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Biomedical subjects

Evan Wood

Publications and source records attributed to Evan Wood.

At least 91 records · Page 5Linked to original sources
PubMed2004

Harm-reduction activism: a case study of an unsanctioned user-run safe injection site.

Due to the ongoing health crisis among injection drug users in Vancouver, Canada, there have been repeated calls for the establishment of safe injection sites (SISs) since the early 1990s. In April 2003, in response to a large-scale police crackdown and government inaction, a group of activists opened an unsanctioned SIS in Vancouver's Downtown Eastside (DTES). The 327 Carrall Street SIS operated for 181 days despite considerable police harassment and limited financial support. During the operation of the SIS, volunteers supervised over 3000 injections and demonstrated the feasibility of a user-run low-threshold SIS. The experience of the SIS provides valuable lessons for those seeking to advance the interests of injection drug users through community mobilization and direct action approaches. In this article, Thomas Kerr, Megan Oleson, and Evan Wood describe the events surrounding the establishment, operation, and closing of the unsanctioned SIS, and outline the lessons learned.

British Columbia↗
PubMed2003

Provider bias in the selection of non-nucleoside reverse transcriptase inhibitor and protease inhibitor-based highly active antiretroviral therapy and HIV treatment outcomes in observational studies.

OBJECTIVE: To compare the characteristics of patients prescribed non-nucleoside reverse transcriptase inhibitors (NNRTI) and protease inhibitors (PI), and evaluate treatment outcomes in a setting in which nevirapine has been preferentially recommended since 1998. METHODS: A population-based analysis of antiretroviral-naive adults who started highly active antiretroviral therapy (HAART) between 1 August 1996 and 31 July 2000, and who were followed until 31 March 2002. We compared baseline characteristics, and evaluated virological responses and mortality. RESULTS: Overall, 439 patients (28.8%) started HAART with NNRTI (94.1% used nevirapine), 100 (6.6%) used a double PI, and 983 (64.6%) used a single PI-based regimen. Substantial differences were observed between the baseline clinical characteristics of these populations. In adjusted analyses, in comparison with single PI therapy, only the use of NNRTI was associated with more rapid HIV-RNA suppression [relative hazard (RH) 1.42; 95% confidence interval (CI) 1.22-1.65; P < 0.001]. A total of 204 deaths were identified in the study population [42 (9.6%) NNRTI; 11 (11%) double PI; 151 (15.4%) single PI, respectively]. In adjusted analysis, NNRTI (RH 1.01; 95% CI 0.71-1.45) and double PI-based HAART (RH 0.74; 95% CI 0.40-1.39) had similar mortality rates to the single PI reference category. CONCLUSION: NNRTI use was associated with more rapid virological suppression, whereas similar rates of rebound and mortality were found. Nevertheless, major baseline differences existed between patients prescribed the various initial regimens. As such, it is likely that similar selection factors may explain why our findings contrast with several non-randomized studies showing worse clinical outcomes of patients prescribed nevirapine.

Adult↗
PubMed2003

Effect of medication adherence on survival of HIV-infected adults who start highly active antiretroviral therapy when the CD4+ cell count is 0.200 to 0.350 x 10(9) cells/L.

BACKGROUND: The safety of delaying highly active antiretroviral therapy (HAART) in HIV-infected patients is uncertain when the CD4+ cell count declines below 0.350 x 10(9) cells/L. OBJECTIVE: To evaluate the effect of baseline CD4+ cell count and adherence to HAART on survival rates. DESIGN: Prospective observational study. SETTING: Province-wide Canadian HIV/AIDS treatment program. PATIENTS: 1422 HIV-infected persons initiating HAART between 1 August 1996 and 31 July 2000 and followed through 31 March 2002. MEASUREMENTS: Patients were stratified by baseline CD4+ cell count and adherence level. Cumulative mortality rates were evaluated by using Kaplan-Meier methods and Cox regression-estimated adjusted relative hazards. RESULTS: Kaplan-Meier analyses showed no survival benefit of starting HAART at a CD4+ count of 0.200 x 10(9) cells/L or greater among adherent patients. Adjusted analysis showed that compared with adherent patients who initiated HAART at a CD4+ cell count of 0.350 x 10(9) cells/L or greater, nonadherent patients who initiated HAART when the CD4+ cell count was 0.200 to 0.349 x 10(9) cells/L had statistically elevated mortality rates (adjusted relative hazard, 2.56 [95% CI, 1.36 to 4.84]; P = 0.004). However, compared with adherent patients who initiated HAART at a CD4+ cell count of 0.350 x 10(9) cells/L or greater, adherent patients who initiated HAART when the CD4+ cell count was 0.200 to 0.349 x 10(9) cells/L had statistically similar mortality rates (adjusted relative hazard, 0.82 [CI, 0.45 to 1.49]; P > 0.2). CONCLUSIONS: Delaying HAART until the CD4+ cell count falls to 0.200 x 109 cells/L does not increase the mortality rate in HIV-infected patients with good medication adherence. Mortality rates increase if HAART is initiated below 0.200 x 10(9) cells/L. Also, nonadherent patients have higher mortality rates than adherent patients with similar CD4+ cell counts. Above a CD4+ cell count of 0.200 x 10(9) cells/L, medication adherence is the critical determinant of survival, not the CD4+ cell count at which HAART is begun.

