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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-positive individuals who use injection drugs (IDU) may have lower rates of adherence to highly active antiretroviral therapy (ART). However, previous studies of factors associated with adherence to ART among IDU have been limited primarily to samples drawn from clinical settings and in areas with financial barriers to healthcare.We evaluated patterns of ART adherence and rates of plasma HIV RNA response among a Canadian cohort of community-recruited IDU. Using data from a community-recruited cohort of antiretroviral-naive HIV-infected IDU, we investigated ART adherence patterns based on prescription refill compliance and factors associated with time to plasma HIV-1 RNA suppression (<500 copies/mL) using Cox proportional hazards regression in a setting with universal health care, including free ART. Between 1996 and 2008, 267 antiretroviral-naive HIV-infected IDU initiated ART and had a median of 51 months (inter-quartile range: 17-95 months) of follow-up. Overall, 81 (30.3%) were ≥95% adherent during the first year of HAART and 187 (70.0%) achieved HIV RNA suppression at least once over the study period, for an incidence-density of 34.5 (95% confidence interval [CI]: 29.8-39.9) per 100 person-years. The Kaplan-Meier cumulative plasma HIV RNA suppression rates at 12 months after the initiation of ART were 80.8% (95% CI: 71.2-88.7) for adherent and 28.9% (95% CI: 22.8-36.1) for non-adherent participants. While several socio-demographic characteristics and drug-using behaviours were identified as barriers to successful treatment in unadjusted analyses, the factor most strongly associated with time to HIV RNA suppression in multivariate analysis was adherence to ART of at least 95% (adjusted hazard ratio [AHR] = 6.0, 95% CI: 4.2-8.6, p<0.001). These results demonstrate low rates of adherence to ART among a community-recruited cohort of IDU and reinforce the importance of adherence as the key determinant of successful virological response to antiretroviral therapy.

We examined the impact of crystal methamphetamine injection on HIV RNA suppression among a prospective cohort of HIV-positive injection drug users initiating antiretroviral therapy. A multivariate Cox regression analysis found crystal methamphetamine injection to be negatively associated with viral load suppression (RH=0.63 [95% CI: 0.40-0.98]; p=0.039). This study is the first to our knowledge to demonstrate an association between crystal methamphetamine use and HIV RNA suppression., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

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.

Homelessness is prevalent among HIV-infected injection drug users (IDU) and may adversely affect access and adherence to antiretroviral therapy (ART). There are limited descriptions of the effect of homelessness on adherence to ART in long-term cohorts of HIV-infected IDU. We used data from a community-recruited prospective cohort of HIV-infected IDU, including comprehensive ART dispensation records, in a setting where HIV care is free. We examined the relationship between the homelessness measured longitudinally, and the odds of ≥95% adherence to ART using generalized estimating equations logistic regression modeling adjusting for sociodemographics, drug use, and clinical variables. Between May 1996 and September 2008, 545 HIV-infected IDU were recruited and eligible for the present study. The median follow-up duration was 23.8 months (IQR 8.5-91.6 months) contributing 2,197 person-years of follow-up. At baseline, homeless participants were slightly younger (35.8 vs. 37.9 years, p = 0.01) and more likely to inject heroin at least daily (37.1% vs. 24.6%. p = 0.004) than participants who had housing. The multivariate model revealed that homelessness (adjusted odds ratio [AOR] 0.66; 95% CI: 0.53-0.84) and frequent heroin use (AOR 0.40; 95% CI: 0.30-0.53) were significantly and negatively associated with ART adherence, whereas methadone maintenance was positively associated (AOR 2.33; 95% CI: 1.86-2.92). Sub-optimal ART adherence was associated with homelessness and daily injection heroin use among HIV-infected IDU. Given the survival benefit of ART, it is critical to develop and evaluate innovative strategies such as supportive housing and methadone maintenance to address these risk factors to improve adherence.

