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HIV seroprevalence among participants at a Supervised Injection Facility in Vancouver, Canada: implications… Tyndall, Mark W; Wood, Evan; Zhang, Ruth; Lai, Calvin; Montaner, Julio S; Kerr, Thomas Dec 18, 2006

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ralssBioMed CentHarm Reduction JournalOpen AcceResearchHIV seroprevalence among participants at a Supervised Injection Facility in Vancouver, Canada: implications for prevention, care and treatmentMark W Tyndall*1,2, Evan Wood1,2, Ruth Zhang2, Calvin Lai2, Julio SG Montaner1,2 and Thomas Kerr1,2Address: 1Department of Medicine, University of British Columbia, Vancouver Hospital, 2775 Laurel Street, Vancouver, V5Z 1M9, Canada and 2BC Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 1081 Burrard Street, Vancouver, V6Y 1Y6, CanadaEmail: Mark W Tyndall* - mtyndall@cfenet.ubc.ca; Evan Wood - ewood@cfenet.ubc.ca; Ruth Zhang - rzhang@cfenet.ubc.ca; Calvin Lai - clai@cfenet.ubc.ca; Julio SG Montaner - jmontaner@cfenet.ubc.ca; Thomas Kerr - tkerr@cfenet.ubc.ca* Corresponding author    AbstractNorth America's first government sanctioned medically supervised injection facility (SIF) wasopened during September 2003 in Vancouver, Canada. This was in response to a large open publicdrug scene, high rates of HIV and hepatitis C transmission, fatal drug overdoses, and poor healthoutcomes among the city's injection drug users. Between December 2003 and April 2005, arepresentative sample of 1,035 SIF participants were enrolled in a prospective cohort that requiredcompleting an interviewer-administered questionnaire and providing a blood sample for HIVtesting. HIV infection was detected in 170/1007 (17%) participants and was associated withAboriginal 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), previousincarceration (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 presentsan excellent opportunity to enhance HIV prevention through education, the provision of sterileinjecting equipment, and a supervised environment to self-inject. In addition, the SIF is an importantpoint of contact for HIV positive individuals who may not be participating in HIV care andtreatment.BackgroundIn response to a large open public drug scene, high ratesof HIV and hepatitis C transmission, fatal drug overdoses,and poor health outcomes among injection drug users,Vancouver established North America's first governmentsanctioned medically supervised safer injection facility(SIF) in September 2003 [1-3]. The SIF has been approveda comprehensive prospective strategy [4,5]. Initial find-ings from the evaluation have been published, includingevidence that the SIF has attracted a wide range of margin-alized injection drug users (IDUs) [6,7], has reduced drugrelated public disorder [8], and has been associated withreduced syringe sharing [9,10].Published: 18 December 2006Harm Reduction Journal 2006, 3:36 doi:10.1186/1477-7517-3-36Received: 29 August 2006Accepted: 18 December 2006This article is available from: http://www.harmreductionjournal.com/content/3/1/36© 2006 Tyndall et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Page 1 of 5(page number not for citation purposes)as a three year scientific evaluation by Health Canada witha predetermined set of outcomes to be evaluated throughWith respect to HIV, the focus of the SIF to date, as withother harm reduction initiatives, has been on reducingHarm Reduction Journal 2006, 3:36 http://www.harmreductionjournal.com/content/3/1/36HIV transmission through the provision of sterile syringesand providing a space where self-administered injectionscan be conducted in a clean and controlled environment[4,11]. It has been previously shown in this communitythat HIV infection has a disproportional impact on injec-tion cocaine users [12], women [13], and those of Aborig-inal ethnicity [14], and efforts to specifically engage andaccommodate these groups at the SIF are ongoing. Giventhe high representation of these groups at the SIF, it isanticipated that attending the SIF will result in reducedtransmission of HIV.The purpose of this analysis is to measure the prevalenceand correlates of baseline HIV among those who are usingthe SIF. This information is important to determine