Supervised injection facility use and all-cause mortality among people who inject drugs in Vancouver, Canada: A cohort study

English version

Autoři: Mary Clare Kennedy ^aff001; Kanna Hayashi ^aff001; M-J Milloy ^aff001; Evan Wood ^aff001; Thomas Kerr ^aff001
Působiště autorů: British Columbia Centre on Substance Use, St. Paul’s Hospital, Vancouver, British Columbia, Canada ^aff001; Department of Medicine, University of British Columbia, St. Paul’s Hospital, Vancouver, British Columbia, Canada ^aff002; Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada ^aff003
Vyšlo v časopise: Supervised injection facility use and all-cause mortality among people who inject drugs in Vancouver, Canada: A cohort study. PLoS Med 16(11): e32767. doi:10.1371/journal.pmed.1002964
Kategorie: Research Article
doi: https://doi.org/10.1371/journal.pmed.1002964

Souhrn

Background

People who inject drugs (PWID) experience elevated rates of premature mortality. Although previous studies have demonstrated the role of supervised injection facilities (SIFs) in reducing various harms associated with injection drug use, including accidental overdose death, the possible impact of SIF use on all-cause mortality is unknown. Therefore, we examined the relationship between frequent SIF use and all-cause mortality among PWID in Vancouver, Canada.

Methods and findings

Data were derived from 2 prospective cohort studies of PWID in Vancouver, Canada, between December 2006 and June 2017. Every 6 months, participants completed questionnaires that elicited information regarding sociodemographic characteristics, substance use patterns, social-structural exposures, and use of health services including SIFs. These data were confidentially linked to the provincial vital statistics database to ascertain mortality rates and causes of death. We used multivariable extended Cox regression analyses to estimate the independent association between frequent (i.e., at least weekly) SIF use and all-cause mortality. Of 811 participants, 278 (34.3%) were women, and the median age was 39 years (IQR 33–46) at baseline. In total, 432 (53.3%) participants reported frequent SIF use at baseline, and 379 (46.7%) did not. At baseline, frequent SIF users were on average younger than nonfrequent users, and a higher proportion of frequent SIF users than nonfrequent users were unstably housed, resided in the Downtown Eastside neighbourhood, injected in public, had a recent non-fatal overdose, used prescription opioids at least daily, injected heroin at least daily, injected cocaine at least daily, and injected crystal methamphetamine at least daily. A lower proportion of frequent SIF users than nonfrequent users were HIV positive and enrolled in addiction treatment at baseline. The median duration of follow-up among study participants was 72 months (IQR 24–123). In total, 112 participants (13.8%) died during the study period, yielding a crude mortality rate of 22.7 (95% CI 18.7–27.4) deaths per 1,000 person-years. The median years of potential life lost per death was 34 (IQR 27–42) years. In a time-updated multivariable model, frequent SIF use was inversely associated with risk of all-cause mortality after adjusting for potential confounders, including age, sex, HIV seropositivity, unstable housing, at least daily cocaine injection, public injection, incarceration, enrolment in addiction treatment, and calendar year of interview (adjusted hazard ratio 0.46, 95% CI 0.26–0.80, p = 0.006). The main study limitations are the limited generalizability of findings due to non-random sampling, the potential for reporting biases due to reliance on some self-reported information, and the possibility that residual confounding influenced findings.

Conclusions

We observed a high burden of premature mortality among a community-recruited cohort of PWID. Frequent SIF use was associated with a lower risk of death, independent of relevant confounders. These findings support efforts to enhance access to SIFs as a strategy to reduce mortality among PWID. Further analyses of individual-level data are needed to determine estimates of, and potential causal pathways underlying, associations between SIF use and specific causes of death.

Klíčová slova:

Canada – Cocaine – Crystals – Death rates – Drug users – Heroin – Opioids

Zdroje

1. Mathers BM, Degenhardt L, Bucello C, Lemon J, Wiessing L, Hickman M. Mortality among people who inject drugs: a systematic review and meta-analysis. Bull World Health Organ. 2013;91(2):102–23. doi: 10.2471/BLT.12.108282 23554523

2. Health Canada. National report: apparent opioid-related deaths in Canada (September 2019). Ottawa: Government of Canada; 2019 [cited 2019 Oct 21]. Available from: https://health-infobase.canada.ca/datalab/national-surveillance-opioid-mortality.html.

3. National Institute on Drug Abuse. Overdose death rates. North Bethesda (MD): National Institute on Drug Abuse; 2019 [cited 2019 May 29]. Available from: https://www.drugabuse.gov/related-topics/trends-statistics/overdose-death-rates.