Background: Although some studies have identified impressive clinical gains for incarcerated HIV-seropositive injection drug users (IDUs) undergoing antiretroviral therapy (ART), the effect of incarceration on adherence to ART remains undetermined., Methods: We used data from a long-term community-recruited cohort of HIV-seropositive IDUs, including comprehensive ART dispensation records, in a setting where HIV care is free. We estimated the relationship between the cumulative burden of incarceration, measured longitudinally, and the odds of < 95% adherence to ART, with use of multivariate modeling., Results: From 1996 through 2008, 490 IDUs were recruited and contributed 2220 person-years of follow-up; 271 participants (55.3%) experienced an incarceration episode, with the number of incarcerations totaling 1156. In a multivariate model, incarceration had a strong dose-dependent effect on the likelihood of nonadherence to ART: 1-2 incarceration events (adjusted odds ratio [AOR], 1.49; 95% confidence interval [95% CI], 1.03-2.05), 3-5 events (AOR, 2.48; 95% CI, 1.62-3.65), and > 5 events (AOR, 3.11; 95% CI, 1.86-4.95)., Conclusions: Among HIV-seropositive IDUs receiving ART, an increasing burden of incarceration was associated with poorer adherence in a dose-dependent fashion. Our findings support improved adherence support for HIV-seropositive IDUs experiencing incarceration.

The delivery of antiretroviral therapy (ART) to injection drug users (IDU) may be influenced by provider concerns regarding the potential for increased HIV-related risk behavior following the initiation of HIV treatment. We evaluated whether ART initiation was associated with changes in syringe lending patterns among a long-term prospective cohort of HIV-positive IDU in Vancouver, Canada. Among 380 ART-naïve individuals eligible for this analysis, the median age was 34.2 (interquartile range [IQR] 27.7-40.8), 171 (45.0%) were female, and the median follow-up duration was 60 months (IQR=18-113). Between May 1996 and April 2008, 260 (68.4%) participants initiated ART. In a generalized linear mixed-effects model which compared each individual's likelihood of sharing syringes prior to and following the initiation of ART, syringe lending was not significantly associated with ART initiation in unadjusted (odds ratio=0.72, 95% CI: 0.38-1.36) or adjusted (odds ratio=0.78, 95% CI: 0.42-1.45) analyses. Concerns regarding increased injection risk behaviors following the initiation of ART were not observed in this setting., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

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., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Barriers to HIV treatment among injection drug users (IDU) are a major public health concern. However, there remain few long-term studies investigating key demographic and behavioral factors--and gender differences in particular--that may pose barriers to antiretroviral therapy (ART), especially in settings with universal healthcare. We evaluated access and adherence to ART in a long-term cohort of HIV-positive IDU in a setting where medical care and antiretroviral therapy are provided free of charge through a universal healthcare system., Methods: We evaluated baseline antiretroviral use and subsequent adherence to ART among a Canadian cohort of HIV-positive IDU. We used generalized estimating equation logistic regression to evaluate factors associated with 95% adherence to antiretroviral therapy estimated based on prescription refill compliance., Results: Between May 1996 and April 2008, 545 IDU participants were followed for a median of 23.8 months (Inter-quartile range: 8.5-91.6), among whom 341 (63%) were male and 204 (37%) were female. Within the six-month period prior to the baseline interview, 133 (39%) men and 62 (30%) women were on ART (p=0.042). After adjusting for clinical characteristics as well as drug use patterns measured longitudinally throughout follow-up, female gender was independently associated with a lower likelihood of being 95% adherent to ART (Odds Ratio [OR]=0.70; 95% Confidence Interval: 0.53-0.93)., Conclusions: Despite universal access to free HIV treatment and medical care, female IDU were less likely to access and adhere to antiretroviral therapy, a finding that was independent of drug use and clinical characteristics. These data suggest that interventions to improve access to HIV treatment among IDU must be tailored to address unique barriers to antiretroviral therapy faced by female IDU.

Cutaneous injection-related infections (CIRI), such as abscesses and cellulitis, are the cause of a substantial burden of morbidity and mortality among injection drug users (IDU). The possible contribution of exposure to correctional environments to CIRI risk has not been fully investigated. Thus, we sought to test the possible relationship between incarceration and CIRI using data from a community-based sample of IDU. Data for these analyses was from the Scientific Evaluation of Supervised Injecting (SEOSI) cohort, linked with administrative records of a local ED in Vancouver, Canada. Using longitudinal analysis we assessed the relationship between the number of ED visits for CIRI care and recent incarceration in a multivariate model including information on possible confounders. Between June 2004 and December 2006, 901 individuals were eligible for our analysis. Of these, 214 (9.6%) visited the ED for CIRI care at least once during the study period. The incidence of ED care for CIRI was 72.9 per 100 person years. In a multivariate model, recent incarceration was associated with a greater number of ED visits for CIRI care (adjusted relative rate = 1.56, 95% confidence interval: 1.31-1.85, P < 0.001). The need for ED treatment for CIRI was common among a sample of local IDU. Exposure to correctional environments was an independent risk factor for visiting the ED for CIRI care, suggesting improvements in infection control in local prisons is urgently needed.

