted HR=2.91; 95% CI 1.57 to 5.38) remained independently associated with HCV seroconversion, whereas injection of prescription opioids did not (adjusted HR=0.94; 95% CI 0.40 to 2.21).

CONCLUSIONS

Although misuse of prescription opioids is on the rise, traditional street drugs still posed the greatest threat of HCV transmission in this setting. Nonetheless, the high prevalence and incidence of HCV among Canadian street youth underscore the need for evidence-based drug prevention, treatment and harm reduction interventions targeting this vulnerable population.

Criminalisation of clients: reproducing vulnerabilities for violence and poor health among street-based sex workers in Canada-a qualitative study

OBJECTIVES

To explore how criminalisation and policing of sex buyers (clients) rather than sex workers shapes sex workers' working conditions and sexual transactions including risk of violence and HIV/sexually transmitted infections (STIs).

DESIGN

Qualitative and ethnographic study triangulated with sex work-related violence prevalence data and publicly available police statistics.

SETTING

Vancouver, Canada, provides a unique opportunity to evaluate the impact of policies that criminalise clients as the local police department adopted a sex work enforcement policy in January 2013 that prioritises sex workers' safety over arrest, while continuing to target clients.

PARTICIPANTS

26 cisgender and 5 transgender women who were street-based sex workers (n=31) participated in semistructured interviews about their working conditions. All had exchanged sex for money in the previous 30 days in Vancouver.

OUTCOME MEASURES

Thematic analysis of interview transcripts and ethnographic field notes focused on how police enforcement of clients shaped sex workers' working conditions and sexual transactions, including risk of violence and HIV/STIs, over an 11-month period postpolicy implementation (January-November 2013).

RESULTS

Sex workers' narratives and ethnographic observations indicated that while police sustained a high level of visibility, they eased charging or arresting sex workers and showed increased concern for their safety. However, participants' accounts and police statistics indicated continued police enforcement of clients. This profoundly impacted the safety strategies sex workers employed. Sex workers continued to mistrust police, had to rush screening clients and were displaced to outlying areas with increased risks of violence, including being forced to engage in unprotected sex.

CONCLUSIONS

These findings suggest that criminalisation and policing strategies that target clients reproduce the harms created by the criminalisation of sex work, in particular, vulnerability to violence and HIV/STIs. The current findings support decriminalisation of sex work to ensure work conditions that support the health and safety of sex workers in Canada and globally.

Tuberculosis in HIV-infected persons in British Columbia during the HAART era

OBJECTIVE

Prior to the introduction of highly active antiretroviral therapy (HAART), active tuberculosis (TB) was a major contributor to HIV-related morbidity and mortality in Canada and other low-incidence regions. We performed this study to examine TB incidence, clinical manifestations and screening uptake in HIV-infected TB patients during the era of HAART therapy.

METHODS

We performed a retrospective study on all HIV-infected TB patients in British Columbia over a 10-year period (2003-2012). Demographic and clinical characteristics were extracted along with screening and treatment outcomes. Trends in provincial TB incidence, HIV testing and HAART prevalence were also examined.

RESULTS

In total, 2,839 TB cases were identified in BC during this period, including 129 HIV-infected TB patients. Surprisingly, only 64 HIV-infected TB patients (50%) had a documented screening tuberculin skin test (TST) prior to TB diagnosis. Of the 39 HIV-infected TB patients with prior TST positivity, 38 (97.4%) had not completed a course of isoniazid preventive therapy. TB incidence decreased significantly in the HIV-infected population of BC over the study period, from 1.9 to 0.5 TB cases per 1,000 HIV-infected individuals (p<0.001).

CONCLUSION

The incidence of HIV-TB decreased significantly over the past decade despite suboptimal latent TB infection screening and prevention practices. This decrease in TB incidence is likely attributable to the increased uptake of HAART. Consideration should be given to intensifying prevention efforts to accelerate TB elimination in HIV-infected populations in low-incidence regions.

The determinants of poor respiratory health status in adults living with human immunodeficiency virus infection

The increased longevity afforded by combination antiretroviral therapy in developed countries has led to an increased concern regarding senescence-related diseases in patients with human immunodeficiency virus (HIV) infection. Previous epidemiologic analyses have demonstrated an increased risk of chronic obstructive pulmonary disease, as well as a significant burden of respiratory symptoms in HIV-infected patients. We performed the St. George's Respiratory Questionnaire (SGRQ) in 199 HIV-positive men, and determined the predominant factors contributing to poor respiratory-related health status. In univariate analyses, worse SGRQ scores were associated with respiratory-related variables such as greater smoking pack-year history (p=0.028), lower forced expiratory volume in 1 second (FEV1) (p<0.001), and worse emphysema severity as quantified by computed tomographic imaging (p=0.017). In addition, HIV-specific variables, such as a history of plasma viral load >100,000 copies/mL (p=0.043), lower nadir CD4 cell count (p=0.040), and current CD4 cell count ≤350 cells/μL (p=0.005), as well as elevated levels of inflammatory markers, specifically plasma interleukin (IL)-6 (p=0.002) and alpha-1 antitrypsin (p=0.005) were also associated with worse SGRQ scores. In a multiple regression model, FEV1, current CD4 count ≤350 cells/μL, and IL-6 levels remained significant contributors to reduced respiratory-related health status. HIV disease activity as measured by HIV-related immunosuppression in conjunction with the triggering of key inflammatory pathways may be important determinants of worse respiratory health status among HIV-infected individuals. Limitations of this analysis include the absence of available echocardiograms, diffusion capacity and lung volume testing, and an all-male cohort due to the demographics of the clinic population.

