Search PubMed⌕ Search

Biomedical subjects

Mark W Tyndall

Publications and source records attributed to Mark W Tyndall.

At least 37 records · Page 2Linked to original sources
PubMed2005

Do supervised injecting facilities attract higher-risk injection drug users?

BACKGROUND: In Western Europe and elsewhere, medically supervised safer injection facilities (SIFs) are increasingly being implemented for the prevention of health- and community-related harms among injection drug users (IDUs), although few evaluations have been conducted, and there have been questions regarding SIFs' ability to attract high-risk IDUs. We examined whether North America's first SIF was attracting IDUs who were at greatest risk of overdose and blood-borne disease infection. METHODS: We examined data from a community-recruited cohort study of IDUs. The prevalence of SIF use was determined based on questionnaire data obtained after the SIF's opening, and we determined predictors of initiating future SIF use based on behavioral information obtained from questionnaire data obtained before the SIF's opening. Pearson's chi-square test was used to compare characteristics of IDUs who did and did not subsequently initiate SIF use. RESULTS: Overall, 400 active injection drug users returned for follow-up between December 1, 2003 and May 1, 2004, among whom 178 (45%) reported ever using the SIF. When we examined behavioral data collected before the SIF's opening, those who initiated SIF use were more likely to be aged <30 years (odds ratio [OR]=1.6, 95% confidence interval [CI]=1.0-2.7], p=0.04); public injection drug users (OR=2.6, 95% CI=1.7-3.9, p<0.001); homeless or residing in unstable housing (OR=1.7, 95% CI=1.2-2.7, p=0.008); daily heroin users (OR=2.1, 95% CI=1.3-3.2, p=0.001); daily cocaine users (OR=1.6, 95% CI=1.1-2.5, p=0.025); and those who had recently had a nonfatal overdose (OR=2.7, 95% CI=1.2-6.1, p=0.016). CONCLUSIONS: This study indicated that the SIF attracted IDUs who have been shown to be at elevated risk of blood-borne disease infection and overdose, and IDUs who were contributing to the public drug use problem and unsafe syringe disposal problems stemming from public injection drug use.

Adult↗
PubMed2005

Patterns of opioid and cocaine co-use: a descriptive study in a Canadian sample of untreated opioid-dependent individuals.

This study examined prevalence and patterns of co-use of opioids and cocaine in regular users of illicit opioids (N = 729) recruited from 5 Canadian cities. Fifty-seven percent (n = 417) reported having used both opioids and cocaine in the month and week preceding the interview; of these, 73% (n = 304) were able to identify a typical pattern of daily co-use. In a typical day, injectors of opioids and cocaine (n = 119) and injectors of opioids who inhaled cocaine (n = 111) showed stable opioid use but variable cocaine use, which peaked at 21 hr. Overall, 30% of the individuals used both drugs exclusively in a sequential fashion, 35% reported taking opioids and cocaine within the same hour, and 35% reported taking them together at the same time or mixing them. These findings indicate that different individuals display different patterns of opioids and cocaine co-use.

Adolescent↗
PubMed2005

Nonadherence to antiretroviral therapy among a community with endemic rates of injection drug use.

Highly active antiretroviral therapy (HAART) has resulted in major reductions in HIV-related morbidity and mortality. However, long-term use of HAART is challenging, and substantial numbers of patients discontinue their medications prematurely. The purpose of this analysis is to describe HAART adherence rates among a large urban cohort and examine factors associated with adherence (based on refill compliance). Of the 184 eligible participants, 129 (70%) were less than 95% adherent. Variables independently associated with nonadherence included frequent heroin injection (adjusted odds ratio [AOR] = 2.6, 95% confidence interval [CI], 1.6-4.0), baseline CD4 count less than 200 cells/mm(3) (AOR = 2.5; 95% CI, 1.9-3.2), and poor treatment by health care professionals (AOR = 1.7; 95% CI, 1.2-3.0). Variables inversely associated with HAART nonadherence included attaining viral load suppression (AOR = 0.3; 95% CI, 0.2-0.5) and methadone maintenance therapy (AOR = 0.5; 95% CI, 0.4-0.9). Innovative strategies that address the social barriers facing marginalized populations are needed to support the long-term continuation of HAART.

