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Biomedical subjects

Mark W Tyndall

Publications and source records attributed to Mark W Tyndall.

At least 19 recordsLinked to original sources
PubMed2006

HIV seroprevalence among participants at a Supervised Injection Facility in Vancouver, Canada: implications for prevention, care and treatment.

North America's first government sanctioned medically supervised injection facility (SIF) was opened during September 2003 in Vancouver, Canada. This was in response to a large open public drug scene, high rates of HIV and hepatitis C transmission, fatal drug overdoses, and poor health outcomes among the city's injection drug users. Between December 2003 and April 2005, a representative sample of 1,035 SIF participants were enrolled in a prospective cohort that required completing an interviewer-administered questionnaire and providing a blood sample for HIV testing. HIV infection was detected in 170/1007 (17%) participants and was associated with Aboriginal ethnicity (adjusted Odds Ratio [aOR], 2.70, 95% Confidence Interval [95% CI], 1.84-3.97), a history of borrowing used needles/syringes (aOR, 2.0, 95% CI, 1.37-2.93), previous incarceration (aOR, 1.87, 95% CI, 1.11-3.14), and daily injection cocaine use (aOR, 1.42, 95% CI, 1.00-2.03). The SIF has attracted a large number of marginalized injection drug users and presents an excellent opportunity to enhance HIV prevention through education, the provision of sterile injecting equipment, and a supervised environment to self-inject. In addition, the SIF is an important point of contact for HIV positive individuals who may not be participating in HIV care and treatment.

Journal Article↗
PubMed2006

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.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Injection drug users' perceptions regarding use of a medically supervised safer injecting facility.

BACKGROUND: In recent years, there has been increased interest in supervised safer injecting facilities (SIF) as a strategy to reduce the harms of illicit drug use; however, little work has been done to assess drug users' satisfaction with this service. This study was undertaken to explore injection drug users' experiences and opinions regarding North America's first SIF in Vancouver, Canada. METHODS: Injection drug users (IDU) were randomly recruited from within the Vancouver SIF and invited to enroll in the Scientific Evaluation of Supervised Injecting (SEOSI) cohort. For the present study, participants were then surveyed regarding their experiences and beliefs regarding the SIF. RESULTS: Of 1082 IDU surveyed, 809 (75%) reported that their injecting behavior had changed as a result of using the SIF. Among these individuals, 80% indicated that the SIF had resulted in less rushed injecting, 71% indicated that the SIF had led to less outdoor injecting and 56% reported less unsafe syringe disposal. The three most common features always or usually limiting IDU's use of the SIF were: travel to the SIF (12%), limited operating hours (7%), and waiting times to access the SIF (5%). When asked in what ways the SIF might be improved, the three most common suggestions were: longer hours of operation (53%), addition of a washroom (51%), and reduced waiting times (46%). CONCLUSIONS: Many IDU reported changes in their injecting behaviors that have important implications for community and public health. Addressing a number of programmatic issues related to operating hours and waiting times, and the provision of additional amenities within SIF, may help to further improve their impact.

Adult↗
PubMed2006

Impact of a medically supervised safer injecting facility on drug dealing and other drug-related crime.

North America's first medically supervised safer injecting facility (SIF) recently opened in Vancouver, Canada. One of the concerns prior to the SIF's opening was that the facility might lead to a migration of drug activity and an increase in drug-related crime. Therefore, we examined crime rates in the neighborhood where the SIF is located in the year before versus the year after the SIF opened. No increases were seen with respect to drug trafficking (124 vs. 116) or assaults/robbery (174 vs. 180), although a decline in vehicle break-ins/vehicle theft was observed (302 vs. 227). The SIF was not associated with increased drug trafficking or crimes commonly linked to drug use.

British Columbia↗
PubMed2006

Service uptake and characteristics of injection drug users utilizing North America's first medically supervised safer injecting facility.