A comparison of computational models with and without genotyping for prediction of response to second-line HIV therapy

OBJECTIVES

We compared the use of computational models developed with and without HIV genotype vs. genotyping itself to predict effective regimens for patients experiencing first-line virological failure.

METHODS

Two sets of models predicted virological response for 99 three-drug regimens for patients on a failing regimen of two nucleoside/nucleotide reverse transcriptase inhibitors and one nonnucleoside reverse transcriptase inhibitor in the Second-Line study. One set used viral load, CD4 count, genotype, plus treatment history and time to follow-up to make its predictions; the second set did not include genotype. Genotypic sensitivity scores were derived and the ranking of the alternative regimens compared with those of the models. The accuracy of the models and that of genotyping as predictors of the virological responses to second-line regimens were compared.

RESULTS

The rankings of alternative regimens by the two sets of models were significantly correlated in 60-69% of cases, and the rankings by the models that use a genotype and genotyping itself were significantly correlated in 60% of cases. The two sets of models identified alternative regimens that were predicted to be effective in 97% and 100% of cases, respectively. The area under the receiver-operating curve was 0.72 and 0.74 for the two sets of models, respectively, and significantly lower at 0.55 for genotyping.

CONCLUSIONS

The two sets of models performed comparably well and significantly outperformed genotyping as predictors of response. The models identified alternative regimens predicted to be effective in almost all cases. It is encouraging that models that do not require a genotype were able to predict responses to common second-line therapies in settings where genotyping is unavailable.

The hotel study: multimorbidity in a community sample living in marginal housing

OBJECTIVE

The health of people living in marginal housing is not well characterized, particularly from the perspective of multimorbid illness. The authors investigated this population in a community sample.

METHOD

A prospective community sample (N=293) of adults living in single-room occupancy hotels was followed for a median of 23.7 months. Assessment included psychiatric and neurological evaluation, multimodal MRI, and viral testing.

RESULTS

Previous homelessness was described in 66.6% of participants. Fifteen deaths occurred during 552 person-years of follow-up. The standardized mortality ratio was 4.83 (95% CI=2.91-8.01). Substance dependence was ubiquitous (95.2%), with 61.7% injection drug use. Psychosis was the most common mental illness (47.4%). A neurological disorder was present in 45.8% of participants, with definite MRI findings in 28.0%. HIV serology was positive in 18.4% of participants, and hepatitis C virus serology in 70.3%. The median number of multimorbid illnesses (from a list of 12) was three. Burden of multimorbidity was significantly correlated with lower role functioning score. Comorbid addiction or physical illness significantly decreased the likelihood of treatment for psychosis but not the likelihood of treatment for opioid dependence or HIV disease. Participants who died during follow-up appeared to have profiles of multimorbidity similar to those of the overall sample.

CONCLUSIONS

This marginally housed cohort had greater than expected mortality and high levels of multimorbidity with adverse associations with role function and likelihood of treatment for psychosis. These findings may guide the development of effective health care delivery in the setting of marginal housing.

Epidemic of lung cancer in patients with HIV infection

The survival of patients with HIV infection has improved dramatically over the past 20 years, largely owing to a significant reduction in opportunistic infections and AIDs-defining malignancies, such as lymphoma and Kaposi sarcoma. However, with improved survival, patients with HIV are experiencing morbidity and mortality from other (non-AIDs-defining) complications, such as solid organ malignancies. Of these, the leading cause of mortality in the HIV-infected population is lung cancer, accounting for nearly 30% of all cancer deaths and 10% of all non-HIV-related deaths. Importantly, the average age of onset of lung cancer in the HIV-infected population is 25 to 30 years earlier than that in the general population and at lower exposure to cigarette smoke. This article provides an overview of the epidemiology of lung cancer in the HIV-infected population and discusses some of the important risk factors and pathways that may enhance the risk of lung cancer in this population.

Computational models can predict response to HIV therapy without a genotype and may reduce treatment failure in different resource-limited settings

OBJECTIVES

Genotypic HIV drug-resistance testing is typically 60%-65% predictive of response to combination antiretroviral therapy (ART) and is valuable for guiding treatment changes. Genotyping is unavailable in many resource-limited settings (RLSs). We aimed to develop models that can predict response to ART without a genotype and evaluated their potential as a treatment support tool in RLSs.

METHODS

Random forest models were trained to predict the probability of response to ART (≤400 copies HIV RNA/mL) using the following data from 14 891 treatment change episodes (TCEs) after virological failure, from well-resourced countries: viral load and CD4 count prior to treatment change, treatment history, drugs in the new regimen, time to follow-up and follow-up viral load. Models were assessed by cross-validation during development, with an independent set of 800 cases from well-resourced countries, plus 231 cases from Southern Africa, 206 from India and 375 from Romania. The area under the receiver operating characteristic curve (AUC) was the main outcome measure.

RESULTS

The models achieved an AUC of 0.74-0.81 during cross-validation and 0.76-0.77 with the 800 test TCEs. They achieved AUCs of 0.58-0.65 (Southern Africa), 0.63 (India) and 0.70 (Romania). Models were more accurate for data from the well-resourced countries than for cases from Southern Africa and India (P < 0.001), but not Romania. The models identified alternative, available drug regimens predicted to result in virological response for 94% of virological failures in Southern Africa, 99% of those in India and 93% of those in Romania.