Antiretroviral Therapy, Highly Active↗
PubMed2004

Methodology for evaluating Insite: Canada's first medically supervised safer injection facility for injection drug users.

Many Canadian cities are experiencing ongoing infectious disease and overdose epidemics among injection drug users (IDUs). In particular, Human Immunodeficiency Virus (HIV) and hepatitis C Virus (HCV) have become endemic in many settings and bacterial and viral infections, such as endocarditis and cellulitis, have become extremely common among this population. In an effort to reduce these public health concerns and the public order problems associated with public injection drug use, in September 2003, Vancouver, Canada opened a pilot medically supervised safer injecting facility (SIF), where IDUs can inject pre-obtained illicit drugs under the supervision of medical staff. The SIF was granted a legal exemption to operate on the condition that its impacts be rigorously evaluated. In order to ensure that the evaluation is appropriately open to scrutiny among the public health community, the present article was prepared to outline the methodology for evaluating the SIF and report on some preliminary observations. The evaluation is primarily structured around a prospective cohort of SIF users, that will examine risk behavior, blood-borne infection transmission, overdose, and health service use. These analyses will be augmented with process data from within the SIF, as well as survey's of local residents and qualitative interviews with users, staff, and key stakeholders, and standardised evaluations of public order changes. Preliminary observations suggest that the site has been successful in attracting IDUs into its programs and in turn helped to reduce public drug use. However, each of the indicators described above is the subject of a rigorous scientific evaluation that is attempting to quantify the overall impacts of the site and identify both benefits and potentially harmful consequences and it will take several years before the SIF's impacts can be appropriately examined.

Journal Article↗
PubMed2004

Changes in public order after the opening of a medically supervised safer injecting facility for illicit injection drug users.

BACKGROUND: North America's first medically supervised safer injecting facility for illicit injection drug users was opened in Vancouver on Sept. 22, 2003. Although similar facilities exist in a number of European cities and in Sydney, Australia, no standardized evaluations of their impact have been presented in the scientific literature. METHODS: Using a standardized prospective data collection protocol, we measured injection-related public order problems during the 6 weeks before and the 12 weeks after the opening of the safer injecting facility in Vancouver. We measured changes in the number of drug users injecting in public, publicly discarded syringes and injection-related litter. We used Poisson log-linear regression models to evaluate changes in these public order indicators while considering potential confounding variables such as police presence and rainfall. RESULTS: In stratified linear regression models, the 12-week period after the facility's opening was independently associated with reductions in the number of drug users injecting in public (p < 0.001), publicly discarded syringes (p < 0.001) and injection-related litter (p < 0.001). The predicted mean daily number of drug users injecting in public was 4.3 (95% confidence interval [CI] 3.5-5.4) during the period before the facility's opening and 2.4 (95% CI 1.9-3.0) after the opening; the corresponding predicted mean daily numbers of publicly discarded syringes were 11.5 (95% CI 10.0-13.2) and 5.4 (95% CI 4.7-6.2). Externally compiled statistics from the city of Vancouver on the number of syringes discarded in outdoor safe disposal boxes were consistent with our findings. INTERPRETATION: The opening of the safer injecting facility was independently associated with improvements in several measures of public order, including reduced public injection drug use and public syringe disposal.

British Columbia↗
PubMed2004

Displacement of Canada's largest public illicit drug market in response to a police crackdown.

