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Increases in the availability of prescribed opioids in a Canadian setting Nosyk, Bohdan; Marshall, Brandon David Lewis; Fischer, Benedikt; Montaner, Julio; Wood, Evan; Kerr, Thomas Nov 1, 2012

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Increases in the availability of prescribed opioids in a CanadiansettingB. Nosyk1, B.D.L. Marshall1,2, B. Fischer3,4, J.S.G. Montaner1,5, E. Wood1,5, and T. Kerr1,51British Columbia Centre for Excellence in HIV/AIDS, St. Paul’s Hospital, 608-1081 BurrardStreet, Vancouver, BC, CANADA, V6Z 1Y62Department of Epidemiology, Columbia University Mailman School of Public Health, 722 W 168thStreet, New York, NY, USA, 10032-37273Faculty of Health Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BritishColumbia, Canada, V5A 1S64Centre for Addictions and Mental Health, 33 Russell St., Toronto, Ontario, Canada M5S 2S15Department of Medicine, University of British Columbia, St. Paul’s Hospital, 608-1081 BurrardStreet, Vancouver, BC, CANADA, V6Z 1Y6AbstractBackground—The nonmedical use of prescribed opioids (POs) has increased across NorthAmerica over the past decade. Our objective was to identify changes in the availability of POs andother illicit drugs among drug users in a Canadian setting.Methods—Information on the availability of illicit drugs was collected in standardizedinterviews from a large observational research program involving illicit drug users in Vancouver,British Columbia from 2006–2010. The primary outcome was the perceived availability of a set ofsix POs (aspirin/oxycodone, hydromorphone, oxycodone, morphine, acetaminophen/codeine andmethadone) among individuals reporting ever using POs. Availability was measured in threelevels: not available, delayed availability (available ≥10min.), and immediate availability(available <10min.). Multivariate ordinal logistic regression models were executed to estimate thetrend in PO availability, controlling for individual characteristics hypothesized to influenceavailability.Results—1,871 individuals were followed during the study period (2006–2010), including583(31.2%) women. The availability of POs increased over time, regardless of changes in thecharacteristics of cohort entrants. These increases were observed while the availability oftraditional drugs of abuse (e.g., heroin and cocaine) remained constant. The adjusted odds of© 2012 Elsevier Ireland Ltd. All rights reserved.Send correspondence to: Bohdan Nosyk, B.C. Centre for Excellence in HIV/AIDS, University of British Columbia, St. Paul’sHospital, 613-1081 Burrard Street, Vancouver, B.C., V6Z 1Y6, Canada, Tel: (604) 806-8649, Fax: (604) 806-9044,bnosyk@cfenet.ubc.ca.Contributors: Authors BN, EW and TK and BF designed the study protocol. BN wrote the first draft of the manuscript. BNundertook the statistical analysis with significant scientific input from BDLM and TK. TK, EW and JSGM were responsible for datacollection. All authors contributed to and have approved the final manuscript.Conflict of interest: All authors declare that they have no conflicts of interest.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to ourcustomers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review ofthe resulting proof before it is published in its final citable form. Please note that during the production process errors may bediscovered which could affect the content, and all legal disclaimers that apply to the journal pertain.NIH Public AccessAuthor ManuscriptDrug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.Published in final edited form as:Drug Alcohol Depend. 2012 November 1; 126(1-2): 7–12. doi:10.1016/j.drugalcdep.2012.03.010.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author Manuscriptdelayed availability vs. unavailability were between 34% (hydromorphone) and 71%(acetaminophen/codeine) greater in each calendar year.Discussion—The availability of POs among drug users in a Canadian setting increasedmarkedly over a relatively short timeframe, despite persistent and high availability of heroin andcocaine. Further study is required to determine the context of use of POs, associated harms, aswell as policy responses to increasing availability.KeywordsPrescribed opioids; availability; oxycodone; hydromorphone; methadone; illicit drugs1.0 IntroductionWhereas the 1980s and 1990s bore witness to epidemics of crack cocaine and heroin use inmany inner city areas, the nonmedical use of prescribed opioids (POs) is emerging as anincreasing concern. Rising rates of use have been documented in the US, most notablyamong youth and young adults. Among high school seniors, Hydrocodone abuse was secondonly to marijuana abuse (Volkow and McLellan, 2011). A 7-fold increase in drug treatmentadmissions involving opioids other than heroin was observed between 1998 and 2009.