CONCLUSIONS

We developed computational models that predict virological response to ART without a genotype with comparable accuracy to genotyping with rule-based interpretation. These models have the potential to help optimize antiretroviral therapy for patients in RLSs where genotyping is not generally available.

Childhood sexual abuse and risk for initiating injection drug use: a prospective cohort study

OBJECTIVE

This study examined whether childhood sexual abuse predicts initiation of injection drug use in a prospective cohort of youth.

METHOD

From October 2005 to November 2010, data were collected from the At Risk Youth Study (ARYS), a prospective cohort study of street-involved youth in Vancouver, Canada. Inclusion criteria were age 14-26 years, no lifetime drug injection, and non-injection drug use in the month preceding enrollment. Participants were interviewed at baseline and semiannually thereafter. Cox regression was employed to identify risk factors for initiating injection.

RESULTS

Among 395 injection-naïve youth, 81 (20.5%) reported childhood sexual abuse. During a median follow-up of 15.9 months (total follow-up 606.6 person-years), 45 (11.4%) youth initiated injection drug use, resulting in an incidence density of 7.4 per 100 person-years. In univariate analyses, childhood sexual abuse was associated with increased risk of initiating injection (unadjusted hazard ratio [HR], 2.38; 95% confidence interval [CI], 1.29-4.38; p=0.006), an effect that persisted in multivariate analysis despite adjustment for gender, age, aboriginal ancestry and recent non-injection drug use (adjusted HR, 2.71; 95% CI, 1.42-5.20; p=0.003).

CONCLUSION

Childhood sexual abuse places drug users at risk for initiating injection. Addiction treatment programs should incorporate services for survivors of childhood maltreatment.

Ready access to illicit drugs among youth and adult users

BACKGROUND

Current drug-control strategies in Canada focus funding and resources predominantly on drug law enforcement, often at the expense of preventive, treatment, and harm reduction efforts. This study aimed to examine the availability of the most commonly used substances in Vancouver, Canada after the implementation of such strategies.

METHODS

Using data from two large cohorts of drug-using youth and adults in Vancouver from the calendar year 2007, we assessed perceived availability of heroin, crack, cocaine, crystal methamphetamine, and marijuana.

RESULTS

Compared to youth (n= 330), a greater proportion of adults (n= 1,160) reported immediate access (ie, within 10 minutes) to heroin (81.0% vs. 55.9%, p < .001), crack (90.4% vs. 69.3%, p < .001), and cocaine (83.7% vs. 61.1%, p < .001). Conversely, larger proportions of youth reported immediate access to crystal methamphetamine (62.8% vs. 39.4%, p < .001) and marijuana (88.4% vs. 73.2%, p < .001) compared to adult users.

CONCLUSIONS

Regardless of differences in illicit drug availability by age, all drugs are readily accessed in Vancouver despite drug law enforcement efforts. This includes drugs that are frequently injected and place users at risk of human immunodeficiency virus (HIV) infection and transmission of other blood-borne disease.

Young age predicts poor antiretroviral adherence and viral load suppression among injection drug users

Previous studies of adherence to antiretroviral therapy (ART) for HIV among young injection drug users (IDU) have been limited because financial barriers to care disproportionately affect youth, thus confounding results. This study examines adherence among IDU in a unique setting where all medical care is provided free-of-charge. From May 1996 to April 2008, we followed a prospective cohort of 545 HIV-positive IDU of 18 years of age or older in Vancouver, Canada. Using generalized estimating equations (GEE), we studied the association between age and adherence (obtaining ART≥95% of the prescribed time), controlling for potential confounders. Using Cox proportional hazards regression, we also studied the effect of age on time to viral load suppression (<500 copies per milliliter), and examined adherence as a mediating variable. Five hundred forty-five participants were followed for a median of 23.8 months (interquartile range [IQR]=8.5-91.6 months). Odds of adherence were significantly lower among younger IDU (adjusted odds ratio [AOR]=0.76 per 10 years younger; 95% confidence interval [CI], 0.65-0.89). Younger IDU were also less likely to achieve viral load suppression (adjusted hazard ratio [AHR]=0.75 per 10 years younger; 95% CI, 0.64-0.88). Adding adherence to the model eliminated this association with age, supporting the role of adherence as a mediating variable. Despite absence of financial barriers, younger IDU remain less likely to adhere to ART, resulting in inferior viral load suppression. Interventions should carefully address the unique needs of young HIV-positive IDU.

Suicide and history of childhood trauma among street youth

BACKGROUND

Street youth represent a marginalized population marked by early mortality and elevated risk for suicide. It is not known to what extent childhood abuse and neglect predispose to suicide in this difficult-to-study population. This study is among the first to examine the relationship between childhood trauma and subsequent attempted suicide during adolescence and young adulthood among street youth.

METHODS

From October 2005 to November 2007, data were collected for the At Risk Youth Study (ARYS), a cohort of 495 street-recruited youth aged 14-26 in Vancouver, Canada. Self-reported attempted suicide in the preceding six months was examined in relation to childhood abuse and neglect, as measured by the Childhood Trauma Questionnaire (CTQ), using logistic regression.

RESULTS

Overall, 46 (9.3%) youth reported a suicide attempt during the preceding six months. Childhood physical and sexual abuse were highly prevalent, with 201 (40.6%) and 131 (26.5%) of youth reporting history of each, respectively. Increasing CTQ score was related to risk for suicide attempt despite adjustment for confounders (adjusted odds ratio [AOR], 1.45 per standard deviation increase in score; 95% confidence interval [CI], 1.08-1.91).