Adult↗
PubMed2003

Higher baseline levels of plasma human immunodeficiency virus type 1 RNA are associated with increased mortality after initiation of triple-drug antiretroviral therapy.

We evaluated 1422 antiretroviral therapy (ART)-naive patients infected with human immunodeficiency virus (HIV) who initiated highly active antiretroviral therapy between 1 August 1 1996 and 31 July 2000 and were monitored until 31 March 2002. Patients were stratified on the basis of baseline levels of HIV RNA (<50,000, 50,000-99,999, and > or =100,000 copies/mL). Cox regression was used to determine independent predictors of time to death. After adjustment for adherence to ART and other potential confounders, baseline levels of HIV RNA of > or =100,000 copies/mL remained independently associated with mortality (adjusted relative hazard, 1.71; 95% confidence interval, 1.08-2.70; P=.023). If appropriately confirmed, these findings have important implications for the development of therapeutic guidelines.

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

Is there a baseline CD4 cell count that precludes a survival response to modern antiretroviral therapy?

OBJECTIVE: Therapeutic guidelines advise that 200-350 x 106 cells/l may approximate an irreversible threshold beyond which response to therapy is compromised. We evaluated whether non-immune-based factors such as physician experience and adherence could affect survival among HIV-infected adults starting HAART. METHODS: Analysis of 1416 antiretroviral naive patients who initiated triple therapy between 1 August 1996 and 31 July 2000, and were followed until 31 July 2001. Patients whose physicians had previously enrolled six or more patients were defined as having an experienced physician. Patients who received medications for at least 75% of the time during the first year of HAART were defined as adherent. Cumulative mortality rates and adjusted relative hazards were determined for various CD4 cell count strata. RESULTS: Among patients with < 50 x 106 cells/l the adjusted relative hazard of mortality was 5.07 [95% confidence interval (CI), 2.50-10.26] for patients of experienced physicians and was 11.99 (95% CI, 6.33-22.74) among patients with inexperienced physicians, in comparison to patients with > or = 200 x 106 cells/l treated by experienced physicians. Similarly, among patients with < 50 x 106 cells/l, the adjusted relative hazard of mortality was 6.19 (95% CI, 3.03-12.65) for adherent patients and was 35.71 (95% CI, 16.17-78.85) for non-adherent patients, in comparison to adherent patients with > or = 200 x 106 cells/l. CONCLUSION: Survival rates following the initiation of HAART are dramatically improved among patients starting with CD4 counts < 200 x 106 cells/l once adjusted for conservative estimates of physician experience and adherence. Our results indicate that the current emphasis of therapeutic guidelines on initiating therapy at CD4 cell counts above 200 x 106 cells/l should be re-examined.

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↗
PubMed2003

The potential public health and community impacts of safer injecting facilities: evidence from a cohort of injection drug users.

BACKGROUND: Although medically supervised safer injecting facilities (SIFs) remain untested in North America, their implementation is currently being debated. Reluctance of health policy makers to initiate a pilot study of SIFs may in part be hindered by outstanding questions regarding the potential community and public health impact of the intervention. Specifically, it is presently unknown if those at greatest risk of overdose and HIV transmission or those responsible for community impact of injection drug use will be willing to attend. METHODS: The current study was conducted to evaluate the proportion of injection drug users (IDU) willing to attend medically supervised SIFs, if they were available, among participants enrolled in the Vancouver Injection Drug User Study (VIDUS). The authors also evaluated factors associated with willingness to use a SIF using univariate and logistic regression analyses. Participants who were followed from June 2001 to June 2002 were eligible for the present analyses. RESULTS: Overall, 587 active IDU responded to a questionnaire during the study period. Among respondents, 215 (36.6%) expressed willingness to attend a SIF. Variables that were independently associated with willingness to attend a SIF in multivariate analyses included having difficulty accessing sterile syringes (adjusted odds ratio [AOR] = 2.07), requiring help injecting (AOR = 1.52), frequently injecting heroin (AOR = 1.81), sex trade work (AOR = 2.02), and injecting in public spaces (AOR = 2.00). CONCLUSIONS: Several variables that have recently been associated with overdose, syringe sharing, HIV and HCV incidence, and community impact of illicit drug use in this setting were associated with willingness to attend medically supervised SIFs. Although the impact of SIFs in North America can only be quantified by scientific evaluation, these data indicate a high potential for immediate community and public health benefits if SIFs were presently available.