(SAMHSA TEDS Database, 2011). Emergency department visits involving non-medical useof prescription drugs increased to a greater extent than other illicit drugs, with Oxycodone(175,949 in 2009; a 242.2% increase from 2004) and Hydrocodone (104,490 in 2009; a124.5% increase from 2004) among the highest increases. Finally prescribed opioid-relatedoverdose deaths increased from 2000 in 1999 to 14,800 in 2008. (Centers for DiseaseControl and Prevention, 2011). Opioid overdose is now the second leading cause ofunintentional death in the United States, second only to motor vehicle accidents (NationalCentre for Injury Prevention and Control, 2010), which prompted the Centers for DiseaseControl and Prevention to label PO overdose as a national epidemic (Centers for DiseaseControl and Prevention, 2011).There is accumulating evidence of similar trends in use in Canadian settings. An early studyconducted in Vancouver identified a range of prescription medications available for illicitsale, including POs such as acetaminophen/codeine, aspirin/oxycodone, meperidine,hydromorphone, morphine, and Anileridine (no longer manufactured in North America;Sajan, 1998). In a 2004 report on a cohort of methadone maintenance treatment (MMT)patients in Ontario, Brands et al. (2004) reported that 83% of all patients had been usingPOs, with or without heroin, upon admission. The OPICAN study, conducted in fiveCanadian cities, revealed that nonmedical use of POs was far more prevalent than the use ofheroin in every setting except Vancouver and Montreal (Fischer et al., 2005). From 2002 to2005, a relative increase of 24% was observed in the proportion of the street drug usingpopulation who used non-medical POs only (Popova et al., 2009). Recent studies havedescribed increases in the amounts of opioids prescribed across Canada (Fischer et al.,2011), increasing opioid utilization among recipients of social assistance in Ontario (Gomes,2011a) and street users in Montreal (Bruneau et al., 2012; Roy et al., 2011), a strongindependent relationship between PO dose and opioid-related mortality (Gomes, 2011b),high variation in opioid prescribing among Ontario physicians (Dhalla, 2011) and high ratesof non-methadone opioid use among clients in methadone maintenance treatment in Ontario(Kurdyak et al., 2011).Despite this rapidly growing literature documenting problematic PO use in North America,few studies have endeavored to ascertain temporal trends in street-level availability of POsand other illicit drugs (e.g., cocaine and heroin). Our objective, therefore, was to examineNosyk et al. Page 2Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author Manuscriptthe availability of prescribed opioids and other illicit drugs among street users in Vancouver,British Columbia between 2006 and 2010.2.0 Methods2.1 Study designData for this analysis were derived from the baseline assessments of a series of ongoingopen prospective cohort studies involving illicit drug users, including the At-Risk YouthStudy (ARYS), the AIDS Care Cohort to evaluate Exposure to Survival Services(ACCESS), and the Vancouver Injection Drug Users Study (VIDUS). The VIDUS studybegan enrollment in May 1996 and recruits individuals through word of mouth, street out-reach, and referrals. Recently, the original VIDUS cohort was divided into two separatestudies: VIDUS now follows HIV-negative participants and its sister study ACCESS followsHIV-positive drug users based in the Greater Vancouver area (Strathdee et al., 1998; Woodet al., 2009). The At-Risk Youth Study began in late 2005 and is made up of street-involvedyouth who report use of drugs other than or in addition to cannabis and are aged 14 to 26(Wood et al., 2006).Sampling and follow-up methodologies have been described in detail previously (Strathdeeet al., 1997; Tyndall et al., 2003; Wood et al., 2006). Specific eligibility criteria werespecified in other articles; however, general eligibility across all three cohorts required ageof at least 14 years, Greater Vancouver region residence, and the provision of informedconsent. At