In 2003, the city of Vancouver, British Columbia, opened North America's first government-sanctioned safer injecting facility, where injection drug users (IDUs) can inject preobtained illicit drugs under the supervision of nurses. Use of the service by IDUs was followed by measurable reductions in public drug use and syringe sharing. IDUs who are frequently using the program tend to be high-intensity cocaine and heroin injectors and homeless individuals. The facility has provided high-risk IDUs a hygienic space where syringe sharing can be eliminated and the risk of fatal overdose reduced. Ongoing evaluation will be required to assess its impact on overdose rates and HIV infection levels, as well as its ability to improve IDU contact with medical care and addiction treatment.

Ambulatory Care Facilities↗
PubMed2006

Antiretroviral adherence and HIV treatment outcomes among HIV/HCV co-infected injection drug users: the role of methadone maintenance therapy.

OBJECTIVE: We examined the association of methadone maintenance therapy (MMT) with highly active antiretroviral therapy (HAART) adherence and HIV treatment outcomes among a cohort of HIV/HCV co-infected injection drug users (IDUs). METHODS: We obtained demographic, drug use, and addiction care history from the Vancouver Injection Drug User Study (VIDUS), which is an open cohort study of IDUs. The questionnaires were longitudinally linked to the British Columbia HIV/AIDS Drug Treatment Program to obtain HAART adherence and HIV treatment outcome data. There were 278 VIDUS participants who accessed HAART from August 1, 1996 to November 24, 2003. We constructed longitudinal logistic models using generalized estimating equations to examine the independent associations between methadone maintenance therapy and the following outcomes: HAART adherence; plasma HIV-1 RNA suppression; and CD4 cell rise of 100cells/mm(3). RESULTS: Among participants who reported at least weekly heroin use, MMT was independently associated with lower odds of subsequent weekly heroin use during the follow-up period (adjusted odds ratio; 95% confidence interval [AOR; 95% CI]: 0.24; 0.14-0.40). We also found that MMT was positively associated with adherence (AOR 1.52; 95% CI 1.16-2.00), HIV-1 RNA suppression (AOR 1.34; 95% CI 1.00-1.79), and CD4 cell count rise (AOR 1.58; 95% CI 1.26-1.99). CONCLUSIONS: Among HIV/HCV co-infected IDUs on HAART, enrollment in MMT was associated with reduced heroin use, and improved adherence, HIV-1 RNA suppression and CD4 cell count response. Integrating opiate addiction care and HIV care may provide improved health outcomes for this vulnerable population and should be further explored.

Adult↗
PubMed2006

Impact of HAART and injection drug use on life expectancy of two HIV-positive cohorts in British Columbia.

BACKGROUND: The introduction of HAART has led to consistent improvements in survival among HIV-infected individuals. However, there is evidence that not all populations have benefited equally from HAART and that mortality rates are higher in HIV-infected injection drug users than in non-users. OBJECTIVE: To model life expectancies for HIV-positive individuals subdivided according to history of injection drug use and treatment with HAART. DESIGN: Population-based study of HIV-positive persons in British Columbia's HIV/AIDS treatment program. METHODS: The primary outcome measures in this study were life expectancy at exact age 20 and potential years of life lost. RESULTS: The highest life expectancy (38.9 years) and lowest potential years of life lost were measured for individuals taking HAART and without a history of injection drug use. The lowest life expectancy (19.1 years) and highest potential years of life lost were measured in HIV-positive injection drug users who were not taking HAART. CONCLUSIONS: There are substantial disparities in life expectancy for persons living with HIV in British Columbia. Members of the injection drug community, particularly those who are not taking HAART, experience elevated mortality in comparison with those without a history of drug use.

Adult↗
PubMed2006

Potential community and public health impacts of medically supervised safer smoking facilities for crack cocaine users.