Adult↗
PubMed2003

An external evaluation of a peer-run "unsanctioned" syringe exchange program.

In Vancouver, British Columbia, Canada, difficulty accessing syringes at night has been shown to be strongly associated with human immunodeficiency virus (HIV) risk behavior among the city's injection drug users (IDUs). On September 1, 2001, the Vancouver Area Network of Drug Users (VANDU) initiated an unsanctioned all-night needle-exchange program on a street corner in the heart of the neighborhood where many of the city's IDUs are concentrated. An external evaluation of the population reached by the VANDU exchange was performed through the Vancouver Injection Drug User's Study, a prospective cohort study of IDUs begun in 1996. Persons accessing syringes through the exchange were compared to those active injectors who acquired their syringes from other sources, including the city's fixed site exchange, which closes at 8:00 PM. Overall, 587 active IDUs were seen during the period September 2001 to June 2002; of these individuals, 165 (28.1%) reported using the VANDU exchange. In multivariate analyses, participants who used the VANDU table were more likely to frequently inject cocaine (adjusted odds ratio [AOR]=1.56; 95% confidence interval [CI]=1.00-2.44), inject in public (AOR=2.71; 95% CI=1.62-4.53), and require help injecting (OR=2.13; 95% CI=1.33-3.42). Interestingly, use of the table was also independently associated with safer syringe disposal (AOR=2.69; 95% CI=1.38-5.21). Results indicate that the unsanctioned exchange appears to have reached those IDUs at highest risk of HIV infection. Although the cross-sectional nature of the study design warrants caution, we also found that use of the nighttime exchange was strongly associated with higher rates of safe syringe disposal. The data suggest that drug user organizations can play a major role in reducing harm among their peers by reaching the highest risk drug users with harm reduction services. The findings also suggest that other forms of syringe-exchange programs should consider the benefits of offering fixed site nighttime service.

Adult↗
PubMed2003

Total lymphocyte count as a possible surrogate of CD4 cell count to prioritize eligibility for antiretroviral therapy among HIV-infected individuals in resource-limited settings.

OBJECTIVE: To characterize the value of total lymphocyte counts in predicting risk of death among patients initiating triple combination antiretroviral therapy. METHODS: Study subjects included antiretroviral-naive persons aged 18 years or older who initiated treatment with triple combination therapy between August 1 1996 and September 30 1999 in a population-based observational cohort of HIV-infected individuals. Total lymphocyte counts as well as CD4 count and plasma viral load were assessed at baseline. Separate Cox proportional hazards models were devised to evaluate the effect on survival of total lymphocyte count in lieu of or with CD4 count after adjustment for other prognostic factors including plasma viral load. RESULTS: A total of 733 antiretroviral-naive persons initiated triple drug combination antiretroviral therapy over the study period with a median follow-up of 29.5 months. In the first analysis, only baseline CD4 cell counts of 50-199 cells/microl or less than 50 microl were associated with an increased risk of mortality [adjusted relative risk (ARR) 2.90; 95% CI: 1.40, 5.98] and (ARR 6.30; 95% CI: 2.93, 13.54), respectively. When CD4 counts were excluded from the analysis as if unavailable, total lymphocyte count of between 0.8 and 1.4 G/I, and less than 0.8 G/I were both significantly associated with an increased risk of mortality (ARR 2.36; 95% CI: 1.16, 4.78) and (ARR 6.17; 95% CI: 2.93, 13.01), respectively. CONCLUSION: Total lymphocyte count may provide a simple and cost-effective alternative for prioritizing therapy initiation in resource-limited settings. Our results suggest that, if appropriately validated, judicious application of total lymphocyte counts could overcome one of the practical obstacles to more widespread provision of antiretroviral therapy in resource-poor settings.

Adolescent↗
PubMed2002

Virologic and immunologic response, clinical progression, and highly active antiretroviral therapy adherence.

A growing body of evidence suggests that a high degree of adherence is required to achieve and maintain a successful virologic response both in the short and long term. This holds true despite the definition of adherence or how it is measured. Reported differences in the degree of adherence required are likely due to differences in study design, difficulty measuring patient adherence, patient population studied, and the antiretroviral regimen studied. Virologic suppression and immunologic response often go hand in hand, but the impact of adherence on change in CD4 count tends to be delayed and, therefore, less apparent than the impact on HIV viral load. Degree of adherence has also been shown to be associated with AIDS-related morbidity, mortality, and hospitalizations.

Adolescent↗