BACKGROUND: Law enforcement is often used in an effort to reduce the social, community and health-related harms of illicit drug use by injection drug users (IDUs). There are, however, few data on the benefits of such enforcement or on the potential harms. A large-scale police "crackdown" to control illicit drug use in Vancouver's Downtown Eastside provided us with an opportunity to evaluate the effect. METHODS: As part of our ongoing prospective cohort study of IDUs in Vancouver, we examined data collected from 244 IDUs in the 3 months before the police crackdown and from 142 IDUs in the 3 months after the start of the crackdown, on Apr. 7, 2003. All study subjects were active drug users. We also examined external data on needle exchanges and syringe disposal. RESULTS: The 2 groups of IDUs were statistically similar: they were mainly young (mean age 39 years) and male (63%), and they had injected illicit drugs for 13 years on average. Ethnic background and the proportion homeless were also similar. There were no statistically significant reported differences (all p > 0.1) in the street price of heroin, cocaine or "crack" in the 2 periods. In the 3-month periods before and after the crackdown, respectively, the rates of daily heroin injection were 27.9% and 26.8%, daily cocaine injection 28.7% and 27.5%, and daily crack use 59.4% and 60.6% (all p > 0.1). The proportions of study subjects receiving methadone treatment, 41.0% and 44.4% (p = 0.516), did not differ. However, the proportions reporting a change in where drugs were used, 22.5% and 33.8% (p < 0.05), and the proportions reporting a change in the neighbourhood of use because of police presence, 18.1% and 26.8% (p < 0.05), increased significantly. Needle-exchange data confirmed that the community levels of drug use were unchanged. Disposal statistics demonstrated that the monthly average number of used syringes found on the streets outside the traditional area of drug use increased from 784 in the 3 months before Apr. 1 to 1253 in the subsequent 3 months (p = 0.002) and the monthly average number of used syringes found in public boxes for the safe disposal of syringes decreased from 865 to 502 (p = 0.018). INTERPRETATION: The effort to control illicit drug use did not alter the price of drugs or the frequency of use, nor did it encourage enrollment in methadone treatment programs. Several measures indicated displacement of injection drug use from the area of the crackdown into adjacent areas of the city, which has implications for both recruitment of new initiates into injection drug use and HIV prevention efforts.

Adult↗
PubMed2004

Rationale for evaluating North America's first medically supervised safer-injecting facility.

Many cities throughout the world are experiencing ongoing infectious disease and overdose epidemics among illicit injection drug users (IDUs). In particular, HIV and hepatitis C virus (HCV) have become endemic in many settings and bacterial infections, such as endocarditis, have become extremely common among this population. In an effort to reduce these public health concerns, in September 2003, Vancouver, Canada, opened a pilot medically supervised safer- injecting facility (SIF), where IDUs can inject pre-obtained illicit drugs under the supervision of medical staff. Before and since the facility's opening, there has been a substantial misunderstanding about the rationale for evaluating SIF as a public-health strategy. This article outlines the evidence and rationale in support of the Canadian initiative. This rationale involves limitations in conventionally applied drug-control efforts, and gaps in current public-health policies in controlling the spread of infectious diseases, and the incidence of overdose among IDUs.

British Columbia↗
PubMed2004

Intensity of drug injection as a determinant of sustained injection cessation among chronic drug users: the interface with social factors and service utilization.

AIMS: The objective of this study was to identify factors associated with sustained injection cessation and to examine further the relationship between the occurrence of sustained injection cessation of injection drug users (IDUs) and prior injection frequency. DESIGN AND SETTING: IDUs in the Montreal St Luc Cohort who had at least three consecutive interviews between 1995 and 1999 were included. Sustained injection cessation was defined as a period of at least 7 consecutive months without injection. All IDUs completed interview-administered questionnaires on socio-demographic characteristics, drug and sexual behaviours and health-related issues. Logistic regression was used for analyses. FINDINGS: A total of 186/1004 (18.5%) IDUs reported a period of sustained injection cessation during the study period. In multivariate analysis, HIV-positive status, 'booting' and cumulative time spent in prison were negatively associated with injection cessation, while injection initiation after 35 years of age and frequent crack use were positively associated with injection cessation. We found a negative association between the occurrence of injection cessation and the frequency of injection; the odds ratios (OR) for cessation were 0.49 [95% confidence interval (CI): 0.03, 0.78] for IDUs who injected 30-100 times and 0.21 (95% CI: 0.10, 0.46) for IDUs who injected more than 100 times in the previous month. Attending needle exchange programmes (NEPs) or pharmacies appeared to be a modifier of the relation between cessation and prior injection frequency. The OR was 0.68 (95% CI: 0.42, 1.12) for IDUs who injected 30-100 times prior to injection and attended NEPs or pharmacies and was 0.07 (0.01, 0.30) for IDUs who did not use these services. CONCLUSIONS: Overall, a fifth of IDUs experienced at least one episode of injection cessation of 7 months or more during a period of 4.5 years. Our data suggest that NEPs and pharmacies may have played a role in inducing injection cessation episodes in a subgroup of IDUs. Research is needed to better identify the characteristics of IDUs who could benefit from an injection cessation intervention strategy. This information is important for social and health policy planning.

