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Biomedical subjects

Evan Wood

Publications and source records attributed to Evan Wood.

At least 55 records · Page 3Linked to original sources
PubMed2005

Prevalence and correlates of abscesses among a cohort of injection drug users.

Recent studies have indicated that injection-related infections such as abscesses and cellulitis account for the majority of emergency room visits and acute hospitalizations accrued by local injection drug users. The objective of this analysis was to examine the prevalence and correlates of developing an abscess among a cohort of injection drug users in Vancouver and to identify socio-demographic and drug use variables associated with abscesses at baseline. We examined abscesses among participants enrolled in a prospective cohort of injection drug users. Categorical variables were analyzed using the Pearson's chi-square test and continuous variables were analyzed using the Wilcoxon signed rank test. Among 1 585 baseline participants, 341 (21.5%) reported having an abscess in the last six months. In a logistic regression model that adjusted for all variables that were associated with having an abscess at p < 0.1 in univariate analyses, female gender [odds ratio (OR) = 1.7, [95% CI: 1.2 - 2.4]; p = 0.002), recent incarceration (OR = 1.7, [95% CI: 1.3 - 2.2]; p < 0.001), sex trade involvement (OR = 1.4 [95% CI: 1.0 - 2.0]; p = 0.03), frequent cocaine use (OR = 1.5 [95% CI: 1.2 - 2.0]; p = 0.002) and HIV serostatus (OR = 1.5, [95% CI: 1.2 - 2.0]; p = 0.003) were positively associated with having an abscess. Explanations for these associations require further study, and interventions are needed to address this highly prevalent concern.

Journal Article↗
PubMed2005

Discordant immunologic and virologic responses to highly active antiretroviral therapy are associated with increased mortality and poor adherence to therapy.

OBJECTIVE: To examine the independent association of discordant virologic and immunologic responses to highly active antiretroviral therapy (HAART) with mortality. METHODS: A population-based study of 1527 treatment-naive individuals initiating HAART used Cox proportional hazards modeling to determine the independent association of treatment response at 3 to 9 months with nonaccidental mortality. Logistic regression was used to examine associations with discordant responses. RESULTS: Viral load (VL)/CD4 discordant responses were seen in 235 (15.4%) of subjects, and VL/CD4 responses were seen in 179 (11.7%) of subjects. In adjusted Cox regression models, discordant responses were found to be independently associated with an increased risk of mortality (VL/CD4: relative hazard [RH] = 1.87, 95% confidence interval [CI]: 1.15 to 3.04; VL/CD4: RH = 2.47, 95% CI: 1.54 to 3.95). VL/CD4 discordance was found to be associated with increasing age, baseline HIV RNA load <100,000 copies/mL, baseline CD4 counts <50 cells/muL, the use of lamivudine (3TC)/zidovudine (ZDV), and poor adherence to therapy. VL/CD4 discordance was associated with younger age; injection drug use; baseline HIV RNA load >100,000 copies/mL; the use of 3TC/ZDV, didanosine (ddI)/3TC, or ddI/stavudine; and poor adherence to therapy. CONCLUSION: Discordant responses are independently associated with an increased risk of mortality and are, in turn, associated with poor adherence to therapy.

Adult↗
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

Risk profile of individuals who provide assistance with illicit drug injections.

BACKGROUND: Assisted injection is a common practice among injection drug users (IDU) that carries significant risk for health-related harm. However, little is known about the individuals who provide assistance with injections. METHODS: We evaluated factors associated with providing help injecting among participants enrolled in the Vancouver Injection Drug User Study (VIDUS) using univariate and logistic regression analyses. We also examined self-reported relationships between the provider and the receiver of assisted injection, if compensation was provided for assistance, and what type of compensation was given. RESULTS: Of the 704 IDU eligible for this analysis, 193 (27.4%) had provided help injecting during the last 6 months. Variables independently associated with providing help injecting included: lending one's own syringe (adjusted odds ratio [AOR] = 3.99, p = 0.004); frequent heroin injection (AOR = 3.75, p < 0.001); unstable housing (AOR = 2.15, p < 0.001); binge drug use (AOR = 2.01, p = 0.012); frequent cocaine injection (AOR = 1.95, p = 0.002); and frequent use of crack cocaine (AOR = 1.85, p = 0.002). Help was most often provided to a casual (47.2%) or a close friend (41.5%). Of the 96 (49.7%) individuals who received compensation for providing help, the most common forms of compensation were drugs (89.6%) and money (45.8%). CONCLUSION: Providing help injecting was common among IDU in this cohort and was associated with various high-risk behaviours, including elevated levels of syringe lending. These findings indicate the need for interventions that offset the risks associated with this dangerous practice.

