Role of primary T-cell immunodeficiency and hepatitis B coinfection on spontaneous clearance of hepatitis C: The BC Hepatitis Testers Cohort.

T-cell host immune response against hepatitis C virus (HCV) has been suggested to play an important role in determining HCV infection outcome. However, data from human studies are not available. This study examined the effect of primary T-cell deficiency along with other factors on the spontaneous clearance of HCV in a large population-based cohort in British Columbia, Canada. The BC Hepatitis Testers Cohort includes all individuals tested for HCV in BC in 1990-2013 linked with data on their medical visits, hospitalizations and prescription drugs. HCV-positive individuals with at least one valid HCV PCR test on/after HCV diagnosis (n=46 783) were included in this study. To examine factors associated with the spontaneous clearance of HCV, multivariable logistic regression was fitted on the full sample, and Cox proportional hazards model on the HCV seroconverters. Spontaneous clearance was observed in 25.1% (n=11 737) of those tested for HCV. After adjusting for potential confounders, the odds of spontaneous clearance of HCV was lower in people with primary T-cell immunodeficiency (adjusted odds ratio [aOR]: 0.55, 95% CI: 0.32-0.94), and higher in females (aOR: 1.61, 95% CI: 1.54-1.68) and in those coinfected with HBV (aOR: 2.31, 95% CI: 1.93-2.77). Similar results were observed in HCV seroconverters except HBV coinfection was not significant. In conclusion, primary T-cell immunodeficiency is associated with a lower spontaneous clearance of HCV while female sex and coinfection with HBV are associated with a higher spontaneous clearance.

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.

Impact of hepatitis C virus infection on all-cause and liver-related mortality in a large community-based cohort of inner city residents.

The aim of this study was to measure the impact of hepatitis C virus (HCV) infection on mortality in a cohort of inner city residents. The Community Health and Safety Evaluation is a community-based study of inner city residents followed retrospectively and prospectively through linkages with provincial virology and mortality databases. We identified participants having received HCV antibody testing, evaluated cause-specific mortality rates and factors associated with all-cause and liver-related mortality using Cox Proportional Hazards models. Overall, 2332 participants received HCV antibody testing (recent non-injection drug use - 81%). The prevalence of HCV and HIV was 64% (1495 of 2332) and 21% (485 of 2332), respectively. Between January 2003 and December 2007, there were 180 deaths (192 per 10.000 person-years; 95% CI: 165, 222), with 21% HIV-related, 20% drug-related and 7% liver-related. Mortality was associated with age >50 [adjusted hazard ratio (AHR) 2.80 vs < 40 years (referent group); 95% CI 1.93, 4.07, P < 0.001] and HIV infection (AHR 3.81; 95% CI 2.72, 5.34, P < 0.001), but not positive HCV antibody status (AHR 1.19; 95% CI 0.83, 1.72, P = 0.35). Liver-related mortality was associated with age >50 [AHR 18.49 vs < 40 years (referent group); 95% CI 2.27, 150.41, P < 0.001] and positive HCV antibody status (AHR 7.69; 95% CI 0.99, 59.98, P = 0.052). This study demonstrates a high rate of mortality in this population, particularly those with HIV. HCV-infected inner city residents >50 years of age were at significant risk of liver-related mortality. Continued surveillance of this population infected with HCV in the 1970s and 1980s is important.

Community-associated methicillin-resistant Staphylococcus aureus is prevalent in wounds of community-based injection drug users.

Injection drug users (IDUs) have an elevated risk for carriage of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). Cutaneous injection-related infections are common in IDUs but detailed studies are few. Based on a subsample of 218 individuals from a community-recruited cohort of IDUs at a supervised injection facility, we investigated the microbiology and related antibiotic susceptibility profiles of isolates from 59 wounds. Twenty-seven percent of subjects had at least one wound and 25 (43%) were culture positive for S. aureus alone [14 MRSA and 11 (19%) methicillin-susceptible (MSSA) isolates]. Sixteen of 18 MRSA isolates were classified as community associated (CA) by the presence of genes encoding for PVL. MRSA and MSSA occurred in mixed infection with other organisms on three and six occasions, respectively. All CA-MRSA isolates were susceptible to tetracycline, vancomycin and linezolid but only 13% were susceptible to clindamycin compared to 63% of MSSA isolates. The frequency of CA-MRSA is a cause for concern in wound infection in the IDU setting.