Aims: To determine the total burden of illicit drug overdose mortality over the study period in the province of British Columbia and investigate possible population-level determinants by estimating rates among subgroups including First Nations individuals., Design: Review of coroner case files., Setting: The province of British Columbia, Canada., Participants: Individuals dying from an illicit drug overdose between 2001 and 2005., Measurements: Age-adjusted mortality rates, standardized mortality ratios (SMR) and years of potential life lost (YPLL), stratified by major population groups., Findings: Over the study period, 909 individuals died from illicit drug overdoses, including 104 (11.4%) First Nations individuals. Compared to the general population, First Nations males and females suffered from substantially elevated SMR and YPLL. In a multivariate logistic regression analysis, First Nations deaths were significantly more likely to be among women, related to injection drug use and to have occurred in the Downtown Eastside area of Vancouver, the local epicentre of human immunodeficiency virus infection and open drug use (all P< 0.05)., Conclusions: This report found highly elevated overdose death rates and levels of premature mortality among First Nations Canadians in British Columbia compared to the general population. While previously unidentified, these findings are consistent with the poorer population health profile of First Nations Canadians. Although further research is needed to identify the causes of the elevated death rates, our findings support increased availability of evidence-based overdose prevention measures., (© 2010 The Authors, Addiction © 2010 Society for the Study of Addiction.)

Objective: Although antiretroviral therapy (ART) dramatically reduces viral load and improves survival among HIV-infected injection drug users (IDUs), several short-term studies have raised concerns that ART initiation may result in increases in sexual risk behaviour among IDUs., Design: We used data from a long-running cohort of HIV-positive IDUs to examine whether ART initiation was associated with increases in several measures of sexual risk behaviour. The date of ART initiation was determined through a validated linkage to a centralized ART dispensation pharmacy., Methods: We used generalized linear mixed-effects modelling to examine whether sexual activity, unprotected intercourse, and multiple sexual partnerships were more likely in the 12-month period following ART initiation., Results: Among 457 individuals who were ART naive at baseline, the median age was 34 [interquartile range (IQR) 28-41] and 202 (44.2%) were women. Between May 1996 and April 2008, 260 (56.7%) participants initiated ART. In multivariate analyses, ART initiation was not associated with sexual activity [adjusted odds ratio (AOR) = 0.87, 95% confidence interval (CI) 0.60-1.25], unprotected intercourse (AOR = 0.82, 95% CI 0.51-1.31), or multiple sexual partnerships (AOR = 0.93, 95% CI 0.61-1.40)., Conclusion: In this study of HIV-positive IDUs, we failed to detect an increase in sexual risk behaviour during the period following ART initiation. In light of this evidence, and given the known positive effect of ART on survival and its potential role in reducing HIV transmission, concerns regarding potential increases in sexual risk-taking should not undermine the delivery of ART to IDUs.

Background: Treatment for drug addiction is effective in reducing the harms of injection drug use, including infection with HIV and/or hepatitis C. We sought to examine the prevalence and correlates of being unable to access addiction treatment in a representative sample of injection drug users randomly recruited from a supervised injection facility., Methods: Using generalized estimating equations, we determined the prevalence and factors associated with being unable to access addiction treatment., Results: Between 1 July 2004 and 30 June 2006, 889 individuals completed at least one interview and were included in this analysis. At each interview, approximately 20% of respondents reported trying but being unable to access any type of drug or alcohol treatment in the previous 6 months. Being unable to access treatment was independently associated with recent incarceration, daily use of heroin and borrowing used syringes. In a secondary question, the majority of individuals reported waiting lists were the reason for being unable to access treatment., Conclusion: Given the independent association between inability to access addiction treatment and elevated HIV risk behavior, these results suggest expanding addiction treatment may contribute significantly to HIV prevention efforts in this population.