baseline, participants complete an interviewer-administered questionnaire thatelicits information pertaining to sociodemographic characteristics, drug use, treatmentutilization, and HIV risk behaviours. Nurses also assessed participants for various healthconditions, and obtain blood specimens for HIV and Hepatitis C Virus (HCV) serology, andHIV disease monitoring (e.g., CD4 counts, HIV-1 RNA) where appropriate. Participantsreceive $20 CAD for each visit. While combining data from studies with different inclusioncriteria may present some challenges, we note that all studies rely on harmonizedrecruitment and data collection tools. These studies have been approved by the University ofBritish Columbia/Providence Health Care Research Ethics Board.2.2 Participants and measuresQuestions assessing the availability of illicit drugs were first added to the baseline studyinstrument for the ARYS, ACCESS and VIDUS cohort studies in late 2005. All participantswho completed the baseline interview after this date were eligible for inclusion. The studyperiod was defined as the five-year interval ending in December 31st, 2010. The availabilityof a set of 12 substances (crack cocaine, heroin, powder cocaine, crystal methamphetamine,marijuana, aspirin/oxycodone, hydromorphone, oxycodone, morphine, acetaminophen/codeine and methadone), acquired illicitly, were assessed at five levels: (1) score within 10minutes; (2) score within 90 minutes; (3) score within a day; (4) score in more than a day;(5) could not score this drug.We assessed changes in the availability of these drugs over the study period, withavailability being an aspect of supply, rather than demand for the substances in question.Given that individual characteristics could influence access to a given illicit drug, and thesefactors may have changed among cohort entrants over the study period, we controlled forthese factors by estimating the independent effect of calendar year on the availability ofillicit drugs among cohort entrants. Further, respondents were asked to provide assessmentsof availability regardless of whether they had ever used the substance. We includedassessments on availability from individuals who reported having used the substance inquestion.Nosyk et al. Page 3Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptWe hypothesized that a number of factors were potentially associated with availability.Aside from age and gender, we hypothesized unstable housing (defined as living in a singleoccupancy room hotel, a treatment or recovery house, jail, shelter or hostel, or having nofixed address for the last six months), daily use of POs, drug dealing involvement, sex workinvolvement, and geographic proximity to Vancouver’s Downtown Eastside (DTES) wouldeach influence how quickly an individual may access illicit drugs. Housing instability maybe indicative of greater mobility and therefore irregular contacts with suppliers, while dailyuse and dealing status are clearly indicative of stronger contact with a given drug supplychain. Involvement in sex work, potentially in exchange for illicit drugs, may also increasethe ease of availability of illicit drugs. Vancouver’s DTES is the most impoverishedneighborhood in Canada, and home to a high concentration of illicit drug use (Wood andKerr, 2006), and therefore proximity to this area may predict easier access to drugs. For thelatter, we considered several related variables, including current DTES residence, any DTESresidence in the past 6 months, regular visits to the DTES and indication of purchasing illicitdrugs in the DTES, and selected the covariate that provided the best model fit, usingAkaike’s and Bayes’ information criteria, and the largest effect size. Unless otherwiseindicated, variables refer to behaviours or activities in the past six months from the date ofthe baseline interview. In addition, we included cohort indicators, given that the assessmentswere drawn from three separate cohort studies with different aims and target populations.2.3 Statistical AnalysisAs a first step, we plotted univariate trends in the availability of each drug assessed inbaseline data from participants entering the cohorts in different years. We then constructedordinal logistic regression models to determine the odds of delayed and immediateavailability, controlling for other factors. The proportional odds assumption was tested usingthe Score test. Given low levels of responses for availability in <90minutes, <1 