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.

Low uptake of treatment for hepatitis C virus infection in a large community-based study of inner city residents.

Despite the availability of effective therapy for hepatitis C virus (HCV) infection, there are little data on the uptake of treatment. We evaluated factors associated with HCV infection and the uptake of HCV treatment in a large community-based inner city cohort in Vancouver, Canada. The Community Health and Safety Evaluation is a cohort study of inner city residents recruited from January 2003 to June 2004. HIV and HCV status and information on prescriptions for HCV treatment were determined through linkage with provincial databases. HCV prevalence was calculated and factors associated with HCV infection were identified. HCV treatment uptake and incidence of HCV infection from January 2000 to December 2004 were expressed in terms of person-years of observation. Among 2913 individuals, HCV antibody testing was performed in 2118 and the HCV seroprevalence was 64.2% (1360 of 2118). In total, 1.1% of HCV antibody-positive individuals (15 of 1360) initiated treatment for HCV infection from January 2000 to December 2004 [0.28 cases per 100 person-years (95% CI, 0.15-0.46)]. Three of 15 (20.0%) treated individuals achieved a sustained virological response. During the same period, the incidence of HCV infection was 7.26 cases (95% CI, 5.72-8.80) per 100 person-years. Overall, the rate of new HCV seroconversions in this cohort in the study period was about 25 times the rate of HCV treatment uptake. There are extremely low rates of HCV treatment initiation and very limited effectiveness, despite a high prevalence of HCV infection in this large community-based cohort of inner city residents with access to universal healthcare.

Condom use among injection drug users accessing a supervised injecting facility.

OBJECTIVES: Although supervised injecting facility (SIF) use has been associated with reductions in injection-related risk behaviours, the impact of SIFs on the sexual behaviour of injection drug users (IDUs) has not been thoroughly investigated. Therefore, we examined the patterns and predictors of condom use among SIF users in Vancouver, Canada. METHODS: We performed a longitudinal analysis of the factors associated with consistent condom use among IDUs recruited from within a SIF. RESULTS: Among 1090 individuals, 650 (59.6%) reported a sexual partner in the past 6 months at baseline. Consistent condom use was reported by 108 (25.3%) and 205 (61.6%) individuals reporting regular or casual partners, respectively. After 2 years of observation, these proportions increased to 32.9% and 69.8%, respectively. In multivariate analysis, predictors of consistent condom use with regular partners included HIV positivity (adjusted odds ratio (AOR) 2.23; 95% CI 1.51 to 3.31), injecting with a sex partner (AOR 0.50; 95% CI 0.37 to 0.68), enrollment in addiction treatment (AOR 0.68, 95% CI 0.52 to 0.89) and time since recruitment (AOR 1.29; 95% CI 1.06 to 1.55 per year). Predictors of consistent condom use with casual partners included HIV positivity (AOR 1.70; 95% CI 1.03 to 2.81), syringe borrowing (AOR 0.54; 95% CI 0.32 to 0.91) and syringe lending (AOR 0.52; 95% CI 0.32 to 0.84). CONCLUSIONS: Our results demonstrate that among SIF users, consistent condom use was more frequent among casual sex partners and among HIV positive individuals. Importantly, while the prevalence of consistent condom use was low at baseline, it increased over time. Our findings suggest a possible beneficial effect of the SIF on safer sexual practices.

Drug sharing with clients as a risk marker for increased violence and sexual and drug-related harms among survival sex workers.