Adult↗
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

Rates of antiretroviral resistance among HIV-infected patients with and without a history of injection drug use.

BACKGROUND: There exist concerns regarding the potential for elevated rates of antiretroviral resistance among HIV-infected injection drug users (IDUs) prescribed highly active antiretroviral therapy (HAART), however, no population-based study has examined if IDUs have elevated rates of antiretroviral resistance in comparison to non-IDUs. OBJECTIVE: To evaluate the time to the development of antiretroviral resistance among antiretroviral-naive patients with and without a history of injection drug use. METHODS: In British Columbia there is a province-wide HIV/AIDS treatment program that provides antiretrovirals free of charge. We examined all antiretroviral-naive patients initiating HAART between 1 August 1996 and 30 September 2000 and who were followed to 31 March 2002. The main outcome measure was the time to class-specific antiretroviral resistance. Cumulative antiretroviral resistance rates among IDUs and non-IDUs were evaluated using Kaplan-Meier methods and relative hazards were estimated using Cox regression. RESULTS: Overall, 1191 antiretroviral-naive patients initiated HAART during the study period. Resistance mutations were observed in 298 (25%) subjects during the first 30 months of HAART. In comparison with non-IDUs, the risk of protease inhibitor resistance [relative hazard (RH), 0.9; 95% confidence interval (CI), 0.5-1.6] and non-nucleoside reverse transcriptase inhibitor resistance (RH, 1.5; 95% CI, 1.0-2.2) were similar among IDUs, and there were no differences in the rates of resistance to the sub-classes of nucleoside reverse transcriptase inhibitors. CONCLUSIONS: Resistance to all major classes of antiretrovirals were similar among IDUs and non-IDUs after 30 months of follow-up. These findings should help to allay fears that prescribing HAART to IDUs may result in elevated rates of resistance.

Adult↗
PubMed2005

Factors associated with methadone maintenance therapy use among a cohort of polysubstance using injection drug users in Vancouver.

We identified methadone maintenance therapy (MMT) use during follow-up interviews and examined associations between MMT use and socio-demographic and drug-related variables using generalized estimating equations (GEE). Of the 1587 participants recruited into this cohort, 170 (11%) were enrolled in MMT at baseline and additional 498 (31%) initiated MMT during follow-up. Of those ever enrolled in MMT, 406 (61%) ceased MMT and re-initiated MMT on more than one occasion. The median treatment duration was 14.4 months. Factors that were negatively and significantly associated with MMT use in multivariate analyses included: Aboriginal ethnicity (adjusted odds ratio [AOR] = 0.40); recent incarceration (AOR = 0.79); sex trade involvement (AOR = 0.87); syringe lending (AOR = 0.72); heroin injection (AOR = 0.64), whereas female gender (AOR = 2.47), HIV positivity (AOR = 1.57), and crack cocaine smoking (AOR = 1.23) were positively and significantly associated with being on MMT. Unstable housing, syringe borrowing, non-fatal overdose, cocaine injection, and residence in Vancouver's Downtown Eastside were not associated with MMT use in multivariate analyses. Our study demonstrates high rates of initiation of and retention in MMT among local IDUs. While the use of MMT was associated with reductions in heroin use and HIV risk behavior, barriers to Aboriginal IDUs were evident, and the association with increased crack cocaine use deserves further study.

Adult↗
PubMed2005

Impact of accessing methadone on the time to initiating HIV treatment among antiretroviral-naive HIV-infected injection drug users.

We examined the impact of methadone maintenance therapy (MMT) on subsequent antiretroviral therapy (ART) use in a prospective cohort of injection drug users. At 24 months after enrollment, the rate of ART use was 69.7% among those who were on MMT at baseline and 44.4% among those not on MMT (log-rank P = 0.001). In a Cox model, the use of MMT was independently associated with an elevated rate of ART use.

Anti-Retroviral Agents↗
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↗
PubMed2005

Why are baseline HIV RNA levels 100,000 copies/mL or greater associated with mortality after the initiation of antiretroviral therapy?