day and >1day, we combined these categories, thus providing us with a three-level, ordered outcomevariable: not available; delayed availability (available in ≥10 minutes) and immediateavailability (available in <10 minutes). We proceed with this terminology from this pointonward. Regression models for the availability of each substance were constructed withmanual stepwise elimination. For dichotomous variables, adjusted odds ratios are interpretedas the increase/decrease in the odds of the higher availability category for a 1-unit increasein the covariate (in comparison to the stated reference group). All analyses were executedusing SAS version 9.2.3.0 Results3.1 Summary statisticsSummary statistics on the covariates included in the analysis are provided in Table 1. A totalof 1871 individuals were recruited into the ARYS [N = 712 (38.1%)], ACCESS [N = 536(28.7%)] and VIDUS [N = 623 (33.3%)] cohorts during the study period; 31% were femaleand 37% were 25 or under (median age: 33.7; interquartile range: 22.7, 44.3). The majorityof individuals reported living in unstable housing (52%), 37.8% reported dealing drugs and8.3% reported being engaged in sex work in the past 6 months. Past use of each of the majorclasses of substances was high; 66.3% the cohort reported ever having used POs in the past.Finally, in each calendar year, between 123 (6.6%) in 2010 and 643 (34.4% in 2006individuals entered the study and completed baseline questionnaire packages.3.2 Univariate trends in availabilityTrends in the immediate availability of the illicit drugs assessed are plotted in Figure 1.While the immediate availability of heroin, crack cocaine, powder cocaine, crystalmethamphetamine and marijuana were high and remained constant throughout the studyNosyk et al. Page 4Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author Manuscriptperiod (Figure 1), the immediate availability of POs all increased between 2006 and 2010.Increases in the immediate availability of aspirin/oxycodone and hydromorphone were themost pronounced, increasing by 26.7% and 19.8%, respectively, for these substances duringthe study period. Immediate availability of aspirin/oxycodone increased from 11.2% in 2006to 37.9% in 2010; hydromorphone increased from 21.6% to 41.4%, and acetaminophen/codeine from 17.2% to 39.7%. During this same period, the proportions of individualsreporting that the set of POs were not available dropped 10–20%, most notably in 2007(Figure 2).3.3 Multivariate analysisResults of the multivariate analysis are provided in Table 2. As the score test indicated oddsratios were not proportional between the levels of availability, we fitted separate logisticregression models assessing the odds of delayed availability vs. unavailable and immediateavailability vs. delayed availability. Controlling for other covariates, the odds of delayedavailability was between 34.0% (hydromorphone) and 71.0% (acetaminophen/codeine)greater in each given calendar year, compared to being unavailable. Drug dealing status wassignificantly associated with ease of availability for each of the substances assessed, whiledaily use was associated with higher odds of immediate availability (compared to delayedavailability) of all but acetaminophen/codeine and methadone. Morphine, oxycodone andacetaminophen/codeine were generally more immediately available to older individuals,particularly those over 45, while female gender, unstable housing and engagement in sexwork and buying drugs in the DTES were not associated with availability when adjusting forother factors. Similarly constructed regression models were estimated for each of the othersubstances presented in Figure 1 - no significant trends in changes in availability were found(data not shown).4.0 DiscussionAmong illicit drug users in Vancouver, Canada, the immediate availability of POs increasedsignificantly from 2006 to 2010. These increases persisted after adjustment for changes inthe characteristics of individuals entering the cohorts under study. Our finding suggestingincreased presence of POs within illicit drug markets is consistent with a diverse set ofstudies undertaken in North America indicating rising PO use (Volkow and McLellan, 2011;Fischer et al., 2005; Popova et al., 2009; Rosenblum, 2011). However, to our knowledge,this is the first study to document increased availability of POs alongside high and stableavailability of other more traditional drugs of abuse (including