Previous studies have described links between violence, decreased condom use and drug sharing among intimate partners, though limited information exists about the predictors of drug sharing among female sex workers and their clients. The following analysis explored the association between sharing illicit drugs with clients and sexual and drug-related harms among survival sex workers. A total of 198 women participated in interview-administered questionnaires and confidential HIV testing. Of the total, 117 (59%) reported sharing drugs with clients/johns in the last six months and crack cocaine was the primary drug shared (n=108). In logistic regression analysis, sharing drugs with clients/johns was associated with borrowing a used crack pipe (AOR=5.63; 95%CI: 2.71-9.44; p<0.001), intensive/daily crack cocaine smoking (AOR=3.78; 95%CI:1.60-8.92; p<0.002), inconsistent condom use by a client/john (AOR=3.17; 95%CI:1.48-6.77; p<0.003) and having a recent bad date (verbal harassment, physical and/or sexual assault) (AOR=2.71; 95%CI:1.17-6.32; p=0.021). Sharing illicit drugs with clients/johns may be a crucial risk marker for increased violence and sexual and drug-related harms among survival sex workers. HIV prevention and harm reduction initiatives targeting both women and clients/johns are urgently needed, including enhanced support for community and peer-driven sex work initiatives, to address some of the structural facilitators for HIV transmission.

Mapping violence and policing as an environmental-structural barrier to health service and syringe availability among substance-using women in street-level sex work.

BACKGROUND: Within street-based sex work and substance-using populations, there is growing evidence to support the role of place, both physical setting and social meanings attached to place, in mediating the effectiveness and reach of health and harm reduction services. METHODS: Social mapping was used to explore how health service and syringe availability may be impacted at the geographic level by avoidance of physical settings due to violence and policing among women in street-level sex work. Through a community-based research partnership and extensive peer-led outreach over a 6-month period, women were invited to participate in interview-questionnaires and mapping of their community, working conditions, and access to resources. Results were compiled used ArcGIS software and GIS street maps. In secondary analysis, logistic regression was used to model the geographic association (using likelihood ratio and significance at p<0.05) and stratified models were run to assess differential patterns of avoidance based on age, ethnicity and drug use. RESULTS: The findings reveal a significant geographic relationship between a heavily concentrated core area of health and syringe availability and avoidance of physical settings due to violence and policing by 198 women in street-level sex work in Vancouver, Canada. Of particular concern, this correlation is significantly elevated among younger and Aboriginal women, active injection drug users, and daily crack cocaine smokers, suggesting significant environmental-structural barriers to interventions among these vulnerable populations. CONCLUSIONS: The resultant displacement of sex work to primarily industrial settings and side streets pushes women further from health and social supports and reduces access to safer injection and drug use paraphernalia. This study offers important evidence for environmental-structural level prevention and safer environment interventions, supported by legal reforms, that facilitate safer sex work environments, including spatial programming, peer-based prevention, outreach and mobile resources, and peer-supervised safer sex work settings.

Prevalence and correlates of hepatitis C infection among users of North America's first medically supervised safer injection facility.

BACKGROUND: North America's first medically supervised safer injection facility (SIF) for illicit drug users was opened in Vancouver, Canada on 22 September 2003. We examined the prevalence and correlates of hepatitis C (HCV) infection among a representative cohort of SIF users. METHODS: Users of the Vancouver SIF were selected at random and asked to enrol in the Scientific Evaluation of Supervised Injecting (SEOSI) cohort. At baseline, venous blood samples were collected and an interviewer-administered questionnaire was performed. Participants who were HCV-positive were compared with HCV-negative subjects using bivariate and logistic regression analyses. RESULTS: Between 1 December 2003 and 30 July 2004, 691 participants were enrolled into the SEOSI cohort, among whom 605 (87.6%) were HCV-positive at baseline. Factors independently associated with HCV infection in logistic regression analyses included: involvement with the sex trade [adjusted odds ratio (AOR) 3.7, 95% confidence interval (CI) 2.1-6.1], history of borrowing syringes (AOR 1.8, 95%CI 1.1-2.9), and history of incarceration (AOR 2.6, 95%CI 1.5-4.4). Daily heroin use was protective against HCV infection (AOR 0.6, 95%CI 0.3-0.9). CONCLUSION: The SIF has attracted injection drug users with a high burden of HCV infection and a substantial proportion of uninfected individuals. Although cross-sectional, this study provides some insight into historical risks for HCV infection among this population, and prospective follow-up of this cohort will be useful to determine if use of the SIF is associated with reduced risk behaviour and HCV incidence.