Adolescent↗
PubMed2004

Adherence to antiretroviral therapy and CD4 T-cell count responses among HIV-infected injection drug users.

OBJECTIVE: To evaluate the time to CD4 cell count response (> or = 50 cells/mm3) among patients initiating highly active antiretroviral therapy (HAART) with and without a history of injection drug use, and to examine the potential role of non-adherence to HAART on differential CD4 responses. METHODS: Population-based analysis of treatment-naive patients initiating HAART during the period 1 August 1996 to 31 July 2000 and who were followed until 31 March 2002. Patients were stratified based on 95% adherence and history of injection drug use, and Kaplan-Meier methods and Cox regression were used to evaluate CD4 response rates and factors associated with CD4 responses. RESULTS: Overall, the CD4 cell count response rate was slower among injection drug users in Kaplan-Meier analyses (log-rank: P<0.05). However, no differences existed when the analyses were restricted to adherent patients (log-rank: P=0.349). Similarly, the differences in the time to CD4 cell count response observed in univariate Cox regression analyses for patients with a history of injection drug use [relative hazard: 0.85 (95% CI: 0.75-0.97)] diminished after adjustment for adherence [adjusted relative hazard: 1.02 (95% CI: 0.89-1.16)]. CONCLUSION: These data demonstrate the importance of adherence on CD4 cell count responses and highlight the need for interventions to improve antiretroviral adherence among injection drug user.

Adult↗
PubMed2004

Initiating highly active antiretroviral therapy and continuity of HIV care: the impact of incarceration and prison release on adherence and HIV treatment outcomes.

OBJECTIVE: To examine the effect of incarceration within 12 months of initiating highly active antiretroviral therapy (HAART) on non-adherence and HIV-1 RNA suppression. METHODS: We compared the adherence and virological outcomes among participants in a population-based HIV/AIDS Drug Treatment Program in British Columbia, Canada, by history of incarceration in a provincial prison. Participants who were HIV-infected, naive to HAART and who were prescribed treatment between 1 July 1997 and 1 March 2002 were eligible for this study. Logistic regression was used to determine the factors associated with non-adherence and Cox proportional hazards modelling was used to determine the factors associated with HIV-1 RNA suppression adjusting for age, gender, history of drug use, baseline HIV-1 RNA, baseline CD4 cell count, type of antiretroviral regimen [two nucleosides + protease inhibitor (PI) vs two nucleosides + non-nucleoside reverse transcriptase inhibitor (NNRTI)], physician's HIV-related experience for each subject and adherence as measured by pharmacy refill compliance. RESULTS: There were 1746 subjects (101 incarcerated/1645 non-incarcerated) who started antiretroviral therapy between 1 July 1997 and 1 March 2002. Of those incarcerated, 50 initiated HAART while in prison and 27 subjects were released but returned to prison in the follow-up period. Subjects received antiretroviral therapy while incarcerated for a median number of 4 months [interquartile range (IQR): 2-10]. Multiple logistic regression results showed that a history of incarceration within 12 months of initiating HAART independently increased the odds of non-adherence [adjusted odds ratio (AOR): 2.40; 95% confidence interval (95% CI): 1.54-3.75]. A history of injected drug use was also associated with non-adherence (AOR: 1.49; 95% CI: 1.17-1.90). The following factors were negatively associated with non-adherence: older age (AOR: 0.81; 95% CI: 0.72-0.91), male sex (AOR: 0.50; 95% CI: 0.38-0.65) and higher physician HIV-related experience (AOR: 0.97; 95% CI: 0.96-0.98). In addition, a history of incarceration within 12 months of initiating HAART reduced the odds of achieving HIV-1 RNA suppression [adjusted hazards ratio (AHR): 0.68; 95% CI: 0.51-0.89]. Other factors negatively associated with viral suppression included a history of drug injection (AHR: 0.79; 95% CI: 0.69-0.91), two nucleosides + PI vs two nucleosides + NNRTI (AHR: 0.77; 95% CI: 0.69-0.87), higher baseline HIV-1 RNA (AHR: 0.66; 95% CI: 0.62-0.70). Higher adherence was positively associated with viral suppression (AHR: 1.38; 95% CI: 1.34-1.42). Among the 101 subjects who were incarcerated in the first year of starting HAART, the time spent in jail was positively associated with HIV-1 RNA suppression (HR: 1.06; 95% CI: 1.02-1.10). CONCLUSION: HIV-infected subjects with a history of incarceration within 12 months of initiating HAART have higher odds of non-adherence and, consequently, lower probability of achieving HIV-1 RNA suppression. The longer their sentence, however, the higher the probability of virological suppression. The British Columbian provincial prison system provided a structured setting for HAART but subjects are unable to continue this level of adherence upon release. Strategies to ensure continuation of HIV/AIDS care for HIV-infected individuals leaving the criminal justice system must be a public health priority.