4. Statistics Canada. Changes in life expectancy by selected causes of death, 2017. Ottawa: Statistics Canada; 2019 [cited 2019 Jun 4]. Available from: https://www150.statcan.gc.ca/n1/daily-quotidien/190530/dq190530d-eng.htm.

5. Darke S, Degenhardt L, Mattick R. Mortality amongst illicit drug users: epidemiology, causes and intervention. Cambridge: Cambridge University Press; 2006. 145 p.

6. Hayashi K, Dong H, Marshall BDL, Milloy M-J, Montaner JSG, Wood E, et al. Sex-based differences in rates, causes, and predictors of death among injection drug users in Vancouver, Canada. Am J Epidemiol. 2016;183(6):544–52. doi: 10.1093/aje/kwv207 26865265

7. Copeland L, Budd J, Robertson JR, Elton RA. Changing patterns in causes of death in a cohort of injecting drug users, 1980–2001. Arch Intern Med. 2004;164(11):1214. doi: 10.1001/archinte.164.11.1214 15197047

8. Miller CL, Kerr T, Strathdee SA, Li K, Wood E. Factors associated with premature mortality among young injection drug users in Vancouver. Harm Reduct J. 2007;4:1. doi: 10.1186/1477-7517-4-1 17201933

9. Vanichseni S, Martin M, Suntharasamai P, Sangkum U, Mock PA, Gvetadze RJ, et al. High mortality among non-HIV-infected people who inject drugs in Bangkok, Thailand, 2005–2012. Am J Public Health. 2015;105(6):1136–41. doi: 10.2105/AJPH.2014.302473 25880964

10. European Monitoring Centre for Drugs and Drug Addiction. Drug consumption rooms: an overview of provision and evidence. Lisbon: European Monitoring Centre for Drugs and Drug Addiction; 2018 [cited 2019 Jun 8]. Available from: http://www.emcdda.europa.eu/topics/pods/drug-consumption-rooms.

11. Kennedy MC, Karamouzian M, Kerr T. Public health and public order outcomes associated with supervised drug consumption facilities: a systematic review. Curr HIV/AIDS Rep. 2017;14(5):161–83. doi: 10.1007/s11904-017-0363-y 28875422

12. Health Canada. Supervised consumption sites: status of applications. Ottawa: Government of Canada; 2019 [cited 2019 Jun 1]. Available from: https://www.canada.ca/en/health-canada/services/substance-abuse/supervised-consumption-sites/status-application.html.

13. Irvine MA, Kuo M, Buxton J, Balshaw R, Otterstatter M, Macdougall L, et al. Modelling the combined impact of interventions in averting deaths during a synthetic-opioid overdose epidemic. Addiction. 2019;114(9): 1602–13. doi: 10.1111/add.14664 31166621

14. Perkel C. Ontario announces 15 overdose prevention sites across the province. National Post. 2019 Mar 29 [cited 2019 Jun 14]. Available from: https://nationalpost.com/pmn/news-pmn/canada-news-pmn/ontario-announces-15-overdose-prevention-sites-across-the-province.

15. Belackova V, Salmon AM, Schatz E, Jauncey M. Drug consumption rooms (DCRs) as a setting to address hepatitis C—findings from an international online survey. Hepatol Med Policy. 2018;3:9. doi: 10.1186/s41124-018-0035-6 30288332

16. Kerr T, Mitra S, Kennedy MC, McNeil R. Supervised injection facilities in Canada: past, present, and future. Harm Reduct J. 2017;14:28. doi: 10.1186/s12954-017-0154-1 28521829

17. Vancouver Coastal Health. Overdose prevention & response. Vancouver: Vancouver Coastal Health; 2019 [cited 2019 May 20]. Available from: http://www.vch.ca/public-health/harm-reduction/overdose-prevention-response.