High rates of primary care and emergency department use among injection drug users in Vancouver.

BACKGROUND: Frequent use of emergency rooms by injection drug users (IDUs) has been attributed to a lack of access to primary care and barriers to health services. Using a community-based sample of IDUs, we examined rates of primary care and emergency room use among IDUs and identified correlates of frequent emergency department use. METHODS: From January to November 2003, we enrolled IDUs into a prospective cohort study involving a baseline questionnaire, comprehensive retrospective and prospective health record linkages. We examined rates of primary care and emergency department utilization, and diagnoses upon arrival in the emergency room. Logistic regression was used to determine factors independently associated with frequent emergency room use. RESULTS: Of the 883 IDUs included in this analysis, 687 (78 per cent) accessed a primary care clinic in the previous year, while 528 (60 per cent) participants accessed the emergency room (ER) during the years 2002 and 2003. Abscesses, cellulitis and other skin infections accounted for the greatest proportion of ER use. Factors independently associated with frequent ER use included: frequent crystal methamphetamine injection (AOR = 2.4, 95 per cent CI: 1.0-5.6); non-fatal overdose (AOR = 2.1, 95 per cent CI: 1.4-3.3); HIV-positive status (AOR = 1.5, 95 per cent CI: 1.1-2.1), having been physically assaulted (AOR = 1.5, 95 per cent CI: 1.1-2.1); and primary care utilization (AOR = 1.5, 95 per cent CI: 1.0-2.1). DISCUSSION: high rates of ER use were observed among IDUs, despite high rates of primary care use among this same population. ER use was due primarily to preventable injection-related complications that are less amenable to primary care interventions, and therefore educational and prevention efforts that encourage and enable sterile injection practices should be promoted.

Surviving the sex trade: a comparison of HIV risk behaviours among street-involved women in two Canadian cities who inject drugs.

In Canada, very little is known about the factors and processes that cause drug-related harm among female intravenous drug users (IDUs). Women who inject drugs and participate in the survival sex trade are considered to be at increased risk for sexual and drug-related harms, including HIV infection. Between September 1999 and September 2000, women participating in the VIDUS cohort in Vancouver and the St. Luc Cohort in Montreal completed interviewer-administered questionnaires. Analyses were conducted to compare the demographic characteristics, sexual risk behaviours, risky injection practices and drug use patterns among women who self-identified as participating in the sex trade with those who did not identify as participating in the sex trade. Logistic regression was used to identify factors independently associated with exchanging sex for money or drugs. HIV prevalence at the study visit (September 1999-2000) was 29% for sex trade workers and 29.2% for non-sex trade workers. While patterns of sexual risk were similar, the risky injection practice and drug use patterns between sex trade workers and non-sex trade workers were markedly different. Logistic regression analysis of cross-sectional data revealed that independent behaviours associated with the sex trade included: greater than once per day use of heroin (adjusted OR 2.7), smokeable crack cocaine (adjusted OR = 3.3) and borrowing used syringes (adjusted OR = 2.0). Creative, client-driven interventions are urgently needed for women who trade sex for money or for drugs.

High pregnancy rates and reproductive health indicators among female injection-drug users in Vancouver, Canada.

OBJECTIVE: To determine the incidence of pregnancy among active injection-drug users and to identify factors associated with becoming pregnant. METHODS: The Vancouver Injection Drug User Study (VIDUS) is a prospective cohort study that began in 1996. Women who had completed a baseline and at least one follow-up questionnaire between June 1996 and January 2002 were included in the study. Parametric and non-parametric methods were used to compare characteristics of women who reported pregnancy over the study period with those who did not over the same time period. RESULTS: A total of 104 women reported a primary pregnancy over the study period. The incidence of pregnancy over the follow-up period was 6.46 (95% confidence interval (CI) 5.24-7.87) per 100 person-years. The average age of women who reported pregnancy was younger than that of women who did not report pregnancy (27 vs. 32 years, p < 0.001). Women of Aboriginal ethnicity were more likely to report pregnancy (odds ratio 1.6, 95% CI 1.0-2.5). Comparison of drug use showed no significant differences in pregnancy rate with respect to the use of heroin, cocaine or crack (p > 0.05). In examining sexual behavior, women who reported having had a regular partner in the previous 6 months were three times more likely to have reported pregnancy. Despite the fact that 67% of women in this study reported using some form of contraception, the use of reliable birth control was low. Only 5% of women in our study reported the use of hormonal contraceptives. CONCLUSION: There were a high number of pregnancies among high-risk women in this cohort. This corresponded with very low uptake of reliable contraception. Innovative strategies to provide reproductive health services to at-risk women who are injecting drugs is a public health priority.