There is growing evidence of the public health and community harms associated with crack cocaine smoking, particularly the risk of blood-borne transmission through non-parenteral routes. In response, community advocates and policy makers in Vancouver, Canada are calling for an exemption from Health Canada to pilot a medically supervised safer smoking facility (SSF) for non-injection drug users (NIDU). Current reluctance on the part of health authorities is likely due to the lack of existing evidence surrounding the extent of related harm and potential uptake of such a facility among NIDUs in this setting. In November 2004, a feasibility study was conducted among 437 crack cocaine smokers. Univariate analyses were conducted to determine associations with willingness to use a SSF and logistic regression was used to adjust for potentially confounding variables (p < 0.05). Variables found to be independently associated with willingness to use a SSF included recent injection drug use (OR = 1.72, 95% CI: 1.09-2.70), having equipment confiscated or broken by police (OR = 1.96, 95% CI: 1.24-2.85), crack bingeing (OR = 2.16, 95% CI: 1.39-3.12), smoking crack in public places (OR = 2.48, 95% CI: 1.65-3.27), borrowing crack pipes (OR = 2.50, 95% CI: 1.86-3.40), and burns/inhaled brillo due to rushing smoke in public places (OR = 4.37, 95% CI: 2.71-8.64). The results suggest a strong potential for a SSF to reduce the health related harms and address concerns of public order and open drug use among crack cocaine smokers should a facility be implemented in this setting.

Journal Article↗
PubMed2006

Hepatitis C virus reinfection in injection drug users.

Spontaneous clearance of hepatitis C (HCV) may provide protection against reinfection. In a large community-based cohort study of 3,553 inner-city residents (mainly injection drug users), we identified HCV-infected individuals in whom virological clearance had occurred and compared the rate of reinfection in this group with that observed in previously uninfected members of the same cohort. We identified 926 HCV-uninfected and 658 HCV-infected viremic subjects at baseline, with 152 of 658 (23.1%) spontaneously clearing viremia over a median follow-up of 5.2 years (IQR, 2.8-7.4). At baseline, individuals with HCV clearance were more likely to be HIV coinfected (P < .001) and to be engaged in frequent illicit drug use (P = .004) and injection drug use (P < .001). The occurrence of HCV infection was lower in individuals with previous infection (14/152, 9.2%) compared with that in those without previous infection (172/926, 18.6%), with incidence rates of 1.8 (95% CI, 0.9-3.0 cases/100 person-years) and 8.1 (95% CI, 6.9-9.4 cases/100 person-years) cases/100 person-years, respectively, after accounting for follow-up. In a logistic regression analysis, with previous HCV infection assessed as a covariate with other potential confounding variables (age, sex, ethnicity, HIV infection, housing status, and illicit and injection drug use), individuals with previous HCV infection and viral clearance were 4 times less likely to develop infection than those infected for the first time (adjusted odds ratio, 0.23; 95% CI, 0.10-0.51, P < .001). In conclusion, individuals with clearance of HCV infection may have a lower risk of acquiring HCV than individuals who have never been infected, despite ongoing exposure to HCV.

Adult↗
PubMed2006

Factors associated with buying and selling syringes among injection drug users in a setting of one of North America's largest syringe exchange programs.

We performed analyses of syringe buying and syringe selling among Vancouver injection drug users, recruited from May 1996 and followed up between November 2002 and August 2003, in the context of one of North America's largest syringe exchange programs (SEPs). An interviewer-administered questionnaire, approximately 45 minutes in duration, was used to collect information regarding risk factors for HIV infection and sources of sterile syringes. Seventy participants (15%) reported syringe selling and 122 (26%) reported syringe buying. Syringe sellers were more likely to be female, reside in unstable housing, need help injecting, and have visited the SEP at least once weekly. Syringe buyers were more likely to need help injecting, have difficulty finding new syringes, have binged on drugs, and have visited the SEP at least once weekly. Syringe buying most frequently occurred when the SEP was closed.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Attendance, drug use patterns, and referrals made from North America's first supervised injection facility.