if theSIF could be used as a site for HIV related care and treat-ment. This is also important in order to measure the lon-gitudinal incidence of HIV transmission among thoseusing the SIF.MethodsAs part of a comprehensive evaluation strategy, a repre-sentative cohort of SIF users (SEOSI) was recruited andfollowed prospectively. The methods have been describedpreviously [5]. Briefly, the cohort includes SIF users whowere selected through a random number generation strat-egy. Each week between 16 and 32 two-hour time blockswere designated for recruitment between the openinghours of 10:00 a.m. and 4:00 a.m. seven days per week.During these random time periods 10 cards were distrib-uted to consecutive SIF users who were invited to visit theSEOSI cohort study office located one block from the SIF.There was a CAN$20 compensation provided if they werewilling to participate in the prospective study following afull explanation, providing a written informed consent,completing an interviewer-administered questionnaireand supplying a blood sample for HIV and hepatitis Ctesting. All SEOSI participants provide informed consentto link to the Insite database so that SIF use can be tracked,as well as informed consent to access administrativehealth record databases in the community. The study wasclosed to new participants as of March 31, 2005 at whichtime 1,035 people were enrolled in the cohort from 4,764individuals who had ever visited the SIF. A comparisonbetween all SIF users and SEOSI cohort participants hasshown statistically similar socio-demographic variables(all p > 0.5)[5]. The study was approved by the Universityof British Columbia/Providence Health Care EthicsBoard.To determine factors associated with HIV infection, bivar-iate analysis was performed using Pearson's Chi-squaretesting and Wilcoxon rank sum test. Logistic regressionvariable models were fit adjusting for variables that wereof interest a priori or that were statistically significant atthe p < 0.05 level in the bivariable analyses. The statisticalanalysis was performed using SPSS 12.0, and all reportedp-values are two sided.ResultsThis analysis includes data from the baseline recruitmentof 1,035 individuals who were randomly selected to par-ticipate in the SEOSI cohort between December 1, 2003and March 31, 2005. Of these, HIV testing was availableon 1007 (97%). The missing HIV results were attributedto difficulty in obtaining venous blood samples from 28of the participants. Among those tested, 170 of 1007(17%) were found to be HIV positive. Table 1 shows thedemographic characteristics of the participants stratifiedby HIV serostatus. In this bivariate comparison, HIV pos-itive status was associated with more years of drug inject-ing (p = 0.008), Aboriginal ethnicity (p < 0.001), dailycocaine injecting (p = 0.020), borrowing used needles/syringes (p < 0.001), methadone maintenance treatment(p = 0.018), sex work (p = 0.051), and history of incarcer-ation (p = 0.004). In this cohort, HIV infection was notassociated with gender, residence in the Vancouver'sDowntown Eastside, daily heroin injection, daily crystalmethamphetamine injection, public drug use, requiringhelp with injecting, sharing other drug using equipment,or binge drug use.In the logistic regression analysis shown in Table 2, HIVpositive status was independently associated with Aborig-inal ethnicity (adjusted Odds Ratio [aOR] 2.70, 95% Con-fidence Interval [CI] 1.84, 3.97), borrowing used needles/syringes (aOR = 2.00, 95% CI:1.37, 2.93), history of incar-ceration (aOR = 1.87, 95% CI:1.11, 3.14), and dailycocaine injection (aOR 1.42, 95% CI:1.00, 2.03).DiscussionThe overall HIV seroprevalence among a random cohortof injection drug users attending the SIF was 17%. Thiswas not unexpected as high rates of HIV infection amonginjection drug users has been reported in this communityfor over a decade [1,12]. However, the random selectionprocess used to assemble this cohort may be more repre-sentative of active injection drug users in this communitywhen compared with previous estimates that were basedon non-random recruitment. The variables associatedwith HIV infection in this cohort; Aboriginal ethnicity,borrowing used needles, incarceration, and cocaine use,are consistent with