Background: Although previous studies have identified high levels of drug-related harm in Thailand, little is known about illicit drug overdose experiences among Thai drug users. We sought to investigate non-fatal overdose experiences and responses to overdose among a community-recruited sample of injection drug users (IDU) in Bangkok, Thailand., Methods: Data for these analyses came from IDU participating in the Mit Sampan Community Research Project. The primary outcome of interest was a self-reported history of non-fatal overdose. We calculated the prevalence of past overdose and estimated its relationship with individual, drug-using, social, and structural factors using multivariate logistic regression. We also assessed the prevalence of ever witnessing an overdose and patterns of response to overdose., Results: These analyses included 252 individuals; their median age was 36.5 years (IQR: 29.0 - 44.0) and 66 (26.2%) were female. A history of non-fatal overdose was reported by 75 (29.8%) participants. In a multivariate model, reporting a history of overdose was independently associated with a history of incarceration (Adjusted Odds Ratio [AOR] = 3.83, 95% Confidence Interval [CI]: 1.52 - 9.65, p = 0.004) and reporting use of drugs in combination (AOR = 2.48, 95% CI: 1.16 - 5.33, p = 0.019). A majority (67.9%) reported a history of witnessing an overdose; most reported responding to the most recent overdose using first aid (79.5%)., Conclusions: Experiencing and witnessing an overdose were common in this sample of Thai IDU. These findings support the need for increased provision of evidence-based responses to overdose including peer-based overdose interventions.

Aims: Despite proven benefits of antiretroviral therapy (ART), many human immunodeficiency virus (HIV)-infected injection drug users (IDU) do not access treatment even in settings with free health care. We examined whether methadone maintenance therapy (MMT) increased initiation and adherence to ART among an IDU population with free health care., Design: We examined prospectively a cohort of opioid-using antiretroviral-naive HIV-infected IDU and investigated factors associated with initiation of antiretroviral therapy as well as subsequent adherence. Factors associated independently with time to first initiation of antiretroviral therapy were modelled using Cox proportional hazards regression., Findings: Between May 1996 and April 2008, 231 antiretroviral-naive HIV-infected opioid-using IDU were enrolled, among whom 152 (65.8%) initiated ART, for an incidence density of 30.5 [95% confidence interval (CI): 25.9-35.6] per 100 person-years. After adjustment for time-updated clinical characteristics and other potential confounders, use of MMT was associated independently with more rapid uptake of antiretroviral therapy [relative hazard = 1.62 (95% CI: 1.15-2.28); P = 0.006]. Those prescribed methadone also had higher rates of ART adherence after first antiretroviral initiation [odds ratio = 1.49 (95% CI: 1.07-2.08); P = 0.019]., Conclusion: These results demonstrate that MMT contributes to more rapid initiation and subsequent adherence to ART among opioid-using HIV-infected IDU. Addressing international barriers to the use and availability of methadone may increase dramatically uptake of HIV treatment among this population.

Background: The effect of ongoing illicit drug use on HIV treatment remains controversial, especially in countries where access to HIV treatment for active injection drug users (IDUs) is limited because of presumed non-adherence. We sought to investigate the influence of drug use patterns on adherence to antiretroviral therapy and virological suppression among IDUs., Methods: Using generalized estimating equation logistic regression, we explored the effect of abstinence versus ongoing drug use on adherence and virological suppression using data from a community-recruited cohort of IDUs in Vancouver (BC, Canada)., Results: A total of 381 HIV-positive IDUs were included in this analysis, among whom the median follow-up time was 30 months. In a multivariate model, no relationship was found between abstinence (reference) and active injection (adjusted odds ratio [AOR] 0.88, 95% confidence interval [CI] 0.65-1.17) and non-injection (AOR 0.97, 95% CI 0.67-1.41) drug use with adherence. In subanalyses, ongoing injection drug use was associated with a lower odds of virological suppression in comparison to abstinence (AOR 0.74, 95% CI 0.57-0.97; P=0.026) and both active IDUs and active non-IDUs had lower odds of virological suppression compared with abstinent participants when longer periods of virological suppression were considered., Conclusions: Given the absence of a strong relationship between abstinence and ongoing drug use and adherence among HIV-positive IDUs, programmes that restrict antiretrovirals to abstinent individuals should be re-examined. The lower rates of virological suppression associated with ongoing drug use nevertheless highlight the importance of comprehensive systems of care and addiction treatment for active drug users.