heroin).4.1 Insights into the market for illicit drugsLike any other market for consumer products, the market for illicit drugs has proliferatedwith a greater variety of options available to buyers. One noteworthy finding is theuninterrupted ease of availability of the more traditional illicit drugs found in Vancouver.Illicit drugs have remained readily available to drug users while policing intensity andexpenditures on enforcement have continued to rise (BC Stats, 2011), and the period understudy has featured several highly-publicized violent conflicts among rival drug gangs,reportedly due to breaks in upstream supply chains (CTV News Report, 2009). Thedurability of the supply and use of illicit drugs in Vancouver was previously demonstratedduring a police crackdown (Wood et al., 2004) and following a large seizure of heroin in theport of Vancouver (Wood et al., 2003). However, in 2001, the effects of an alleged heroindrought was observed in Vancouver and in other settings served by producers within GoldenTriangle region, and within Vancouver the drought was associated with short-term decreasesin three independent markers of heroin use (Wood et al., 2006). The reasons for this droughthave been debated: several commentators believe these changes in heroin use to be a resultNosyk et al. Page 5Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author Manuscriptof upstream interruptions in production (Wood et al., 2006). Although high levels of heroinuse were quickly restored (Marshall et al., 2011), the increases in PO availability alongsidepersistent availability of heroin could reflect fluctuating purity of heroin and correspondingincreases in demand for POs.The supply of traditional drugs of abuse is understood to be maintained through adjustmentsin drug purity - interruptions in the supply chain result in lower-purity product distributed atthe retail level (Caulkins, 2006). POs, however, represent an interesting contrast, as they aremanufactured by pharmaceutical companies, prescribed by physicians, dispensed from localpharmacies, and have a composition that cannot be easily altered. These characteristicssuggest the supply of POs may be more effectively controlled, particularly if the finding thatPO users obtain the drugs directly or indirectly through regular pharmacy dispensation(Volkow et al., 2009), is universally true. However, this claim remains to be verified insettings involving long-term or polysubstance users in Canada and elsewhere, and ongoingreports of pharmacy break-ins, prompting policy response in British Columbia (BC Collegeof Pharmacists, 2011) suggest that regulatory changes at the prescribing and dispensationlevel may not fully address this problem.4.2 Implications for medical careIn light of the presumed supply of non-medically used POs through the medical system, anumber of recommendations to control the diversion of POs have been proposed, including:enhanced clinical teaching and training practices; standardized screening procedures andbest practice guidelines for managing patients with chronic non-cancer pain; indications forwhen and how long to prescribe opioid analgesics; indications for when short vs. long actingopioids should be prescribed; appropriate use of urine screening procedures to manage riskof diversion, abuse and addiction; the use of patient contracts; state prescription drugmonitoring programs to reduce doctor shopping; as well as continuation and discontinuationcriteria (Chou et al., 2009). These types of considerations by Canadian provincial Collegesof Physicians are clearly in need. Response to these matters has also come from drugcompanies; the US Food and Drug Administration recently approved a new formulation ofoxycodone designed to discourage misuse and abuse (Food and Drug Administration, 2010).Our results indicating the increasing ease of availability of diverted methadone is somewhatconcerning, as the potential backlash from this finding may trigger a policy response thatwould affect availability to those who require it. While each of the other opioids covered inthis analysis are prescribed for the management of pain, methadone has been effectivelyused to treat opioid dependence for over 40 years (Kreek et al., 2010). While it was notpossible to assess whether methadone was diverted from prescriptions with indications forpain or opioid dependence, evidence of methadone diversion can compromise both theavailability of methadone treatment, as