18. Davidson PJ, Lopez AM, Kral AH. Using drugs in un/safe spaces: impact of perceived illegality on an underground supervised injecting facility in the United States. Int J Drug Policy. 2018;53:37–44. doi: 10.1016/j.drugpo.2017.12.005 29278831

19. Potier C, Laprévote V, Dubois-Arber F, Cottencin O, Rolland B. Supervised injection services: what has been demonstrated? A systematic literature review. Drug Alcohol Depend. 2014;145:48–68. doi: 10.1016/j.drugalcdep.2014.10.012 25456324

20. McNeil R, Small W. ‘Safer environment interventions’: a qualitative synthesis of the experiences and perceptions of people who inject drugs. Soc Sci Med. 2014;106:151–8. doi: 10.1016/j.socscimed.2014.01.051 24561777

21. Bravo MJ, Royuela L, De la Fuente L, Brugal MT, Barrio G, Domingo-Salvany A, et al. Use of supervised injection facilities and injection risk behaviours among young drug injectors. Addiction. 2009;104(4):614–9. doi: 10.1111/j.1360-0443.2008.02474.x 19215603

22. Kimber J, MacDonald M, van Beek I, Kaldor J, Weatherburn D, Lapsley H, et al. The Sydney Medically Supervised Injecting Centre: client characteristics and predictors of frequent attendance during the first 12 months of operation. J Drug Issues. 2003;33(3):639–48.

23. Scherbaum N, Specka M, Bombeck J, Marrziniak B. Drug consumption facility as part of a primary health care centre for problem drug users—which clients are attracted? Int J Drug Policy. 2009;20(5):447–9. doi: 10.1016/j.drugpo.2009.01.001 19269803

24. Kennedy MC, Klassen DC, Dong H, Milloy M-JS, Hayashi K, Kerr TH. Supervised injection facility utilization patterns: a prospective cohort study in Vancouver, Canada. Am J Prev Med. 2019;57(3):330–7. doi: 10.1016/j.amepre.2019.04.024 31377091

25. Wood E, Tyndall MW, Qui Z, Zhang R, Montaner JSG, Kerr T. Service uptake and characteristics of injection drug users utilizing North America’s first medically supervised safer injecting facility. Am J Public Health. 2006;96(5):770–3. doi: 10.2105/AJPH.2004.057828 16571703

26. Wood E, Tyndall MW, Li K, Lloyd-Smith E, Small W, Montaner JSG, et al. Do supervised injecting facilities attract higher-risk injection drug users? Am J Prev Med. 2005;29(2):126–30. doi: 10.1016/j.amepre.2005.04.011 16005809

27. Strathdee SA, Galai N, Safaiean M, Celentano DD, Vlahov D, Johnson L, et al. Sex differences in risk factors for HIV seroconversion among injection drug users: a 10-year perspective. Arch Intern Med. 2001;161(10):1281. doi: 10.1001/archinte.161.10.1281 11371255

28. Tyndall MW, Currie S, Spittal P, Li K, Wood E, O’Shaughnessy MV, et al. Intensive injection cocaine use as the primary risk factor in the Vancouver HIV-1 epidemic. AIDS. 2003;17(6):887. doi: 10.1097/00002030-200304110-00014 12660536

29. Piggott DA, Muzaale AD, Mehta SH, Brown TT, Patel KV, Leng SX, et al. Frailty, HIV infection, and mortality in an aging cohort of injection drug users. PLoS ONE. 2013;8(1):e54910. doi: 10.1371/journal.pone.0054910 23382997

30. Linton SL, Celentano DD, Kirk GD, Mehta SH. The longitudinal association between homelessness, injection drug use, and injection-related risk behavior among persons with a history of injection drug use in Baltimore, MD. Drug Alcohol Depend. 2013;132(3):457–65. doi: 10.1016/j.drugalcdep.2013.03.009 23578590

31. Galea S, Vlahov D. Social determinants and the health of drug users: socioeconomic status, homelessness, and incarceration. Public Health Rep. 2002;117:S135–45. 12435837

32. Kerr T, Tyndall M, Li K, Montaner J, Wood E. Safer injection facility use and syringe sharing in injection drug users. Lancet. 2005;366(9482):316–8. doi: 10.1016/S0140-6736(05)66475-6 16039335

33. Wood E, Tyndall MW, Zhang R, Stoltz J -A, Lai C, Montaner JSG, et al. Attendance at supervised injecting facilities and use of detoxification services. N Engl J Med. 2006;354(23):2512–4. doi: 10.1056/NEJMc052939 16760459

34. Wood E, Tyndall MW, Zhang R, Montaner JSG, Kerr T. Rate of detoxification service use and its impact among a cohort of supervised injecting facility users. Addiction. 2007;102(6):916–9. doi: 10.1111/j.1360-0443.2007.01818.x 17523986

35. DeBeck K, Kerr T, Bird L, Zhang R, Marsh D, Tyndall M, et al. Injection drug use cessation and use of North America’s first medically supervised safer injecting facility. Drug Alcohol Depend. 2011;113(2–3):172–6. doi: 10.1016/j.drugalcdep.2010.07.023 20800976

36. Gaddis A, Kennedy MC, Nosova E, Milloy M-J, Hayashi K, Wood E, et al. Use of on-site detoxification services co-located with a supervised injection facility. J Subst Abuse Treat. 2017;82:1–6. doi: 10.1016/j.jsat.2017.08.003 29021106

37. Lloyd-Smith E, Wood E, Zhang R, Tyndall MW, Sheps S, Montaner JS, et al. Determinants of hospitalization for a cutaneous injection-related infection among injection drug users: a cohort study. BMC Public Health. 2010;10(1):327.