BACKGROUND: North America's first government sanctioned supervised injection facility (SIF) was opened in Vancouver in response to the serious health and social consequences of injection drug use and the perseverance of committed advocates and drug user groups who demanded change. This analysis was conducted to describe the attendance, demographic characteristics, drug use patterns, and referrals made during the first 18 months of operation. METHODS: As part of the evaluation strategy for the SIF, information is collected through a comprehensive on-site database designed to track attendance and the daily activities within the facility. All users of the SIF must sign a waiver form and are then entered into a database using a unique identifier of their choice. This identifier is used at each subsequent visit to provide a prospective record of attendance, drug use, and interventions. RESULTS: From 10 March 2004 to 30 April 2005 inclusive, there were 4764 unique individuals who registered at the SIF. The facility successfully attracted a range of community injection drug users including women (23%) and members of the Aboriginal community (18%). Although heroin was used in 46% of all injections, cocaine was injected 37% of the time. There were 273 witnessed overdoses with no fatalities. During just 12 months of observation, 2171 individual referrals were made with the majority (37%) being referred for addiction counseling. INTERPRETATION: Vancouver's SIF has successfully been integrated into the community, has attracted a wide cross section of community injection drug users, has intervened in overdoses, and initiated over 2000 referrals to counseling and other support services. These findings should be useful for other settings considering SIF trials.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Slower uptake of HIV antiretroviral therapy among Aboriginal injection drug users.

OBJECTIVES: We examined the time to antiretroviral therapy (ART) use among antiretroviral naïve HIV infected injection drug users participating in a prospective cohort study in Vancouver, Canada. METHODS: Time to the initiation of ART was evaluated using Kaplan-Meier methods and Cox proportional hazards regression. The cohort was stratified based on Aboriginal and non-Aboriginal (primarily Caucasian) ethnicity. RESULTS: Between May 1996 and May 2003, 312 HIV-infected individuals were enrolled into the cohort. At 24 months after enrollment, the rate of ART use was 29.2% among Aboriginal participants and was 53.7% among non-Aboriginal participants (log-rank P=0.023), and lower uptake of ART persisted in multivariate analyses (relative hazard = 0.37 [95% CI: 0.15-0.93]; P = 0.035). CONCLUSIONS: These findings demonstrate lower uptake of HIV/AIDS care among Aboriginal injection drug users and demonstrate the need for interventions to improve access to HIV care among indigenous populations.

Anti-Retroviral Agents↗
PubMed2005

Requiring help injecting independently predicts incident HIV infection among injection drug users.

BACKGROUND: Requiring help injecting has been associated with syringe sharing among injection drug users (IDUs). No prospective study has fully examined this risk factor and its relation to rates of HIV infection. We investigated whether requiring help injecting illicit drugs was a predictor of HIV infection among a prospective cohort of IDUs. METHODS: The Vancouver Injection Drug User Study is a prospective study of more than 1500 IDUs who have been recruited from the Downtown Eastside of Vancouver since May 1996. At baseline and semiannually, subjects provided blood samples and completed an interviewer-administered questionnaire. The questionnaire elicits demographic data as well as information about drug use, HIV risk behavior, and drug treatment. HIV incidence rates were calculated using Kaplan-Meier methods, and Cox regression determined independent predictors of seroconversion. RESULTS: A total of 1013 baseline HIV-negative participants were eligible for this study. Within this population, 418 (41.3%) participants had required help injecting during the last 6 months at baseline. Participants requiring help injecting were more likely to be female (odds ratio = 2.3, 95% confidence interval [CI]: 1.8-3.0; P < 0.001), were slightly younger (33.5 vs. 34.9 years of age; P = 0.014), and had fewer years of experience injecting drugs (7 vs. 11 years; P < or = 0.001). Among participants who required help injecting at baseline, cumulative HIV incidence at 36 months was 16.1% compared with 8.8% among participants who did not require help injecting (log-rank, P < 0.001). In an adjusted model controlling for potential confounding variables, being aboriginal (relative hazard [RH] = 1.68, 95% CI: 1.15-2.48), injecting cocaine daily (RH = 2.71, 95% CI: 1.87-3.95), and requiring help injecting (RH = 1.79, 95% CI: 1.23-2.62) remained independent predictors of HIV seroconversion. CONCLUSIONS: These data demonstrate the need for interventions to reduce the risk of HIV infection among IDUs who require help injecting.