characteristics previously described inthis population.The disproportionately high HIV prevalence among Abo-Page 2 of 5(page number not for citation purposes)analysis was also performed to examine factors that wereindependently associated with HIV infection. The multi-riginal people has been attributed to the convergence ofenvironmental, social and behavioral factors that increaseHarm Reduction Journal 2006, 3:36 http://www.harmreductionjournal.com/content/3/1/36vulnerability to illicit drug use and HIV infection [14,15].Providing culturally relevant services for Aboriginal peo-ple is a priority for this community as the uptake of serv-ices and supports is suboptimal. In this context, it isencouraging that the SIF has attracted a relatively largenumber of Aboriginal people, and can provide an impor-The association between intensive cocaine use and HIVinfection has been well described in this community andinjection cocaine is consistently found to increase HIVtransmission [12,16]. The propensity of many IDUs to usecocaine in high-intensity episodic patterns contributes tothe high risk of HIV transmission associated with cocaineTable 1: Prevalence of HIV stratified by socio-demographic and behavioural variables.Characteristic HIV-Positive n (%) HIV-Negative n (%) Odds Ratio (95% CI) p valueAgeMedian (IQR) 37.9 (10.3) 38.6 (12.1) .914GenderMale 113 (66.5) 612 (73.1) 0.73 (0.51 – 1.04) .078Female 57 (33.5) 225 (26.9)EthnicityAboriginal 55 (32.4) 140 (16.7) 2.38 (1.65 – 3.44) <.001Other 115 (67.6) 697 (83.3)Reside in DTESYes 120 (70.6) 570 (68.1) 1.12 (0.78 – 1.61) .524No 50 (29.4) 267 (31.9)Daily Cocaine InjectionYes 68 (40.0) 258 (30.8) 1.50 (1.07 – 2.10) .020No 102 (60.0) 579 (69.2)Daily Heroin InjectionYes 78 (45.9) 435 (52.0) 0.78 (0.56 – 1.09) .148No 92 (54.1) 402 (48.0)Daily Crystal Meth InjectionYes 3 (1.8) 31 (3.7) 0.47 (0.14 – 1.55) .202No 167 (98.2) 806 (96.3)Public drug useYes 128 (75.3) 605 (72.3) 1.17 (0.80 – 1.71) .421No 42 (24.7) 232 (27.7)Ever borrow needles/syringesYes 122 (71.8) 455 (54.4) 2.13 (1.49 – 3.06) <.001No 48 (28.2) 382 (45.6)Share other equipmentYes 104 (61.2) 477 (57.0) 1.19 (0.85 – 1.67) .314No 66 (38.8) 360 (43.0)Require help injectingYes 134 (78.8) 619 (74.0) 1.31 (0.88 – 1.95) .183No 36 (21.2) 218 (26.0)Binge drug useYes 109 (64.1) 525 (62.7) 1.06 (0.75 – 1.50) .732No 61 (35.9) 312 (37.3)Addiction TreatmentYes 92 (54.1) 361 (43.1) 1.56 (1.12 – 2.17) .009No 78 (45.9) 476 (56.9)On Methadone CurrentlyYes 48 (28.2) 168 (20.1) 1.57 (1.08 – 2.28) .018No 122 (71.8) 669 (79.9)Sex-trade EverYes 78 (45.9) 317 (37.9) 1.39 (1.00 – 1.94) .051No 92 (54.1) 520 (62.1)History of incarcerationYes 150 (88.2) 658 (78.6) 2.04 (1.24 – 3.35) .004No 20 (11.8) 179 (21.4)Note: IQR = inter-quartile range, DTES = Downtown EastsidePage 3 of 5(page number not for citation purposes)tant point of contact for those who may be reluctant toparticipate in other health and social services.use [17]. This pattern of drug use may be particularlyinfluenced at the SIF as only one injection is allowed atHarm Reduction Journal 2006, 3:36 http://www.harmreductionjournal.com/content/3/1/36each visit. This may pre-empt a prolonged "drug-run" orindividuals may decide to use the SIF specifically as a wayto interrupt a current period of intensive drug use. Studiesare currently underway to better understand the impacton the SIF on drug use patterns. These results however doshow that cocaine users do attend the SIF and that earlierconcerns that people would not use cocaine at the SIFwere unfounded [6].A history of incarceration is often an indicator of socialisolation and the majority of convictions seen in this pop-ulation are on the basis of illegal drug infractions. Therelationship between incarceration and increased HIVtransmission among injection drug users is a major area ofdebate for Canada and globally [18]. In this cross-sec-tional study, it is not possible to determine the date of HIVinfection and its temporal relationship with prior incar-ceration, however there are risk behaviors that do occurduring the time of incarceration and more efforts toreduce the harms to inmates are needed [19-21].In addition to connecting with HIV positive people, theSIF functions as an important entry point to provide pri-mary