38. Lloyd-Smith E, Tyndall M, Zhang R, Grafstein E, Sheps S, Wood E, et al. Determinants of cutaneous injection-related infections among injection drug users at an emergency department. Open Infect Dis J. 2012;6:5–11.

39. Kimber J, Mattick RP, Kaldor J, Van Beek I, Gilmour S, Rance J. Process and predictors of drug treatment referral and referral uptake at the Sydney Medically Supervised Injecting Centre. Drug Alcohol Rev. 2008;27(6):602–12. doi: 10.1080/09595230801995668 19378444

40. van der Poel A, Barendregt C, van de Mheen D. Drug consumption rooms in Rotterdam: an explorative description. Eur Addict Res. 2003;9:94–100. doi: 10.1159/000068807 12644736

41. Zurhold H, Degkwitz P, Verthein U, Haasen C. Drug consumption rooms in Hamburg, Germany: evaluation of the effects on harm reduction and the reduction of public nuisance. J Drug Issues. 2003;33(3):663–88.

42. Toth EC, Tegner J, Lauridsen S, Kappel N. A cross-sectional national survey assessing self-reported drug intake behavior, contact with the primary sector and drug treatment among service users of Danish drug consumption rooms. Harm Reduct J. 2016;13:27. doi: 10.1186/s12954-016-0115-0 27717366

43. Kinnard EN, Howe CJ, Kerr T, Skjødt Hass V, Marshall BDL. Self-reported changes in drug use behaviors and syringe disposal methods following the opening of a supervised injecting facility in Copenhagen, Denmark. Harm Reduct J. 2014;11:29. doi: 10.1186/1477-7517-11-29 25352296

44. Marshall BDL, Milloy M-J, Wood E, Montaner JS, Kerr T. Reduction in overdose mortality after the opening of North America’s first medically supervised safer injecting facility: a retrospective population-based study. Lancet. 2011;377(9775):1429–37. doi: 10.1016/S0140-6736(10)62353-7 21497898

45. Salmon AM, Van Beek I, Amin J, Kaldor J, Maher L. The impact of a supervised injecting facility on ambulance call-outs in Sydney, Australia. Addiction. 2010;105(4):676–83. doi: 10.1111/j.1360-0443.2009.02837.x 20148794

46. National Centre in HIV Epidemiology and Clinical Research. Sydney Medically Supervised Injecting Centre evaluation report no. 4: evaluation of service operation and overdose-related events. Sydney: University of New South Wales; 2007 [cited 2019 Oct 21]. Available from: https://kirby.unsw.edu.au/sites/default/files/kirby/report/EvalRep4SMSIC.pdf.

47. Poschadel S, Höger R, Schnitzler J, Schreckenberger J. Evaluation der Arbeit der Drogenkonsumräume in der Bundesrepublik Deutschland: Endbericht im Auftrag des Bundesministeriums für Gesundheit, das Bundesministerium für Gesundheit und Soziale Sicherung. Band 149. Baden-Baden: Nomos Verlagsgesellschaft; 2003.

48. Milloy M-J, Kerr T, Tyndall M, Montaner J, Wood E. Estimated drug overdose deaths averted by North America’s first medically-supervised safer injection facility. PLoS ONE. 2008;3(10):e3351. doi: 10.1371/journal.pone.0003351 18839040

49. Hedrich D. European report on drug consumption rooms. Lisbon: European Monitoring Centre for Drugs and Drug Addiction; 2004 [cited 2019 Oct 21]. Available from: http://www.emcdda.europa.eu/system/files/publications/339/Consumption_rooms_101741.pdf.

50. Strathdee SA, Palepu A, Cornelisse PGA, Yip B, O’Shaughnessy MV, Montaner JSG, et al. Barriers to use of free antiretroviral therapy in injection drug users. JAMA. 1998;280(6):547–9. doi: 10.1001/jama.280.6.547 9707146

51. Wood E, Tyndall MW, Spittal PM, Li K, Kerr T, Hogg RS, et al. Unsafe injection practices in a cohort of injection drug users in Vancouver: could safer injecting rooms help? Can Med Assoc J. 2001;165(4):405–10.