Adult↗
PubMed2003

Potential use of safer injecting facilities among injection drug users in Vancouver's Downtown Eastside.

BACKGROUND: The Vancouver Coastal Health Authority will initiate North America's first sanctioned safer injecting facility, as a pilot project, on Sept. 15, 2003. The analyses presented here were conducted to estimate the potential use of safer injecting facilities by local illicit injection drug users (IDUs) and to evaluate the potential impact of newly established Health Canada restrictions and current police activities on the use of the proposed facility. METHODS: During April and May 2003, we recruited active IDUs in Vancouver's Downtown Eastside to participate in a feasibility study. We used descriptive and univariate statistics to determine potential use of a safer injecting facility and to explore factors associated with willingness to use such a facility with and without federal restrictions and police presence. RESULTS: Overall, 458 street-recruited IDUs completed an interviewer-administered survey, of whom 422 (92%) reported a willingness to use a safer injecting facility. Those expressing willingness were more likely to inject in public (odds ratio [OR] 3.9, 95% confidence interval [CI] 1.9-8.0). When the restrictions in the Health Canada guidelines were considered, only 144 (31%) participants were willing to use a safer injecting facility. IDUs who inject alone were more likely (OR 1.8, 95% CI 1.0-3.1) and women were less likely (OR 0.6, 95% CI 0.4-0.9) to be willing to use a safer injecting facility operating under these restrictions. Only 103 (22%) of the participants said they would be willing to use a safer injecting facility if police were stationed near the entrance. INTERPRETATION: Most IDUs participating in this study expressed a willingness to use a safer injecting facility. However, willingness declined substantially when the IDUs were asked about using a facility operating under selected Health Canada restrictions and in the event that police were stationed near the entrance.

Adult↗
PubMed2003

Prevalence and correlates of untreated human immunodeficiency virus type 1 infection among persons who have died in the era of modern antiretroviral therapy.

We evaluated all human immunodeficiency virus (HIV)-related deaths over the period 1 January 1995-31 December 2001 in a Canadian province in which all HIV care and antiretroviral therapy are provided free of charge. Persons who had received antiretroviral drugs before death were compared with those who had died without ever receiving HIV treatment, by fitting a logistic model. Overall, 1239 deaths were attributed to HIV infection during the study period. Of these, 406 (32.8%) occurred among persons who had never received any HIV treatment. In adjusted analyses, aboriginal ethnicity, female sex, and lower median income were negatively associated with receiving HIV treatment before death. Furthermore, among the 833 individuals who received treatment before death, only 379 (45.5%) received antiretroviral medication >or=75% of the time during their first year receiving therapy. The data demonstrate the need for novel interventions to expand HIV care to specific populations.