Risky sexual behaviours among injection drugs users with high HIV prevalence: implications for STD control.

Injection drug use is inextricably linked to commercial sex work and the transmission of sexually transmitted disease (STD). In many communities prevention efforts have been stalled owing to the marginal existence of this community. This study describes the sexual activities, condom use, reported STDs, and commercial sex work in a large cohort of injection drug users. Seventy two per cent of male and 92% of female subjects in the cohort were sexually active. Among female subjects, 57% reported more than 100 lifetime partners. Condoms were generally not used with regular partners, used about half the time with casual partners, and used about 80% of the time with paying partners. Female sex workers were more likely to have unstable housing and to report incarceration in the previous six months. Reducing the transmission of STDs and HIV in drug using communities is a public health priority. While existing prevention programmes should be strengthened, innovative approaches to STD surveillance, diagnosis, and prevention are needed.

Impact of HIV infection on mortality in a cohort of injection drug users.

The prevalence of HIV has been rising among injection drug users (IDUs) and AIDS is now an important cause of death among that population. We tracked mortality and recorded detailed causes of death in the Vancouver Injection Drug Users Study (VIDUS). This is an open cohort of over 1,400 active IDUs that began in May 1996. At enrollment and at semiannual follow-up visits, a trained interviewer administers a detailed semistructured questionnaire. Mortality was recorded during follow-up and detailed causes of death were collected from coroner's reports, hospital records, and the provincial (British Columbia) registry. Causes of death were obtained on 125 participants. Overall, the leading cause of death was overdose accounting for 25% of deaths among HIV-positive participants and 42% among HIV-negative participants. Of the 65 deaths among HIV-positive individuals, 22 (34%) were HIV related. Mortality was associated with older age (adjusted hazards ratio [AHR], 1.03 per year), HIV positivity (AHR, 2.67), injection cocaine use (AHR, 2.23) and methadone treatment (AHR, 0.47). The high rate of HIV in this population has added significantly to the burden of illness and death in this marginalized population.

Incidence of hepatitis C virus infection among injection drug users during an outbreak of HIV infection.

BACKGROUND: Beginning in 1994, Vancouver experienced an explosive outbreak of HIV infection among injection drug users (IDUs). The objectives of this study were to measure the prevalence and incidence of hepatitis C virus (HCV) infection in this context and to examine factors associated with HCV seroconversion among IDUs. METHODS: IDUs recruited through a study site and street outreach completed interviewer-administered questionnaires covering subjects' characteristics, behaviour, health status and service utilization and underwent serologic testing for HIV and HCV at baseline and semiannually thereafter. A Cox proportional hazards model was used to identify independent correlates of HCV seroconversion. RESULTS: As of Nov. 30, 1999, 1345 subjects had been recruited into the study cohort. The prevalence of anti-HCV antibodies was 81.6% (95% confidence interval [CI] 79.6% to 83.6%) at enrollment. Sixty-two HCV seroconversions occurred among 155 IDUs who were initially HCV negative and who returned for follow-up, for an overall incidence density rate of 29.1 per 100 person-years (95% CI 22.3 to 37.3). The HCV incidence remained above 16 per 100 person-years over 3 years of observation (December 1996 to November 1999), whereas HIV incidence declined from more than 19 to less than 5 per 100 person-years. Independent correlates of HCV seroconversion included female sex, cocaine use, injecting at least daily and frequent attendance at a needle exchange program. INTERPRETATION: Because of high transmissibility of HCV among those injecting frequently and using cocaine, the harm reduction initiatives deployed in Vancouver during the study period proved insufficient to eliminate hepatitis C transmission in this population.