LIMITATIONS

Use of snowball sampling may not have produced a truly random sample, and reliance on self-report may have resulted in underreporting of risk behaviors among participants. Moreover, use of cross-sectional data limits the degree to which temporality can be concluded from the results of this study alone.

CONCLUSIONS

There exists a strong and graded association between childhood trauma and subsequent attempted suicide among street youth, an otherwise 'hidden' population. There is a need for effective interventions that not only prevent maltreatment of children but also aid youth at increased risk for suicide given prior history of trauma.

The street cost of drugs and drug use patterns: relationships with sex work income in an urban Canadian setting

BACKGROUND

This study investigated the relationship between drug use and sex work patterns and sex work income earned among street-based female sex workers (FSWs) in Vancouver, Canada.

METHODS

We used data from a sample of 129 FSWs who used drugs in a prospective cohort (2007-2008), for a total of 210 observations. Bivariate and multivariable linear regression using generalized estimating equations was used to model the relationship between explanatory factors and sex work income. Sex work income was log-transformed to account for skewed data.

RESULTS

The median age of the sample at first visit was 37 years (interquartile range[IQR]: 30-43), with 46.5% identifying as Caucasian, 48.1% as Aboriginal and 5.4% as another visible minority. The median weekly sex work income and amount spent on drugs was $300 (IQR=$100-$560) and $400 (IQR=$150-$780), respectively. In multivariable analysis, for a 10% increase in money spent on drugs, sex work income increased by 1.9% (coeff: 0.20, 95% CIs: 0.04-0.36). FSWs who injected heroin, FSWs with higher numbers of clients and youth compared to older women (<25 versus 25+ years) also had significantly higher sex work income.

CONCLUSIONS

This study highlights the important role that drug use plays in contributing to increased dependency on sex work for income among street-based FSWs in an urban Canadian setting, including a positive dose-response relationship between money spent on drugs and sex work income. These findings indicate a crucial need to scale up access and availability of evidence-based harm reduction and treatment approaches, including policy reforms, improved social support and economic choice for vulnerable women.

A comparison of drug use and risk behavior profiles among younger and older street youth

Among 559 street youth recruited between 2005 and 2007 in Vancouver, Canada, young drug users (<21 years of age) were compared with older drug users (≥21 years) with regard to recent drug use and sexual practices using multiple logistic regression. Older youth were more likely to be male and of Aboriginal ancestry, to have more significant depressive symptoms, to have recently engaged in crack smoking, and to have had a recent history of injection drug use. Young drug users, by contrast, were more likely to have engaged in recent binge alcohol use. Efforts to reduce drug use-related harm among street youth may be improved by considering the highly prevalent use of "harder" drugs and risk for depression among older youth.

Crystal methamphetamine use among female street-based sex workers: Moving beyond individual-focused interventions

Given growing concern of the sexual risks associated with crystal methamphetamine use and the dearth of research characterizing the use of methamphetamine among street-based sex workers (FSWs), this study aimed to characterize the prevalence and individual, social, and structural contexts of crystal methamphetamine use among FSWs in a Canadian setting. Drawing on data from a prospective cohort, we constructed multivariate logistic models to examine independent correlates of crystal methamphetamine among FSWs over a two-year follow-up period using generalized estimating equations. Of a total of 255 street-based FSWs, 78 (32%) reported lifetime crystal methamphetamine use and 24% used crystal methamphetamine during the two-year follow-up period, with no significant associations between methamphetamine use and sexual risk patterns. In a final multivariate GEE model, FSWs who used crystal methamphetamine had a higher proportional odds of dual heroin injection (adjOR=2.98, 95%CI: 1.35-5.22), having a primary male sex partner who procures drugs for them (adjOR=1.79, 95%CI: 1.02-3.14), and working (adjOR=1.62, 95%CI: 1.04-2.65) and living (adjOR=1.41, 95%CI: 1.07-1.99) in marginalized public spaces. The findings highlight the crucial need to move beyond the individual to gender-focused safer environment interventions that mediate the physical and social risk environment of crystal methamphetamine use among FSWs.

Prevalence of bone mineral density abnormalities and related risk factors in an ambulatory HIV clinic population

Bone mineral density (BMD) abnormalities are observed frequently among human immunodeficiency virus (HIV)-infected patients. Risk factors for reduced BMD in the setting of HIV have been previously studied, but detailed antiretroviral treatment history is often not available. A cross-sectional observational study was conducted between 2005 and 2007 among unselected HIV-infected adults attending an ambulatory urban HIV clinic. Dual-energy X-ray absorptiometry (DXA) scans of lumbar spine and femoral neck, full laboratory profile, detailed questionnaire, and antiretroviral history were obtained. Univariate and multivariate logistic regression analyses were performed to investigate factors associated with BMD below the expected range for age. Two hundred ninety patients completed the study: 80% Caucasians, 89% males, with median age of 49 yr. Low BMD as assessed by Z-score was present in 19.7% of the patients. By multivariate analysis, only lower body mass index (BMI) was an independent risk factor for low BMD. Cumulative exposure to protease inhibitors, non-nucleosides, and individual nucleoside and nucleotide analogs were not independently associated with low BMD. In conclusion, a 19.7% prevalence of abnormal BMD by DXA scan was identified in an unselected group of HIV-infected adults. Lower BMI was independently associated with low BMD. No correlation was found between abnormal BMD and cumulative exposure to any antiretroviral agents.