Background: Since 2003 Thailand has waged an aggressive "war on drugs" campaign focused on arresting and incarcerating suspected drug users and dealers. However, little is known about incarceration experiences among IDU in the wake of the recent war on drugs. Therefore, we sought to examine incarceration experiences among IDU in Bangkok, Thailand., Methods: We examined the prevalence of incarceration among community-recruited IDU participating in the Mitsampan Community Research Project. Multivariate logistic regression was used to identify factors associated with a self-reported history of incarceration. We also examined the prevalence of injection drug use and syringe sharing within prisons., Results: 252 IDU were recruited in August 2008; 66 (26.2%) were female and the median age was 36.5 years. In total, 197 (78.2%) participants reported a history of incarceration. In multivariate analyses, reporting a history of incarceration was associated with a history of compulsory drug treatment (adjusted odds ratio [AOR] = 4.93; 95% confidence interval [CI]: 1.95 - 12.48), non-fatal overdose (AOR = 3.69; 95%CI: 1.45 - 9.39), syringe sharing (AOR = 2.20; 95%CI: 1.12 - 4.32), and female gender (AOR = 0.41; 95%CI: 0.20 - 0.82). Among those who reported a history of incarceration, 59 (29.9%) reported injection drug use in prison, and 48 (81.4%) of these individuals reported sharing syringes in prison. Incarceration was not associated with the number of injections performed in the previous week (p = 0.202)., Conclusion: Over three-quarters of the IDU participating in this study reported a history of incarceration, and 30% of these individuals reported injection drug use within prison. Further, an alarmingly high level of syringe sharing within prison was reported, and incarceration was not associated with reductions in drug use. These findings provide further evidence of the need for community diversion strategies, as well as harm reduction programs, in Thai prisons.

Background: Given concerns over rising use of methamphetamine, especially among street-involved youth, and the links between exposure to the correctional system and the production of drug-related harm, we sought to assess the relationship between ever using methamphetamine and reporting ever being incarcerated in the At-Risk Youth Survey (ARYS) in Vancouver, Canada., Methods: The relationship between ever being imprisoned and ever using methamphetamine was estimated using a multivariate logistic regression analysis while also considering potentially confounding secondary demographic, social and behavioural variables., Results: Of the 478 youth recruited into ARYS between September 2005 and October 2006, 385 (80.5%) reported ever being incarcerated overnight or longer. In the multivariate model, methamphetamine use was independently associated with ever being incarcerated (Adjusted Odds Ratio: 1.79, 95% Confidence Interval [CI]: 1.03 - 3.13)., Conclusion: Incarceration was very common in this cohort and strongly linked with ever using methamphetamine. This finding is of concern and, along with the previously identified risks of drug-related harm associated with incarceration, supports the development of novel public policy, such as community-based drug treatment, to address the use of methamphetamine among street youth.

Background: While incarceration has consistently been associated with a higher risk of HIV infection for individuals who use injection drugs (IDU), the effect of incarceration on the post-release risk environment remains poorly described. We sought to assess the impact of incarceration on risk factors for HIV infection after release from prison in a sample of active IDU in Vancouver, Canada., Methods: Using a prospective cohort of community-recruited IDU followed from May 1, 1996 to November 30, 2005, we examined contingency tables and performed linear growth curve analyses to assess changes in the prevalence of independent risk factors for HIV infection from before to after a period of incarceration among participants reporting incarceration and a matched control group., Results: Of the 1603 participants followed-up over the study period, 147 (9.2%) were eligible for an analysis of post-incarceration risk behaviours and 742 (46.3%) were used as matched controls. Significant differences were found in one or both groups for the prevalence of frequent cocaine injection, requiring help injecting, binge drug use, residence in the HIV outbreak epicentre, sex-trade participation and syringe sharing (all p < 0.05) after incarceration. In linear growth curve adjusted for age, gender and ethnicity, syringe sharing was significantly more common in those recently released from prison (p = 0.03) than in the control group., Conclusion: In a sample of Canadian IDU, we did not observe any effect of incarceration on the prevalence of several behaviours that are risk factors for HIV infection, including intensity of drug use or participation in the sex trade. However, those recently released from prison were more likely to report syringe sharing that those in a matched control group.

