M.-J. Milloy

Reduction in overdose mortality after the opening of North America's first medically supervised safer injecting facility: a retrospective population-based study

BACKGROUND Overdose from illicit drugs is a leading cause of premature mortality in North America. Internationally, more than 65 supervised injecting facilities (SIFs), where drug users can inject pre-obtained illicit drugs, have been opened as part of various strategies to reduce the harms associated with drug use. We sought to determine whether the opening of an SIF in Vancouver, BC, Canada, was associated with a reduction in overdose mortality. METHODS We examined population-based overdose mortality rates for the period before (Jan 1, 2001, to Sept 20, 2003) and after (Sept 21, 2003, to Dec 31, 2005) the opening of the Vancouver SIF. The location of death was determined from provincial coroner records. We compared overdose fatality rates within an a priori specified 500 m radius of the SIF and for the rest of the city. FINDINGS Of 290 decedents, 229 (79·0%) were male, and the median age at death was 40 years (IQR 32-48 years). A third (89, 30·7%) of deaths occurred in city blocks within 500 m of the SIF. The fatal overdose rate in this area decreased by 35·0% after the opening of the SIF, from 253·8 to 165·1 deaths per 100,000 person-years (p=0·048). By contrast, during the same period, the fatal overdose rate in the rest of the city decreased by only 9·3%, from 7·6 to 6·9 deaths per 100,000 person-years (p=0·490). There was a significant interaction of rate differences across strata (p=0·049). INTERPRETATION SIFs should be considered where injection drug use is prevalent, particularly in areas with high densities of overdose. FUNDING Vancouver Coastal Health, Canadian Institutes of Health Research, and the Michael Smith Foundation for Health Research.

Homelessness as a Structural Barrier to Effective Antiretroviral Therapy Among HIV-Seropositive Illicit Drug Users in a Canadian Setting

Despite the advent of effective antiretroviral therapy (ART), HIV-seropositive injection drug users (IDU) continue to suffer from elevated levels of morbidity and mortality. Evidence is needed to identify social- and structural-level barriers to effective ART. We investigated the impact of homelessness on plasma HIV RNA response among illicit drug users initiating ART in a setting with free and universal access to HIV care. We accessed data from a long-running prospective cohort of community-recruited IDU linked to comprehensive HIV clinical monitoring and ART dispensation records. Using Cox proportional hazards with recurrent events modeling, we estimated the independent effect of homelessness on time to plasma HIV viral load suppression. Between May 1996 and September 2009, 247 antiretroviral naïve individuals initiated ART and contributed 1755 person-years of follow-up. Among these individuals, the incidence density of plasma HIV RNA suppression less than 500 copies/mm(3) was 56.7 (95% confidence interval [CI]: 46.9-66.0) per 100 person-years. In unadjusted analyses, homelessness was strongly associated with lower rates suppression (hazard ratio = 0.56, 95% CI: 0.40-0.78, p = 0.001), however, after adjustment for adherence this association was no longer significant (adjusted hazard ratio = 0.79, 95% CI: 0.56-1.11, p = 0.177). Homelessness poses a significant structural barrier to effective HIV treatment. However, since this relationship appears to be mediated by lower levels of ART adherence, interventions to improve adherence among members of this vulnerable population are needed.

Incidence and risk factors for non-fatal overdose among a cohort of recently incarcerated illicit drug users

BACKGROUND Release from prison is associated with a markedly increased risk of both fatal and non-fatal drug overdose, yet the risk factors for overdose in recently released prisoners are poorly understood. The aim of this study was to identify risk and protective factors for non-fatal overdose (NFOD) among a cohort of illicit drug users in Vancouver, Canada, according to recent incarceration. METHODS Prospective cohort of 2515 community-recruited illicit drug users in Vancouver, Canada, followed from 1996 to 2010. We examined factors associated with NFOD in the past six months separately among those who did and did not also report incarceration in the last six months. RESULTS One third of participants (n=829, 33.0%) reported at least one recent NFOD. Among those recently incarcerated, risk factors independently and positively associated with NFOD included daily use of heroin, benzodiazepines, cocaine or methamphetamine, binge drug use, public injecting and previous NFOD. Older age, methadone maintenance treatment and HIV seropositivity were protective against NFOD. A similar set of risk factors was identified among those who had not been incarcerated recently. CONCLUSIONS Among this cohort, and irrespective of recent incarceration, NFOD was associated with a range of modifiable risk factors including more frequent and riskier patterns of drug use. Not all ex-prisoners are at equal risk of overdose and there remains an urgent need to develop and implement evidence-based preventive interventions, targeting those with modifiable risk factors in this high risk group.