Non-Injection Drug Use Patterns and History of Injection among Street Youth

AIMS

Efforts to prevent youth from initiating injection drug use require an understanding of the drug use patterns that predispose to injecting. Here we identify such patterns and describe the circumstances of first injection among street youth.

METHODS

From October 2005 to November 2007, data were collected for the At Risk Youth Study, a prospective cohort of 560 street-recruited youth aged 14-26 in Vancouver, Canada. Non-injection drug use behaviors were compared between those with and without a history of injection through multiple logistic regression. The circumstances of first injection were also examined in gender-stratified analyses.

RESULTS

Youth who had previously injected were more likely to have engaged in non-injection use of heroin or of crystal methamphetamine. Daily users of marijuana were less likely to have injected. Among prior injectors, the median age of first injection was lower among females. Females were also more likely to have had a sexual partner present at first injection and to have become a regular injector within one week of initiation.

CONCLUSION

Preventing transition to injection among street youth may require special attention to predisposing drug use patterns and should acknowledge gender differences in the circumstances of first injection.

Prevalence and structural correlates of gender based violence among a prospective cohort of female sex workers

OBJECTIVE

To examine the prevalence and structural correlates of gender based violence against female sex workers in an environment of criminalised prostitution.

DESIGN

Prospective observational study.

SETTING

Vancouver, Canada during 2006-8.

PARTICIPANTS

Female sex workers 14 years of age or older (inclusive of transgender women) who used illicit drugs (excluding marijuana) and engaged in street level sex work.

MAIN OUTCOME MEASURE

Self reported gender based violence.

RESULTS

Of 267 female sex workers invited to participate, 251 women returned to the study office and consented to participate (response rate of 94%). Analyses were based on 237 female sex workers who completed a baseline visit and at least one follow-up visit. Of these 237 female sex workers, 57% experienced gender based violence over an 18 month follow-up period. In multivariate models adjusted for individual and interpersonal risk practices, the following structural factors were independently correlated with violence against female sex workers: homelessness (adjusted odds ratio for physical violence (aOR(physicalviolence)) 2.14, 95% confidence interval 1.34 to 3.43; adjusted odds ratio for rape (aOR(rape)) 1.73, 1.09 to 3.12); inability to access drug treatment (adjusted odds ratio for client violence (aOR(clientviolence)) 2.13, 1.26 to 3.62; aOR(physicalviolence) 1.96, 1.03 to 3.43); servicing clients in cars or public spaces (aOR(clientviolence) 1.50, 1.08 to 2.57); prior assault by police (aOR(clientviolence) 3.45, 1.98 to 6.02; aOR(rape) 2.61, 1.32 to 5.16); confiscation of drug use paraphernalia by police without arrest (aOR(physicalviolence) 1.50, 1.02 to 2.41); and moving working areas away from main streets owing to policing (aOR(clientviolence) 2.13, 1.26 to 3.62).

CONCLUSIONS

Our results demonstrate an alarming prevalence of gender based violence against female sex workers. The structural factors of criminalisation, homelessness, and poor availability of drug treatment independently correlated with gender based violence against street based female sex workers. Socio-legal policy reforms, improved access to housing and drug treatment, and scale up of violence prevention efforts, including police-sex worker partnerships, will be crucial to stemming violence against female sex workers.

Determinants of cutaneous injection-related infection care at a supervised injecting facility

PURPOSE

To evaluate the factors associated with receiving cutaneous injection-related infection (CIRI) care among a representative cohort of supervised injecting facility (SIF) users.

METHODS

Data were collected biannually as part of a prospective cohort, the Scientific Evaluation of Supervised Injection study. Kaplan-Meier methods and Cox proportional hazards regression with recurrent events were used to examine incidence and factors associated with CIRI care, respectively.

RESULTS

One thousand eighty individuals were recruited between December 1, 2003 and January 31, 2008. The incidence density of participants receiving CIRI care was 22.0 per 100 person-years (95% confidence interval [CI]: 19.6-24.6). In the adjusted Cox proportional hazard model, female sex (adjusted hazard ratio [AHR]=1.87 [95% CI: 1.32-2.64]), unstable housing (AHR=1.39 [95% CI: 1.02-1.88]), and daily heroin injection (AHR=1.52 [95% CI: 1.13-2.04]) were independently associated with receiving CIRI care at the SIF.

CONCLUSIONS

These results describe who is more likely to receive CIRI care, which is of use to those engaged with policy and practice of treatment regimens involving this population.

Access to drug and alcohol treatment among a cohort of street-involved youth

BACKGROUND

A number of options for treatment are available to young drug users, but little is known about the youth who actually attempt to access such services. Here we identify characteristics of a cohort of street-involved youth and highlight commonly encountered barriers.

METHODS

From September 2005 to July 2007, data were collected from the At-Risk Youth Study (ARYS), a prospective cohort of 529 drug users aged 14-26 living in Vancouver, Canada. Participants who attempted to access any addiction services in the 6 months prior to enrollment were compared in univariate analyses and multiple logistic regression modeling of socio-demographic and drug-related factors.