Anti-HIV Agents↗
PubMed2003

Adherence and plasma HIV RNA responses to highly active antiretroviral therapy among HIV-1 infected injection drug users.

BACKGROUND: The benefits of highly active antiretroviral therapy (HAART) for the treatment of HIV infection are well documented, but concerns regarding access and adherence to HAART are growing. We evaluated virological responses to HAART among HIV-1 infected patients who were injection drug users (IDUs) in a population-based setting where HIV/AIDS care is delivered free of charge. METHODS: We evaluated previously untreated HIV-1 infected men and women who initiated HAART between Aug. 1, 1996, and July 31, 2000, and who were followed until Mar. 31, 2002, in a province-wide HIV treatment program. We used Kaplan-Meier methods and Cox proportional hazards regression in our evaluation of time to suppression (i.e., less than 500 copies/mL) and rebound (i.e., 500 copies/mL or more) of plasma HIV-1 RNA, with patients stratified according to whether or not they had a history of injection drug use. RESULTS: Overall, 1422 patients initiated HAART during the study period, of whom 359 (25.2%) were IDUs. In Kaplan-Meier analyses, the cumulative suppression rate at 12 months after initiation of HAART was 70.8% for non-IDUs and 51.4% for IDUs (p < 0.001) (these values include people who achieved suppression before 12 months but who might not have been followed for the full 12-month period). Among patients who achieved suppression of plasma HIV-1 RNA, the cumulative rebound rate at 12 months after initial suppression was 23.8% for non-IDUs and 34.7% for IDUs (p < 0.001). However, after adjustment for adherence and other covariates, the rates of HIV-1 RNA suppression (adjusted relative hazard 0.9, 95% confidence interval [CI] 0.7-1.0) and HIV-1 RNA rebound (adjusted relative hazard 1.3, 95% CI 1.0-1.6) were similar between non-IDUs and IDUs. Differences between non-IDUs and IDUs were even less pronounced in subanalyses that considered only therapy-adherent patients (p > 0.1). INTERPRETATION: Non-IDUs and IDUs had similar rates of HIV-1 RNA suppression and rebound after the initiation of HAART, once lower levels of adherence were taken into account. Nevertheless, the lower virological response rates among IDUs suggest that, unless interventions are undertaken to improve adherence, these patients may experience elevated rates of disease progression and use of medical services in our setting.

Adult↗
PubMed2003

Intensive injection cocaine use as the primary risk factor in the Vancouver HIV-1 epidemic.

OBJECTIVES: The explosive and ongoing injecting drug use-related HIV-1 epidemic in Vancouver continues to receive international attention. This study was conducted to determine how patterns of cocaine use influence the risk of HIV infection. METHODS: The Vancouver Injection Drug Users Study is an open prospective cohort of injecting drug users that began in May 1996. At enrollment and at semi-annual follow-up visits an interviewer administers a detailed semi-structured questionnaire. Cox proportional hazards models were used to determine behavioral and drug use patterns reported in the 6 months prior to HIV seroconversion. RESULTS: One-hundred and nine incident HIV infections have been observed during a mean follow-up of 31 months, from 940 HIV-seronegative participants. During the 6 months prior to seroconversion, predictors of HIV infection were injecting cocaine use [adjusted hazards ratio (AHR), 3.72], incarceration (AHR, 2.74), unstable housing (AHR, 2.36), methadone maintenance treatment (AHR, 1.98), and Aboriginal ethnicity (AHR, 1.78). Injecting cocaine use was predictive of HIV infection in a dose-dependent fashion. Compared with infrequent cocaine users, participants who averaged more than three injections per day were seven times more likely to contract HIV. In addition, the time to HIV infection was accelerated among regular cocaine injectors independent of concurrent heroin use. CONCLUSIONS: Injecting cocaine use was a strong, dose-dependent predictor of HIV seroconversion in this poly-drug using population. Injection cocaine users remain particularly vulnerable to HIV infection and treatment options for cocaine dependency remain woefully inadequate.