Housing Status and the Health of People Living with HIV/AIDS

Individuals who are homeless or living in marginal conditions have an elevated burden of infection with HIV. Existing research suggests the HIV/AIDS pandemic in resource-rich settings is increasingly concentrated among members of vulnerable and marginalized populations, including homeless/marginally-housed individuals, who have yet to benefit fully from recent advances in highly-active antiretroviral therapy (HAART). We reviewed the scientific evidence investigating the relationships between inferior housing and the health status, HAART access and adherence and HIV treatment outcomes of people living with HIV/AIDS (PLWHA.) Studies indicate being homeless/marginally-housed is common among PLWHA and associated with poorer levels of HAART access and sub-optimal treatment outcomes. Among homeless/marginally-housed PLWHA, determinants of poorer HAART access/adherence or treatment outcomes include depression, illicit drug use, and medication insurance status. Future research should consider possible social- and structural-level determinants of HAART access and HV treatment outcomes that have been shown to increase vulnerability to HIV infection among homeless/marginally-housed individuals. As evidence indicates homeless/marginally-housed PLWHA with adequate levels of adherence can benefit from HAART at similar rates to housed PLWHA, and given the individual and community benefits of expanding HAART use, interventions to identify HIV-seropositive homeless/marginally-housed individuals, and engage them in HIV care including comprehensive support for HAART adherence are urgently needed.

Severe food insecurity is associated with elevated unprotected sex among HIV-seropositive injection drug users independent of HAART use.

Objective:Despite emerging evidence of a significant adverse relationship between food insecurity and sexual risk-taking, data have been primarily derived from resource-constrained settings and HIV-negative populations. To our knowledge, this study is the first to longitudinally evaluate the relationship between food insecurity and unprotected sex among HIV-seropositive people who inject drugs [injection drug users (IDUs)] both on and not on HAART. Design:Longitudinal analyses were restricted to HIV-positive IDUs who completed baseline and at least one follow-up visit in a prospective cohort (AIDS Care Cohort to evaluate Exposure to Survival Services, 2005–2009). Methods:We constructed a multivariate logistic model using generalized estimating equations (GEEs) to assess an independent relationship between severe food insecurity (e.g., hunger due to lack of access or means to acquire food) and unprotected vaginal/anal sex. Results:Among 470 HIV-positive IDUs, the median age was 42 years (interquartile range 36–47) with 61% men and 39% women. The prevalence of severe food insecurity was 71%, with no differences by HAART use. Severe food insecure IDUs were marginally less likely to have a suppressed HIV-1 RNA viral load (31 vs. 39%, P = 0.099). In multivariate GEE analyses, severe food insecurity [adjusted odds ratio = 2.68, 95% confidence interval 1.49–4.82] remained independently correlated with unprotected sex among HIV-positive IDUs, controlling for age, sex/gender, married/cohabitating partner, binge drug use, homelessness, and HAART use. Conclusion:These findings highlight a crucial need for structural HIV interventions that incorporate targeted food assistance strategies for IDUs. Given recent evidence of poor virological response among food insecure individuals on HAART, innovative HIV care models should integrate targeted food security programs and early access to HAART.

HIV treatment as prevention among injection drug users.

PURPOSE OF REVIEW The use of highly active antiretroviral therapy (HAART) as a strategy to prevent the transmission of HIV infection is of substantial international interest. Injection drug users (IDUs) are an important population with respect to HIV treatment as prevention because they are often less likely to access HAART in comparison with other risk groups. RECENT FINDINGS A recent multicentre randomized clinical trial demonstrated a 96% reduction in HIV transmission among heterosexual serodiscordant couples prescribed early HAART. Consistent with these results, independent observational studies from Baltimore and Vancouver have demonstrated that population level rates of HAART use among IDUs are associated with reduced rates of HIV incidence. In addition, impact assessments of HAART delivery to IDUs have generally demonstrated no negative effects of HAART use on rates of unsafe sex or syringe sharing. SUMMARY HAART prevents HIV transmission because it dramatically decreases HIV-1 RNA levels in biological fluids. This is relevant to vertical and sexual HIV transmission and also to blood-borne HIV transmission, as it is often the case among IDUs. Efforts to expand HAART to IDUs should be redoubled in an effort to realize both the individual and public health benefits of HAART.