Unsafe injection practices in a cohort of injection drug users in Vancouver: could safer injecting rooms help?

BACKGROUND: In several European countries safer injecting rooms have reduced the public disorder and health-related problems of injection drug use. We explored factors associated with needle-sharing practices that could potentially be alleviated by the availability of safer injecting rooms in Canada. METHODS: The Vancouver Injection Drug User Study is a prospective cohort study of injection drug users (IDUs) that began in 1996. The analyses reported here were restricted to the 776 participants who reported actively injecting drugs in the 6 months before the most recent follow-up visit, during the period January 1999 to October 2000. Needle sharing was defined as either borrowing or lending a used needle in the 6-month period before the interview. RESULTS: Overall, 214 (27.6%) of the participants reported sharing needles during the 6 months before follow-up; 106 (13.7%) injected drugs in public, and 581 (74.9%) reported injecting alone at least once. Variables independently associated with needle sharing in a multivariate analysis included difficulty getting sterile needles (adjusted odds ratio [OR] 2.7, 95% confidence interval [CI] 1.8-4.1), requiring help to inject drugs (adjusted OR 2.0, 95% CI 1.4-2.8), needle reuse (adjusted OR 1.8, 95% CI 1.3-2.6), frequent cocaine injection (adjusted OR 1.6, 95% CI 1.1-2.3) and frequent heroin injection (adjusted OR 1.5, 95% CI 1.04-2.1). Conversely, HIV-positive participants were less likely to share needles (adjusted OR 0.5, 95% CI 0.4-0.8), although 20.2% of the HIV-positive IDUs still reported sharing needles. INTERPRETATION: Despite the availability of a large needle-exchange program and targeted law enforcement efforts in Vancouver, needle sharing remains an alarmingly common practice in our cohort. We identified a number of risk behaviours--difficulty getting sterile needles, needle sharing and reuse, injection of drugs in public and injecting alone (one of the main contributing causes of overdose)--that may be alleviated by the establishment of supervised safer injecting rooms.

Hospital utilization and costs in a cohort of injection drug users.

BACKGROUND: Many injection drug users (IDUs) seek care at emergency departments and some require hospital admission because of late presentation in the course of their illness. We determined the predictors of frequent emergency department visits and hospital admissions among community-based IDUs and estimated the incremental hospital utilization costs incurred by IDUs with early HIV infection relative to costs incurred by HIV-negative IDUs. METHODS: The Vancouver Injection Drug User Study (VIDUS) is a prospective cohort study involving IDUs that began in 1996. Our analyses were restricted to the 598 participants who gave informed consent for our study. We used the participants' responses to the baseline VIDUS questionnaire and, from medical records at St. Paul's Hospital, Vancouver, we collected detailed information about the frequency of emergency department visits, hospital admissions and the primary diagnosis for all visits or hospital stays between May 1, 1996, and Aug. 31, 1999. The incremental difference in hospital utilization costs by HIV status was estimated, based on 105 admissions in a subgroup of 64 participants. RESULTS: A total of 440 (73.6%) of the 598 IDUs made 2763 visits to the emergency department at St. Paul's Hospital during the study period. Of these 440, 265 (160.2%) made frequent visits (3 or more). The following factors were associated with frequent use: HIV-positive status (seroprevalent: adjusted odds ratio [OR] 1.7, 95% confidence interval [CI] 1.2-2.6; seroconverted during study period: adjusted OR 3.0, 95% CI 1.6-5.7); more than 4 injections daily (adjusted OR 1.5, 95% CI 1.1-2.1); cocaine use more frequent than use of other drugs (adjusted OR 2.0, 95% CI 1.2-3.6); and unstable housing (adjusted OR 1.5, 95% CI 1.1-2.2). During the study period 210 of the participants were admitted to hospital 495 times; 118 (56.2%) of them were admitted frequently (2 or more admissions). The 2 most common reasons for admission were pneumonia (132 admissions among 79 patients) and soft-tissue infections (cellulitis and skin abscess) (90 admissions among 59 patients). The following factors were independently associated with frequent hospital admissions: HIV-positive status (seroprevalent: adjusted OR 5.4, 95% CI 3.4-8.6; seroconverted during study period: adjusted OR 2.9, 95% CI 1.4-6.0); and female sex (adjusted OR 1.8, 95% CI 1.1-3.1). The incremental hospital utilization costs incurred by HIV-positive IDUs relative to the costs incurred by HIV-negative IDUs were $1752 per year. INTERPRETATION: Hospital utilization was significantly higher among community-based IDUs with early HIV disease than among those who were HIV negative. Much of the hospital use was related to complications of injection drug use and may be reduced with the establishment of programs that integrate harm reduction strategies with primary care and addiction treatment.