well as the quality of care provided to clientsengaged in substitution treatment. Policies on take-home doses of methadone treatment inBC (currently not recommended beyond 7 days) were formulated primarily to minimize thepublic health risks related to methadone diversion (Ruel and Hickey, 1993). However, take-home doses may allow stabilized patients greater freedom in attending to family life,employment or other productive endeavors. In British Columbia, take-home doses are moreoften prescribed in rural areas (Nosyk et al., 2010), and may be a necessary component inthe reintegration of clients into society, as co-payments are required once an individual gainsemployment. Studies conducted in the United States have demonstrated success with longtake-home doses (up to 1 month) in stabilized, responsive patients (Salsitz et al., 2000;Harris et al., 2006). Evidence on the public safety issues regarding take-home doses shouldbe balanced against evidence that supports its effectiveness.Nosyk et al. Page 6Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author Manuscript4.3 Contexts of street use of prescribed opioidsWhile we’ve described and discussed the increasing supply of prescribed opioids, thedemand, and context of use of these substances requires closer consideration. Davis andJohnson (2008) provided a more nuanced perspective on the matter in an ethnographicanalysis of 586 street drug users in New York City. This study revealed that subjects in thisstudy were classified according to whether they diverted POs or used POs to relieve pain orwithdrawal rather than for euphoria. PO diversion was associated with frequency of PO use,whether POs were obtained from doctors/pharmacies or from drug dealers and familymembers. Policy and programmatic responses should acknowledge that POs may be used asa primary drug of abuse, as a temporary solution to opioid withdrawal, or as genuine painrelief. Greater insight into the contexts of street use in Vancouver and elsewhere in Canadaare thus clearly needed to inform policy and programmatic responses.4.4 LimitationsOur analysis is not without limitations. Primarily, the extent to which the results aregeneralizable to the drug using population in British Columbia is uncertain, as the cohortsunder study were not explicitly sampled randomly from the population of drug users inVancouver, BC. Further, while we’ve attempted to control for the potentially changing mixof participants entering the cohorts during the study period, given the observational nature ofthis study, there is always a possibility that there may be residual confounding that mayeither increase, or decrease, the true magnitude in change of availability of each of the drugsassessed. The consistency of our findings with other studies of diverse designs andpopulations under study however support the direction of our findings. As well, we wereunable to assess fluctuations in drug purity, which may in part explain the trends observedherein. Future studies should seek to assess a range of questions regarding the determinantsof the demand and supply of POs, including whether changing heroin purity affects theavailability and use of POs.The availability of POs among the study population increased markedly over a relativelyshort timeframe. This increase occurred despite the high and stable availability of other,more traditionally used illicit drugs, including heroin. Further study is required to determinethe context of use of POs and, subsequently, appropriate policy and programmaticresponses.AcknowledgmentsThe authors thank the study participants for their contribution to the research, as well as current and pastinvestigators and staff. We would like to thank Deborah Graham, Peter Vann, Caitlin Johnston, Steve Kain, andCalvin Lai for their research and administrative assistance.Role of funding source: Funding for this study was provided by National Institutes of Health (NIH) grants R01-DA011591 and R01-DADA031727 and a Canadian Institutes of Health Research (CIHR) grant RAA-79918.Thomas Kerr is supported by a Scholar Award from the Michael Smith Foundation for Health Research (MSFHR)and an Investigator Award from the CIHR. Bohdan Nosyk isa CIHR Bisby Fellow, and also supported by apostdoctoral fellowship from the Michael Smith Foundation for Health Research. Brandon Marshall is supported bypostdoctoral fellowships from the CIHR and the International AIDS Society/National Institute on Drug Abuse. Allfunding bodies had no further role in study design; in the collection, analysis and interpretation of data; in thewriting of the report; or in the decision to submit the paper for publication.ReferencesBrands B, Blake J, Sproule B, Gourlay D, Busto U. Prescription opioid abuse in patients presenting formethadone maintenance treatment. Drug Alcohol Depend. 