BACKGROUND: There is conflicting evidence regarding the impact of baseline plasma HIV RNA on virologic responses after the initiation of triple-drug antiretroviral therapy (highly active antiretroviral therapy [HAART]). This has made it difficult to interpret the recently reported association between baseline plasma HIV RNA and mortality. We evaluated whether baseline CD4 cell count and plasma HIV RNA predicted virologic suppression (<500 copies/mL) and rebound (> or =500 copies/mL) among adherent HIV-infected patients. METHODS: Antiretroviral-naive HIV-infected patients were stratified by baseline CD4 cell count, plasma HIV RNA, and adherence level. Cox and logistic regression were used to evaluate the time to suppression and rebound and the odds of ever achieving HIV RNA suppression. RESULTS: A total of 1422 individuals initiated HAART between August 1, 1996 and July 31, 2000 and were followed to March 31, 2002. Adherent patients with HIV RNA levels > or =100,000 copies/mL and 50 to 99,999 copies/mL were slower to suppress HIV RNA than patients with baseline HIV RNA <50,000 copies/mL in Kaplan-Meier analyses. Although the odds of RNA suppression among adherent patients with baseline RNA levels <50,000 copies/mL and 50 to 99,999 copies/mL were similar (P = 0.197), patients with baseline HIV RNA > or =100,000 copies/mL were markedly less likely ever to achieve suppression during follow-up (adjusted odds ratio: 0.27 [95% confidence interval: 0.13-0.54]; P < 0.001). No differences in the rate of virologic rebound were observed between adherent patients in the various baseline HIV RNA strata, and CD4 cell count was not associated with suppression or rebound. CONCLUSIONS: Baseline HIV RNA > or =100,000 copies/mL was associated with a significantly lower likelihood of ever achieving HIV RNA suppression during follow-up. These findings likely explain the association between baseline HIV RNA levels and mortality and have important implications for the development of therapeutic guidelines.

Antiretroviral Therapy, Highly Active↗
PubMed2005

Measuring adherence to highly active antiretroviral therapy: implications for research and practice.

Highly active antiretroviral therapy (HAART) has radically changed the course of HIV disease, producing substantial reductions in both HIV-related morbidity and mortality. However, the complexity of the typical daily HAART regimen is substantial, and high levels of adherence are essential for complete and long-term viral suppression and the avoidance of drug resistance. The complexity of HAART has made the assessment of medication adherence of paramount importance. Even though various methods are in use, each measures only a subset of adherence behaviors, and each measure has limited predictive validity. Given the individual and public health concerns associated with adherence to HAART, there is a need for the continued development and validation of measures of medication adherence.

Antiretroviral Therapy, Highly Active↗
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

When to initiate antiretroviral therapy in HIV-1-infected adults: a review for clinicians and patients.

One of the most controversial topics in the medical management of HIV disease is the optimal time to initiate highly active antiretroviral therapy (HAART) in HIV-1-infected adults. Premature exposure to antiretrovirals may precipitate early evolution of resistance and unnecessary side-effects, whereas remaining off HAART until late in the course of HIV disease may lead to reduced therapeutic benefits and elevated mortality. The lack of a randomised clinical trial to consider this issue has resulted in ongoing revision of expert recommendations and substantial variability between international consensus guidelines regarding the optimal time to initiate therapy. Since this uncertainty is a source of unease for both patients and clinicians, we summarise the latest evidence regarding the optimal time to initiate HAART with consideration of the potential benefits and drawbacks of starting HIV treatment at the different levels presently recommended in leading consensus guidelines.

Anti-HIV Agents↗
PubMed2005

Sociodemographic disparities in access to addiction treatment among a cohort of Vancouver injection drug users.

Vancouver's explosive HIV epidemic among injection drug users (IDUs) has received international attention due to the presence of a large needle exchange program. The role of addiction treatment has not been evaluated in this setting. We evaluated factors associated with use of addiction treatment among a prospective cohort of Vancouver IDUs. Addiction treatment was negatively associated with Aboriginal ethnicity and unstable housing, both of which have been associated with HIV infection in previous studies. These findings demonstrate low levels of addiction treatment among Vancouver IDUs and suggest that programs may need to be targeted towards specific populations with poor access.

Adult↗
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↗
PubMed2005

Injection drug use, HIV/AIDS and incarceration: evidence from the Vancouver Injection Drug Users Study.

The reliance on law enforcement as the dominant drug policy approach has resulted in record incarceration rates in many countries. Human rights advocates and public health researchers have argued that the risks of HIV transmission resulting from injection drug use within Canadian prisons must be addressed. Despite a decade of advocacy and some progress made, this remains an urgent public health crisis. In light of these concerns, researchers working with the Vancouver Injection Drug Users Study (VIDUS) have undertaken a series of studies specific to injection drug use and HIV/AIDS in prisons. This article summarizes the body of evidence generated via VIDUS, discusses briefly the related human rights implications, and concludes with recommendations for action.

Antiretroviral Therapy, Highly Active↗