RESULTS

Factors positively associated with attempting to access services included Aboriginal ethnicity (adjusted odds ratio [AOR]=1.66 [1.05-2.62]), high school education (AOR=1.66 [1.09-2.55]), mental illness (AOR=2.25 [1.50-3.38]), non-injection crack use (AOR=2.93 [1.76-4.89]), and spending >$50 on drugs per day (AOR=2.13 [1.41-3.22]). Among those who experienced difficulty-accessing services, the most commonly identified barrier was excessively long waiting lists. In a subgroup analysis comparing those who tried to access services but were unsuccessful to those who were successful, risk factors positively associated with failure included drug bingeing (odds ratio [OR]=2.86 [1.22-6.76]) and homelessness (OR=3.86 [1.11-13.4]).

CONCLUSIONS

In light of accumulating evidence that drug use among street youth is associated with risky health-related behaviors, improving access to treatment and other addiction services should remain an important public health priority.

Liver ultrastructural morphology and mitochondrial DNA levels in HIV/hepatitis C virus coinfection: no evidence of mitochondrial damage with highly active antiretroviral therapy

Liver mitochondrial toxicity is a concern, particularly in HIV/hepatitis C virus (HCV) coinfection. Liver biopsies from HIV/HCV co-infected patients, 14 ON-highly active antiretroviral therapy (HAART) and nine OFF-HAART, were assessed by electron microscopy quantitative morphometric analyses. Hepatocytes tended to be larger ON-HAART than OFF-HAART (P = 0.05), but mitochondrial volume, cristae density, lipid volume, mitochondrial DNA and RNA levels were similar. We found no evidence of increased mitochondrial toxicity in individuals currently on HAART, suggesting that concomitant HAART should not delay HCV therapy.

Dermatologic Manifestations of Underlying Infectious Disease among Illicit Injection-Drug Users

Background:

Drug use patterns and serious bloodborne infections commonly have dermatologic manifestations among illicit injection-drug users (IDUs).

Objective:

To assess how self-reported skin conditions of IDUs may correlate with underlying infectious diseases after adjustment for drug use patterns.

Methods:

Prospective analysis of factors associated with self-reports of skin rashes, cellulitis, oral lesions, and lymphadenopathy obtained from 1,065 IDUs enrolled in a large cohort study. Variables potentially associated with each outcome were evaluated using multivariate generalized estimating equations.

Results:

In multivariate analyses, drug use patterns were associated with cellulitis, whereas human immunodeficiency virus (HIV) infection and hepatitis C (HCV) were not. HCV infection was independently associated with skin rashes (odds ratio [OR] 1.85; 95% Cl 1.17–2.94). HIV infection was independently associated with lymphadenopathy (OR 2.00; 95% CI 1.52–2.63), skin rash (OR 2.12; 95% CI 1.57–2.86), and oral lesions (OR 14.95; 95% CI 9.41–23.76).

Conclusions:

Self-reports of IDUs, which could easily be obtained as part of a functional inquiry in a clinical setting, correlate with specific drug use patterns and underlying bloodborne infections.

Rate of methadone use among Aboriginal opioid injection drug users

BACKGROUND

Previous studies have shown elevated rates of health-related harms among Aboriginal people who use injection drugs such as heroin. Methadone maintenance therapy is one of the most effective interventions to address the harms of heroin injection. We assessed the rate of methadone use in a cohort of opioid injection drug users in Vancouver and investigated whether methadone use was associated with Aboriginal ethnic background.

METHODS

Using data collected as part of the Vancouver Injection Drug Users Study (May 1996-November 2005), we evaluated whether Aboriginal ethnic background was associated with methadone use using generalized estimating equations and Cox regression analysis. We compared methadone use among Aboriginal and non-Aboriginal injection drug users at the time of enrollment and during the follow-up period, and we evaluated the time to first methadone use among people not using methadone at enrollment.

RESULTS

During the study period, 1603 injection drug users (435 Aboriginal, 1168 non-Aboriginal) were recruited. At enrollment, 54 (12.4%) Aboriginal participants used methadone compared with 247 (21.2%) non-Aboriginal participants (odds ratio [OR] 0.53, 95% confidence interval [CI] 0.38-0.73, p < 0.001). Among the 1351 (84.3%) participants who used heroin, Aboriginal people were less likely to use methadone throughout the follow-up period (adjusted OR 0.60, 95% CI 0.45-0.81, p < 0.001). Among people using heroin but who were not taking methadone at enrollment, Aboriginal ethnic background was associated with increased time to first methadone use (adjusted relative hazard 0.60, 95% CI 0.49-0.74, p < 0.001).

INTERPRETATION

Methadone use was lower among Aboriginal than among non-Aboriginal injection drug users. Culturally appropriate interventions with full participation of the affected community are required to address this disparity.

The safety of tenofovir disoproxil fumarate for the treatment of HIV infection in adults: the first 4 years

OBJECTIVE

To characterize the safety profile of tenofovir disoproxil fumarate (DF) for the treatment of HIV infection in adults over the first 4 years of use.

METHODS

A tenofovir DF expanded access program (EAP) was initiated in 2001; safety data were examined from this program and from the manufacturer's database, which contained reports of all postmarketing adverse drug reactions received up to 30 April 2005. Specific analyses were performed to characterize the renal safety of tenofovir DF.