HIV prevention. One of the primary objectives of theSIF is to develop consistent contact with people at risk ofHIV who are often isolated and marginalized. The SIFoffers an engaging, low threshold environment and partic-ipants are encouraged to attend regularly. During the vis-its there is an opportunity to offer HIV preventioneducation through the use of sterile injection techniquesand to emphasize the importance of clean needles as wellas opportunities for referral to addiction services includ-ing counseling, detoxification, and methadone programs[6].It would be extremely unlikely to be exposed to HIV whileinjecting at the SIF. All participants are supplied with newneedles/syringes, alcohol swabs, elastic tourniquets, andcookers if required. All injections occurring within the SIFare restricted to self-injections and this eliminates the highrisk behavior of people injecting each other [22]. How-this group of IDUs are needed. Despite the high attend-ance at the SIF, for many participants the majority of injec-tions occur in other locations that may lead to risky druguse practices. The site is currently operating at capacitywith approximately 700 visits per day. Increased hours ofoperation (i.e. from 18 to 24 hours per day) and greatercapacity to accommodate more injection drug userswithin the SIF would increase coverage.There are a number of limitations with this study. Thecross-sectional nature of the analysis does not allow thetiming of HIV transmission to be determined and thussome of the associated risks may have occurred after theHIV infection. Secondly, some of the risk variables werebased on self-report and this may have been biased bysocially desirable responses. Thirdly, the participants inthe study were selected from those who had already madea decision to use the SIF and are not necessarily represent-ative of the injection drug using community.Our results demonstrate a 17% prevalence of HIV infec-tion among a representative cohort of IDUs who attendVancouver's SIF. The SIF has successfully attracted a groupof marginalized HIV infected individuals and thereforeprovides a unique opportunity to improve access tohealth services and HIV care and treatment [23]. Further-more, the capacity to prevent new cases of HIV throughenhanced prevention messages and interventions at theSIF has great potential. Many cities are confronting theserious health and social consequences of poorly control-led injection drug use among marginalized citizens andsubsequent outbreaks of HIV infection. The SIF in Van-couver has provided a valuable addition to existing serv-ices for injection drug users and should be considered inother communities.AcknowledgementsThe authors wish to thank the staff of the InSite SIF and Vancouver Coastal Health (Chris Buchner, Heather Hay, David Marsh). We also thank Debo-rah Graham, Aaron Eddie, Peter Vann, Dave Isham, Steve Kain, and Suzy Coulter for their research and administrative assistance. The SIF evaluation has been made possible through a financial contribution from Health Can-Table 2: Multivariate Logistic Regression Analysis of Factors associated with baseline HIV Infection.Characteristic Adjusted Odds Ratio 95% C.I. p-valueAboriginal ethnicityYes vs No 2.70 1.84 – 3.97 <.001Ever borrow needles/syringesYes vs No 2.00 1.37 – 2.93 <.001History of incarcerationYes vs No 1.87 1.11 – 3.14 .019Daily Cocaine UseYes vs No 1.42 1.00 – 2.03 .050Page 4 of 5(page number not for citation purposes)ever, this restriction will deter those who do require helpinjecting from attending the SIF and strategies to reachada, though the views expressed herein do not represent the official poli-cies of Health Canada.Publish with BioMed Central   and  every scientist can read your work free of charge"BioMed Central will be the most significant development for disseminating the results of biomedical research in our lifetime."Sir Paul Nurse, Cancer Research UKYour research papers will be:available free of charge to the entire biomedical communitypeer reviewed and published immediately upon acceptancecited in PubMed and archived on PubMed Central Harm Reduction Journal 2006, 3:36 http://www.harmreductionjournal.com/content/3/1/36References1. 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