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 McNemar's 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.

Background: Incarceration has been associated with a number of health-related harms among injection drug users (IDU). However, little is known about the prevalence and correlates of incarceration among community-based samples of IDU., Methods: We examined the prevalence and correlates of recent incarceration among IDU in the Scientific Evaluation of Supervised Injecting (SEOSI) cohort examined between 1 July 2004 and 30 June 2006 using generalised estimating equations (GEE)., Results: A total of 902 individuals were included in the analysis, of whom 255 (28.72%) were female and 536 (59.42%) reported a history of incarceration. In a multivariate GEE model, recent incarceration was associated positively and independently with a number of high-risk drug using behaviours, including syringe sharing., Conclusions: An alarmingly high proportion of active IDU reported recent incarceration and injecting while incarcerated. Recent incarceration was associated independently with syringe sharing. These findings add further evidence to repeated demands for an expansion of appropriate harm-reduction measures in Canada's prisons.

Background: Illicit drug overdose remains a leading cause of premature mortality in urban settings worldwide. We sought to estimate the number of deaths potentially averted by the implementation of a medically supervised safer injection facility (SIF) in Vancouver, Canada., Methodology/principal Findings: The number of potentially averted deaths was calculated using an estimate of the local ratio of non-fatal to fatal overdoses. Inputs were derived from counts of overdose deaths by the British Columbia Vital Statistics Agency and non-fatal overdose rates from published estimates. Potentially-fatal overdoses were defined as events within the SIF that required the provision of naloxone, a 911 call or an ambulance. Point estimates and 95% Confidence Intervals (95% CI) were calculated using a Monte Carlo simulation. Between March 1, 2004 and July 1, 2008 there were 1004 overdose events in the SIF of which 453 events matched our definition of potentially fatal. In 2004, 2005 and 2006 there were 32, 37 and 38 drug-induced deaths in the SIF's neighbourhood. Owing to the wide range of non-fatal overdose rates reported in the literature (between 5% and 30% per year) we performed sensitivity analyses using non-fatal overdose rates of 50, 200 and 300 per 1,000 person years. Using these model inputs, the number of averted deaths were, respectively: 50.9 (95% CI: 23.6-78.1); 12.6 (95% CI: 9.6-15.7); 8.4 (95% CI: 6.5-10.4) during the study period, equal to 1.9 to 11.7 averted deaths per annum., Conclusions/significance: Based on a conservative estimate of the local ratio of non-fatal to fatal overdoses, the potentially fatal overdoses in the SIF during the study period could have resulted in between 8 and 51 deaths had they occurred outside the facility, or from 6% to 37% of the total overdose mortality burden in the neighborhood during the study period. These data should inform the ongoing debates over the future of the pilot project.

Non-fatal overdose among injection drug users (IDU) is a source of significant morbidity. Since it has been suggested that supervised injecting facilities (SIF) may increase risk for overdose, we sought to evaluate patterns of non-fatal overdose among a cohort of SIF users. We examined recent non-fatal overdose experiences among participants enrolled in a prospective study of IDU recruited from within North America's first medically supervised safer injecting facility. Correlates of recent non-fatal overdoses were identified using generalized estimating equations (GEE). There were 1,090 individuals recruited during the study period of which 317 (29.08%) were female. At baseline, 638 (58.53%) reported a history of non-fatal overdose and 97 (8.90%) reported at least one non-fatal overdose in the last six months. This proportion remained approximately constant throughout the study period. In the multivariate GEE analysis, factors associated with recent non-fatal overdose included: sex-trade involvement (Adjusted Odds Ratio [AOR]: 1.45 [95% Confidence Interval [CI] 1.07-1.99], p = 0.02) and public drug use (AOR: 1.50 [95% CI 1.09-2.06]; p = 0.01). Using the SIF for >or= 75% of injections was not associated with recent non-fatal overdose in univariate (Odds Ratio: 1.05, p = 0.73) or multivariate analyses (AOR: 1.01, p = 0.96). The proportion of individuals reporting recent non-fatal overdose did not change over the study period. Our findings indicate that a sub-population of IDU might benefit from overdose prevention interventions. Our findings refute the suggestion that the SIF may increase the likelihood of overdose.