RESULTS

The EAP enrolled 10 343 patients; serious adverse events (SAEs) were reported in 631 (6%). A renal SAE of any type was observed in 0.5% of patients, and graded elevations in serum creatinine occurred in 2.2% of the patients evaluated. In a multivariate analysis, baseline risk factors for the development of increased serum creatinine on-study were elevated serum creatinine, concomitant nephrotoxic medications, low body weight, advanced age, and lower CD4 cell count. For postmarketing safety data (455 392 person-years of exposure to tenofovir DF) the most commonly reported serious adverse drug reactions were renal events, with a distribution by type similar to that observed in the EAP. Bone abnormalities were infrequently reported in either the EAP or the postmarketing safety databases. No new unexpected toxicities were identified in postmarketing safety surveillance.

CONCLUSIONS

The data demonstrate a favorable safety profile for tenofovir DF in the treatment of adults with HIV infection. Risk factors for development of nephrotoxicity can be identified and may be useful in managing those patients at greatest risk.

Increasing use and associated harms of crystal methamphetamine injection in a Canadian setting

BACKGROUND

There is a growing concern surrounding crystal methamphetamine use in Canada despite surprisingly little empirical data to support such claims. We evaluated the trends in crystal methamphetamine injection and factors associated with injection of the drug among a cohort of injection drug users (IDU) in Vancouver.

METHODS

We conducted a prospective analysis of factors associated with crystal methamphetamine injection among participants enrolled in the Vancouver Injection Drug Users Study (VIDUS). Since serial measures for each individual were available, variables potentially associated with crystal methamphetamine injection were evaluated using generalized estimating equations (GEE) with logit link for binary outcomes.

RESULTS

Overall, 1587 IDU were enrolled into the VIDUS cohort between May 1996 and December 2004. The proportion of IDU who reported injecting crystal methamphetamine during the last 6 months increased during the study period (Cochran-Armitage trend test, p<0.001). In multivariate GEE analyses, crystal methamphetamine injection was independently associated with younger age (adjusted odds ratio [AOR]: 4.77, 95% confidence interval [CI]=3.40-6.70), Caucasian ethnicity (AOR=2.21, 95% CI=1.57-3.12), syringe borrowing (AOR=1.62, 95% CI=1.22-2.13), and syringe lending (AOR=1.40, 95% CI=1.02-1.86).

INTERPRETATION

There was a significant trend towards increasing crystal methamphetamine injection in this setting and elevated HIV risk behavior and younger age were independently associated with crystal methamphetamine injection. Given that banning precursor chemicals has had a limited effect on reducing methamphetamine supply in other jurisdictions, pragmatic and effective interventions are needed to address the growing use of this drug.

Summary of findings from the evaluation of a pilot medically supervised safer injecting facility

In many cities, infectious disease and overdose epidemics are occurring among illicit injection drug users (IDUs). To reduce these concerns, Vancouver opened a supervised safer injecting facility in September 2003. Within the facility, people inject pre-obtained illicit drugs under the supervision of medical staff. The program was granted a legal exemption by the Canadian government on the condition that a 3-year scientific evaluation of its impacts be conducted. In this review, we summarize the findings from evaluations in those 3 years, including characteristics of IDUs at the facility, public injection drug use and publicly discarded syringes, HIV risk behaviour, use of addiction treatment services and other community resources, and drug-related crime rates. Vancouver's safer injecting facility has been associated with an array of community and public health benefits without evidence of adverse impacts. These findings should be useful to other cities considering supervised injecting facilities and to governments considering regulating their use.

The direct costs of HIV/AIDS care

We reviewed published studies reporting the direct medical costs of treating HIV-infected people in countries using highly active antiretroviral therapy (HAART). Of 543 potentially relevant studies, only nine provided adequate data to make a meaningful statement about costs. Within studies, people with more advanced disease incurred higher total costs. Valid comparisons of total direct medical costs between studies were not possible because of differences in the specific components included, the heterogeneous nature of study populations in terms of disease stage, the sources and methods used to estimate unit costs, and the level of aggregation at which results were reported. The advent of HAART has major implications for the cost of treating HIV-infected individuals. Although this information is important for planning purposes, only a small number of published studies provide useful estimates of the direct cost. A useful method of estimating resource use and costs is computer simulation.

The impact of sex partners' HIV status on HIV seroconversion in a prospective cohort of injection drug users

OBJECTIVE AND DESIGN

The identification of individuals at highest risk of HIV infection is critical for targeting prevention strategies. We evaluated the HIV status of the sex partners of injection drug users (IDUs) and rates of subsequent HIV seroconversion among a prospective cohort study of IDUs.

METHODS

We performed an analysis of the time to HIV infection among baseline HIV-negative IDUs enrolled in the Vancouver Injection Drug Users Study. IDUs were stratified based on whether or not they reported having an HIV-positive sex partner. Kaplan-Meier methods were used to estimate cumulative HIV incidence rates, and Cox regression was used to determine adjusted relative hazards (RHs) for HIV seroconversion.

RESULTS

Of 1013 initially HIV-negative IDUs, 4.8% had an HIV-positive partner at baseline. After 18 months, the cumulative HIV incidence rate was significantly elevated among those who reported having an HIV-positive sex partner (23.4% vs. 8.1%; log-rank P < 0.001). In a Cox regression model adjusting for all variables that were associated with the time to HIV infection in univariate analyses, including drug use characteristics, having an HIV-positive sex partner (RH = 2.42 [95% confidence interval: 1.30 to 4.60]; P = 0.005) remained independently associated with time to HIV seroconversion.

CONCLUSIONS

Having an HIV-positive sex partner was strongly and independently associated with seroconversion after adjustment for risk factors related to drug use. Our findings may aid public health workers in their efforts to identify IDUs who should be targeted with education and prevention efforts and indicate the need for ongoing development of prevention interventions for IDU sex partners who are HIV discordant.