2004; 73:199–207. [PubMed: 14725960]Nosyk et al. Page 7Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptBruneau J, Roy E, Arruda N, Zang G, Jutras-Aswad D. 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Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptFigure 1. Percentage of ever-users of each drug indicating immediate availability ** Immediately available = available within 10 minutes. Data are derived from baselineinterviews of participants entering the cohorts each year.Nosyk et al. Page 11Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptFigure 2.Percentage of ever-users indicating prescribed opioids were not availableNosyk et al. Page 12Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptNosyk et al. Page 13Table 1Descriptive characteristics of illicit drug users (N=1871)Covariate N (%)Female gender 583 (31.2)Age: < 25 695 (37.2) 25 – 35 278 (14.9) 35 – 45 466 (24.9) > 45 432 (23.1)Drug dealing* 703 (37.8)Sex work* 155 (8.3)Unstable housing* 969 (52.0)Current DTES residence 812 (43.4)DTES residence* 650 (34.7)Regular DTES visits* 448 (23.9)Purchased drugs in DTES* 1263 (67.5)VIDUS Cohort 623 (33.3)ACCESS Cohort 536 (28.7)ARYS cohort 712 (38.1)Year of cohort entry: 2006 643 (34.4) 2007 329 (17.6) 2008 286 (15.3) 2009 465 (24.9) 2010 123 (6.6)Self-reported ever use in lifetime: Heroin 1374 (73.8) Crack cocaine 1042 (55.9) Powder cocaine 1653 (88.7) Crystal methamphetamine 1000 (53.7) Prescribed opioids (PO) 1235 (66.3)DTES: Downtown Eastside.*refers to activities in the past six months.Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.NIH-PA Author ManuscriptNIH-PA Author ManuscriptNIH-PA Author ManuscriptNosyk et al. Page 14Table 2Results of multivariate analysis on the availability of prescribed opioids among ever users (N=1235)aspirin/oxycodonehydromorphonemorphineoxycodoneacetaminophen/codeineMethadoneAOR (95%CI)AOR (95%CI)AOR (95%CI)AOR (95%CI)AOR (95%CI)AOR (95%CI)Calendar year^Delayed vs. Not avail1.45 (1.23, 1.70)1.34 (1.15, 1.57)1.38 (1.20, 1.58)1.67 (1.45, 1.92)1.71 (1.47, 2.00)1.53 (1.30, 1.79)Immediate vs. Delayed1.10 (0.91, 1.32)1.11 (0.94, 1.31)1.06 (0.92, 1.23)1.00 (0.85, 1.19)0.99 (0.83, 1.17)0.86 (0.72, 1.03)Age: <25 - ref25–35Delayed vs. Not avail1.13 (0.68, 1.88)0.83 (0.50, 1.40)0.86 (0.49, 1.53)Immediate vs. Delayed2.70 (1.58, 4.62)2.11 (1.18, 3.80)2.79 (1.54, 5.05)35–45Delayed vs. Not avail1.21 (0.77, 1.90)0.62 (0.39, 0.99)0.76 (0.46, 1.25)Immediate vs. Delayed3.08 (1.90, 5.00)2.89 (1.69, 4.94)3.34 (1.96, 5.67)>45Delayed vs. Not avail0.84 (0.51, 1.39)0.57 (0.34, 0.96)0.50 (0.28, 0.89)Immediate vs. Delayed3.81 (2.26, 6.42)3.69 (2.10, 6.48)5.09 (2.81, 9.24)No dealing -refDrug dealing*Delayed vs. Not avail1.86 (1.30, 2.65)1.66 (1.18, 2.33)1.71 (1.22, 2.41)1.62 (1.14, 2.31)1.20 (0.82, 1.76)1.44 (1.00, 2.07)Immediate vs. Delayed1.47 (0.99, 2.17)1.65 (1.15, 2.37)1.49 (1.05, 2.11)1.53 (1.03, 2.28)1.86 (1.25, 2.78)1.58 (1.04, 2.38)Non-daily user - refDaily user*Delayed vs. Not avail0.66 (0.24, 1.78)1.49 (0.57, 3.84)0.88 (0.26, 2.94)1.89 (0.84, 4.28)Immediate vs. Delayed3.82 (1.43, 10.21)4.28 (1.87, 9.78)9.01 (3.18, 25.53)2.27 (1.06, 4.87)VIDUS cohortACCESS cohortDelayed vs. Not avail1.64 (0.99, 2.71)1.22 (0.76, 1.94)1.51 (0.90, 2.52)Immediate vs. Delayed0.90 (0.52, 1.54)0.94 (0.58, 1.51)0.87 (0.50, 1.49)ARYS cohortDelayed vs. Not avail1.74 (1.04, 2.93)1.01 (0.62, 1.67)1.06 (0.62, 1.81)Immediate vs. Delayed0.35 (0.20, 0.62)0.32 (0.19, 0.54)0.38 (0.21, 0.69)Immediate: immediately available (available within 10 minutes); Delayed: delayed availability (available in > 10 minutes); Not avail.: not available. ref: reference group; DTES: Downtown Eastside;^Adjusted odds ratios here are interpreted as the increased odds of availability (delayed vs. not available or immediate vs. delayed) in each calendar year.*refers to activities in the past six months. Only variables that reached statistical significance at α=0.05 were included in regression models for each substance.Drug Alcohol Depend. Author manuscript; available in PMC 2013 November 01.

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