Adult↗
PubMed2005

Access and utilization of HIV treatment and services among women sex workers in Vancouver's Downtown Eastside.

Many HIV-infected women are not realizing the benefits of highly active antiretroviral therapy (HAART) despite significant advancements in treatment. Women in Vancouver's Downtown Eastside (DTES) are highly marginalized and struggle with multiple morbidities, unstable housing, addiction, survival sex, and elevated risk of sexual and drug-related harms, including HIV infection. Although recent studies have identified the heightened risk of HIV infection among women engaged in sex work and injection drug use, the uptake of HIV care among this population has received little attention. The objectives of this study are to evaluate the needs of women engaged in survival sex work and to assess utilization and acceptance of HAART. During November 2003, a baseline needs assessment was conducted among 159 women through a low-threshold drop-in centre servicing street-level sex workers in Vancouver. Cross-sectional data were used to describe the sociodemographic characteristics, drug use patterns, HIV/hepatitis C virus (HCV) testing and status, and attitudes towards HAART. High rates of cocaine injection, heroin injection, and smokeable crack cocaine use reflect the vulnerable and chaotic nature of this population. Although preliminary findings suggest an overall high uptake of health and social services, there was limited attention to HIV care with only 9% of the women on HAART. Self-reported barriers to accessing treatment were largely attributed to misinformation and misconceptions about treatment. Given the acceptability of accessing HAART through community interventions and women specific services, this study highlights the potential to reach this highly marginalized group and provides valuable baseline information on a population that has remained largely outside consistent HIV care.

Adult↗
PubMed2005

A description of a peer-run supervised injection site for injection drug users.

Owing to the ongoing health crisis among injection drug users in Vancouver, Canada, there have been repeated calls for the establishment of supervised injection sites (SIS) since the early 1990s. In April 2003, a group of advocates and drug users opened an unsanctioned SIS in Vancouver's Downtown Eastside. The "327 SIS" operated for 184 days. During the operation of the SIS, volunteers supervised over 3,000 injections by a high-risk injection drug using population. The SIS provided a sterile environment for injection drug use without measured negative consequences and demonstrated the feasibility of a peer-driven low-threshold SIS.

Adult↗
PubMed2005

Potential uptake and correlates of willingness to use a supervised smoking facility for noninjection illicit drug use.

Many cities are experiencing infectious disease epidemics and substantial community harms as a result of illicit drug use. Although medically supervised smoking facilities (SSFs) remain untested in North America, local health officials in Vancouver are considering to prepare a submission to Health Canada for an exemption to open Canada's first SSF for evaluation. Reluctance of health policymakers to initiate a pilot study of SSFs may be due in part to outstanding questions regarding the potential uptake and community impacts of the intervention. This study was conducted to evaluate the prevalence and correlates of willingness to use an SSF among illicit drug smokers who are enrolled in the Vancouver Injection Drug Users Study. Participants who reported actively smoking cocaine, heroin, or methamphetamine who returned for follow-up between June 2002 and December 2002 were eligible for these analyses. Those who reported willingness to use an SSF were compared with those who were unwilling to use an SSF by using logistic regression analyses. Four hundred and forty-three participants were eligible for this study. Among respondents, 124 (27.99%) expressed willingness to attend an SSF. Variables that were independently associated with willingness to attend an SSF in multivariate analyses included sex-trade work (adjusted odds ratio [AOR]=1.85), crack pipe sharing (AOR=2.24), and residing in the city's HIV epicentre (AOR =1.64). We found that participants who demonstrated a willingness to attend an SSF were more likely to be involved in the sex trade and share crack pipes. Although the impact of SSFs in North America can only be quantified by scientific evaluation, these data indicate a potential for public health and community benefits if SSFs were to become available.

Adult↗