Exploring Mitochondrial Nephrotoxicity as a Potential Mechanism of Kidney Dysfunction among HIV-Infected Patients on Highly Active Antiretroviral Therapy

Background

Tenofovir (TDF) exposure has been associated with renal dysfunction. Mitochondrial nephrotoxicity was investigated as an underlying mechanism. Given the interaction between TDF and didanosine (ddI), their concurrent use was also investigated.

Design

Relative kidney biopsy mitochondrial DNA (mtDNA) to nuclear DNA ratios were measured retrospectively. HIV+ individuals on TDF within 6 months preceeding the biopsy (HIV+/TDF+, n=21) were compared to HIV+ individuals who never received TDF (HIV+/TDF-, n=10) and to HIV uninfected controls (HIV–, n=22). Twelve of the HIV+/TDF+ individuals received concurrent ddI, 10 of those once at unadjusted ddI dosage. Tubular mitochondria morphology was also examined by electron microscopy. Statistical analyses were done on log-transformed mtDNA/nDNA, using non-parametric tests.

Results

Kidney mtDNA levels were different among the three groups ( P=0.046). mtDNA ratios were lower in HIV+/TDF+ subjects (7.5 [2.0–12.1]) than in HIV- ones (14.3 [6.0–16.5], P=0.014), but not lower than HIV+/TDF-controls (6.4 [2.8–11.9], P=0.82). Among HIV+ subjects, there was a difference between TDF-, TDF+/ddI- and TDF+/ddI+ ( P=0.005), with concurrent TDF/ddI use associated with lower mtDNA (2.1 [1.9–5.5], n=12) than TDF+/ddI- (13.8 [7.5–16.4], n=9, P=0.003). No TDF–/ddI+ biopsies were available. In regression analyses, only HIV infection ( P=0.03), and TDF/ddI use ( P=0.003) were associated with lower mtDNA. At the ultrastructural level, abnormal tubular mitochondria was more prevalent in HIV+/TDF+ biopsies than HIV+/TDF- and HIV- ones together ( P<0.001) but not more so in TDF+/ddI+ biopsies than TDF+/ddI- ones ( P=0.67).

Conclusions

Renal dysfunction in this population may be mediated through mitochondrial nephrotoxicity that involves more than one drug and/or pathogenesis. Kidney mtDNA depletion was associated with HIV infection and concurrent TDF/ddI therapy but not TDF use alone, while kidney ultrastructural mitochondrial abnormalities were seen with TDF use. The interaction between TDF and ddI may be relevant in the kidney where both drugs are cleared. The clinical relevance of our findings needs to be evaluated given the current recommendation for reduced doses of ddI when used in conjunction with TDF.

Exploring mitochondrial nephrotoxicity as a potential mechanism of kidney dysfunction among HIV-infected patients on highly active antiretroviral therapy

BACKGROUND

Tenofovir (TDF) exposure has been associated with renal dysfunction. Mitochondrial nephrotoxicity was investigated as an underlying mechanism. Given the interaction between TDF and didanosine (ddl), their concurrent use was also investigated.

DESIGN

Relative kidney biopsy mitochondrial DNA (mtDNA) to nuclear DNA ratios were measured retrospectively. HIV+ individuals on TDF within 6 months preceeding the biopsy (HIV+/TDF+, n=21) were compared to HIV+ individuals who never received TDF (HIV+/TDF-, n=10) and to HIV uninfected controls (HIV-,n=22). Twelve of the HIV+/TDF+ individuals received concurrent ddl, 10 of those once at unadjusted ddl dosage. Tubular mitochondria morphology was also examined by electron microscopy. Statistical analyses were done on log-transformed mtDNA/nDNA, using non-parametric tests.

RESULTS

Kidney mtDNA levels were different among the three groups (P=0.046). mtDNA ratios were lower in HIV+/TDF+ subjects (7.5 [2.0-12.1]) than in HIV- ones (14.3 [6.0-16.5], P=0.014), but not lower than HIV+/TDF- controls (6.4 [2.8-11.9], P=0.82). Among HIV+ subjects, there was a difference between TDF-, TDF+/ddl- and TDF+/ddl+ (P=0.005), with concurrent TDF/ddl use associated with lower mtDNA (2.1 [1.9-5.5], n=12) than TDF+/ddl- (13.8 [7.5-16.4], n=9, P=0.003). No TDF-/ddl+ biopsies were available. In regression analyses, only HIV infection (P=0.03), and TDF/ddl use (P=0.003) were associated with lower mtDNA. At the ultrastructural level, abnormal tubular mitochondria was more prevalent in HIV+/TDF+ biopsies than HIV+/TDF- and HIV- ones together (P<0.001) but not more so in TDF+/ddl+ biopsies than TDF+/ddl- ones (P=0.67).

CONCLUSIONS

Renal dysfunction in this population may be mediated through mitochondrial nephrotoxicity that involves more than one drug and/or pathogenesis. Kidney mtDNA depletion was associated with HIV infection and concurrent TDF/ddl therapy but not TDF use alone, while kidney ultrastructural mitochondrial abnormalities were seen with TDF use. The interaction between TDF and ddl may be relevant in the kidney where both drugs are cleared. The clinical relevance of our findings needs to be evaluated given the current recommendation for reduced doses of ddl when used in conjunction with TDF.