Antiretroviral medication use among injection drug users: two potential futures.

OBJECTIVE: To model the potential impact of HIV infection rates and the use of antiretroviral medication on life expectancy and mortality in the Downtown Eastside of Vancouver, British Columbia, Canada, from 1999 to 2006. DESIGN: Population projections were made to estimate the population of the Downtown Eastside in the year 2006. METHODS: Two scenarios were modelled to predict the impact of HIV infection and antiretroviral use on mortality and life expectancy. The use of antiretroviral therapy was estimated to be 80% in the first scenario and 20% in the second. The prevalence of HIV by age and sex, and by year infected was estimated using data from the Vancouver Injection Drug User Study. RESULTS: If the level of antiretroviral therapy use among HIV-positive individuals was 80% at baseline, then we estimate that the life expectancy at birth in the year 2006 will be 60.8 years for men and 72.8 years for women, and 172 AIDS deaths will occur between 1999 and 2006. In contrast, if the present level of antiretroviral medication use persists, the life expectancy at birth in the year 2006 will be 56.9 years for men and 68.6 years for women, and 503 AIDS deaths will occur between 1999 and 2006. CONCLUSION: Our analysis suggests that if the low levels of antiretroviral therapy use persist, life expectancy in Vancouver's Downtown Eastside will soon be on a par with many of the world's least developed countries. Our findings highlight the large health status decline that can be expected in many inner city neighbourhoods if low levels of antiretroviral use persist. Although reasonable coverage targets for injection drug users (IDU) have not been established, the expanded use of antiretroviral medication is urgently needed to avert a drastic decline in health status.

Extent to which low-level use of antiretroviral treatment could curb the AIDS epidemic in sub-Saharan Africa.

BACKGROUND: Despite growing international pressure to provide HIV-1 treatment to less-developed countries, potential demographic and epidemiological impacts have yet to be characterised. We modelled the future impact of antiretroviral use in South Africa from 2000 to 2005. METHODS: We produced a population projection model that assumed zero antiretroviral use to estimate the future demographic impacts of the HIV-1 epidemic. We also constructed four antiretroviral-adjusted scenarios to estimate the potential effect of antiretroviral use. We modelled total drug cost, cost per life-year gained, and the proportion of per-person health-care expenditure required to finance antiretroviral treatment in each scenario. FINDINGS: With no antiretroviral use between 2000 and 2005, there will be about 276,000 cumulative HIV-1-positive births, 2,302,000 cumulative new AIDS cases, and the life expectancy at birth will be 46.6 years by 2005. By contrast, 110,000 HIV-1-positive births could be prevented by short-course antiretroviral prophylaxis, as well as a decline of up to 1 year of life expectancy. The direct drug costs of universal coverage for this intervention would be US$54 million--less than 0.001% of the per-person health-care expenditure. In comparison, triple-combination treatment for 25% of the HIV-1-positive population could prevent a 3.1-year decline in life expectancy and more than 430,000 incident AIDS cases. The drug costs of this intervention would, however, be more than $19 billion at present prices, and would require 12.5% of the country's per-person health-care expenditure. INTERPRETATION: Although there are barriers to widespread HIV-1 treatment, limited use of antiretrovirals could have an immediate and substantial impact on South Africa's AIDS epidemic.