Adult↗
PubMed2003

Impact of supply-side policies for control of illicit drugs in the face of the AIDS and overdose epidemics: investigation of a massive heroin seizure.

BACKGROUND: More than 93% of the nearly $500 million spent annually on Canada's drug strategy goes toward efforts to reduce the illicit drug supply. However, little is known about the effectiveness of this strategy. On Sept. 2, 2000, Canadian police seized approximately 100 kg of heroin in one of the nation's largest-ever seizures of this drug. An ongoing prospective cohort study of injection drug users afforded an opportunity to evaluate the impact of this seizure. METHODS: The Vancouver Injection Drug User Study is a prospective cohort study of injection drug users that began in 1996. The present study relied primarily on data acquired from participants who were seen during the 30-day periods immediately before and after the seizure. We compared drug use and behavioural characteristics, heroin and cocaine prices, and participants' reports of whether law enforcement had affected their source of drugs or the types of drugs available on the street, as well as overdoses, in these 2 periods. RESULTS: The 138 participants seen before the seizure were similar to the 123 participants seen after the seizure with respect to age, sex, ethnic background, education, HIV serostatus, neighbourhood residence, instability of housing, employment status, use of methadone maintenance therapy and all other measured potential confounders (all p > 0.10). We found no difference in the extent to which participants in the 2 groups reported daily use of heroin, frequency of nonfatal overdoses, or whether law enforcement had affected their source of drugs or the types of drugs available on the street (all p > 0.10). Although we detected no difference in the price of cocaine, the median reported price of heroin went down after the seizure (p = 0.034), which suggests that other shipments compensated for the seizure. External evaluations of deaths from overdoses and heroin purity indicated that the seizure had no impact, nor was any impact seen when the periods of analysis were extended. INTERPRETATION: The massive heroin seizure appeared to have no measurable public health benefit. Closer scrutiny of enforcement efforts is warranted to ensure that resources are delivered to the most efficient and cost-effective public health programs.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Risk factors for elevated HIV incidence among Aboriginal injection drug users in Vancouver.

BACKGROUND: Because of established links between entrenched poverty and risk of HIV infection, there have long been warnings that HIV/AIDS will disproportionately affect Aboriginal people in Canada. We compared HIV incidence rates among Aboriginal and non-Aboriginal injection drug users (IDUs) in Vancouver and studied factors associated with HIV seroconversion among Aboriginal participants. METHODS: This analysis was based on 941 participants (230 Aboriginal people) recruited between May 1996 and December 2000 who were seronegative at enrollment and had completed at least one follow-up visit. Incidence rates were calculated using the Kaplan-Meier method. The Cox proportional hazards regression model was used to identify independent predictors of time to HIV seroconversion among female and male Aboriginal IDUs. RESULTS: As of May 31, 2001, seroconversion had occurred in 112 (11.9%) of the participants, yielding a cumulative incidence of HIV infection at 42 months of 12.7% (95% confidence interval [CI] 10.3%-15.1%). The cumulative incidence at 42 months was significantly higher among the Aboriginal participants than among the non-Aboriginal participants (21.1% v. 10.7%, p < 0.001). This elevation in risk was present in both female and male Aboriginal IDUs. Among the female Aboriginal IDUs, frequent speedball (combined cocaine and heroin) injection (adjusted relative risk [RR] 3.1; 95% CI 1.4-7.1) and going on binges of injection drug use (adjusted RR 2.3; 95% CI 1.0-5.2) were found to be independent predictors of HIV seroconversion. Among the male Aboriginal IDUs, the independent predictors of seroconversion were frequent speedball injection (adjusted RR 2.9; 95% CI 1.0-8.5) and frequent cocaine injection (adjusted RR 2.5; 95% CI 1.0-6.5). INTERPRETATION: In Vancouver, Aboriginal IDUs are becoming HIV positive at twice the rate of non-Aboriginal IDUs. Our findings emphasize the urgent need for an appropriate and effective public health strategy--planned and implemented in partnership with Aboriginal AIDS service organizations and the Aboriginal community--to reduce the harms of injection drug use in this population.

Adolescent↗