High-risk drug-use practices among a large sample of Australian prisoners

BACKGROUND Drug injection in prison is associated with a high risk of transmission of blood-borne pathogens including hepatitis C (HCV). The aim of this study was to estimate the prevalence and identify independent correlates of recent in-prison injecting drug use (P-IDU) among a large sample of adult prisoners in Queensland, Australia. METHODS Confidential, structured interviews with 1,322 adult prisoners in Queensland, Australia. Prevalence estimates were corrected for sampling bias using inverse probability weighting. Independent correlates of recent P-IDU were identified using multivariable Poisson regression with backwards elimination. RESULTS We estimated that among all adult prisoners in Queensland, Australia, the prevalence of lifetime IDU was 55.1%, of lifetime P-IDU 23.0%, and of recent (during current sentence) P-IDU 13.2%. Significant, independent correlates of recent P-IDU included male gender (ARR=3.07, 95% CI 1.83-5.12), being unemployed prior to incarceration (ARR=1.34, 95% CI 1.01-1.76), use of three or more drug types prior to incarceration (ARR=1.80, 95% CI 1.40-2.31), a history of needle/syringe sharing (ARR=5.00, 95% CI 3.06-8.16), receiving a tattoo during the current prison sentence (ARR=2.19, 95% CI 1.67-2.86) and HCV exposure (ARR=1.47, 95% CI 1.08-2.02). Older age was protective (ARR=0.90 per 5 years older, 95% CI 0.83-0.99). CONCLUSION Drug injection in prison is common and, given the associations between in-prison drug injection and syringe sharing, unsafe tattooing and HCV exposure, poses a risk to both prisoner health and public health. There remains an urgent need to implement evidence-based infection control measures, including needle and syringe programs, within prison settings.

Incarceration and drug use patterns among a cohort of injection drug users.

AIMS Drug law enforcement remains the dominant response to drug-related harm. However, the impact of incarceration on deterring drug use remains under-evaluated. We sought to explore the relationship between incarceration and patterns of drug use among people who inject drugs (IDU). DESIGN Using generalized estimating equations (GEE), we examined the prevalence and correlates of injection cessation among participants in the Vancouver Injection Drug User Study followed over 9 years. In subanalyses, we used McNemars tests and linear growth curve analyses to assess changes in drug use patterns before and after a period of incarceration among participants reporting incarceration and those not incarcerated. FINDINGS Among 1603 IDU, 842 (53%) reported injection cessation for at least 6 months at some point during follow-up. In multivariate GEE analyses, recent incarceration was associated negatively with injection cessation [adjusted odds ratio (AOR) = 0.43, 95% confidence interval (CI) 0.37-0.50], whereas the use of methadone was associated positively with cessation (AOR = 1.38, 95% CI 1.22-1.56). In subanalyses assessing longitudinal patterns of drug use among incarcerated individuals and those not incarcerated over the study period, linear growth curve analyses indicated that there were no statistically significant differences in patterns of drug use between the two groups (all P > 0.05). CONCLUSIONS These observational data suggest that incarceration does not reduce drug use among IDU. Incarceration may inhibit access to mechanisms that promote injection cessation among IDU. In contrast, results indicate that methadone use is associated positively with injection cessation, independent of previous frequency of drug use.

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.

High prevalence of childhood emotional, physical and sexual trauma among a Canadian cohort of HIV-seropositive illicit drug users

Abstract Background . The psychosocial impacts of various types of childhood maltreatment on vulnerable illicit drug-using populations remain unclear. We examined the prevalence and correlates of antecedent emotional, physical and sexual abuse among a community-recruited cohort of adult HIV-seropositive illicit drug users. Methods . We estimated the prevalence of childhood abuse at baseline using data from the Childhood Trauma Questionnaire, a 28-item validated instrument used to retrospectively assess childhood maltreatment. Logistic regression was used to estimate relationships between sub-types of childhood maltreatment with various social-demographic, drug-using and clinical characteristics. Results . Overall, 233 HIV-positive injection drug users (IDU) were included in the analysis, including 83 (35.6%) women. Of these, moderate or severe emotional childhood abuse was reported by 51.9% of participants, emotional neglect by 36.9%, physical abuse by 51.1%, physical neglect by 46.8% and sexual abuse by 41.6%. In multivariate analyses, emotional, physical and sexual abuses were independently associated with greater odds of recent incarceration. Emotional abuse and neglect were independently associated with a score of ≥16 on the Centre for Epidemiologic Studies Depression Scale. There was no association between any form of childhood maltreatment and clinical HIV variables, including viral load, CD4+ count and history of antiretroviral therapy use. Conclusion . These findings underscore the negative impact of childhood maltreatment on social functioning and mental health in later life. Given the substantial prevalence of childhood maltreatment among this population, there is a need for evidence-based resources to address the deleterious effect it has on the health and social functioning of HIV-positive IDU.