52. Wood E, Lloyd-Smith E, Li K, Strathdee SA, Small W, Tyndall MW, et al. Frequent needle exchange use and HIV incidence in Vancouver, Canada. Am J Med. 2007;120(2):172–9. doi: 10.1016/j.amjmed.2006.02.030 17275459

53. Psaty BM, Siscovick DS. Minimizing bias due to confounding by indication in comparative effectiveness research: the importance of restriction. JAMA. 2010;304(8):897–8. doi: 10.1001/jama.2010.1205 20736474

54. Rothman KJ, Gallacher JE, Hatch EE. Why representativeness should be avoided. Int J Epidemiol. 2013;42(4):1012–4. doi: 10.1093/ije/dys223 24062287

55. McGrath LJ, Ellis AR, Brookhart MA. Controlling time-dependent confounding by health status and frailty: restriction versus statistical adjustment. Am J Epidemiol. 2015;182(1):17–25. doi: 10.1093/aje/kwu485 25868551

56. Secrest MH, Platt RW, Dormuth CR, Chateau D, Targownik L, Nie R, et al. Extreme restriction design as a method for reducing confounding by indication in pharmacoepidemiologic research. Pharmacoepidemiol Drug Saf. 2019 Jan 9. doi: 10.1002/pds.4708 30628152

57. National Institute on Alcohol Abuse and Alcoholism. Rethinking drinking: alcohol and your health. NIH Publication No. 15–3770. Bethesda (MD): National Institute on Alcohol Abuse and Alcoholism; 2016 [cited 2019 May 24]. Available from: https://www.niaaa.nih.gov/sites/default/files/publications/Rethinking_Drinking.pdf.

58. Zivanovic R, Milloy M, Hayashi K, Dong H, Sutherland C, Kerr T, et al. Impact of unstable housing on all-cause mortality among persons who inject drugs. BMC Public Health. 2015;15:106. doi: 10.1186/s12889-015-1479-x 25884182

59. Hayden A, Hayashi K, Dong H, Milloy M-J, Kerr T, Montaner JS, et al. The impact of drug use patterns on mortality among polysubstance users in a Canadian setting: a prospective cohort study. BMC Public Health. 2014;14:1153. doi: 10.1186/1471-2458-14-1153 25377274

60. Aragón TJ, Lichtensztajn DY, Katcher BS, Reiter R, Katz MH. Calculating expected years of life lost for assessing local ethnic disparities in causes of premature death. BMC Public Health. 2008;8:116. doi: 10.1186/1471-2458-8-116 18402698

61. Milloy M-J, Wood E, Reading C, Kane D, Montaner J, Kerr T. Elevated overdose mortality rates among First Nations individuals in a Canadian setting: a population-based analysis. Addiction. 2010;105(11):1962–70. doi: 10.1111/j.1360-0443.2010.03077.x 20825372

62. Lloyd-Smith E, Brodkin E, Wood E, Kerr T, Tyndall MW, Montaner JS, et al. Impact of HAART and injection drug use on life expectancy of two HIV-positive cohorts in British Columbia. AIDS. 2006;20(3):445. doi: 10.1097/01.aids.0000206508.32030.92 16439879

63. Stoltz J-A, Wood E, Small W, Li K, Tyndall M, Montaner J, et al. Changes in injecting practices associated with the use of a medically supervised safer injection facility. J Public Health. 2007;29(1):35–9.

64. Sordo L, Barrio G, Bravo MJ, Indave BI, Degenhardt L, Wiessing L, et al. Mortality risk during and after opioid substitution treatment: systematic review and meta-analysis of cohort studies. BMJ. 2017;357:j1550. doi: 10.1136/bmj.j1550 28446428

65. Scott CK, Dennis ML, Laudet A, Funk RR, Simeone RS. Surviving drug addiction: the effect of treatment and abstinence on mortality. Am J Public Health. 2011;101(4):737–44. doi: 10.2105/AJPH.2010.197038 21330586

66. Bahji A, Cheng B, Gray S, Stuart H. Reduction in mortality risk with opioid agonist therapy: a systematic review and meta‐analysis. Acta Psychiatr Scand. 2019;140(4):313–39. doi: 10.1111/acps.13088 31419306

67. Tyndall MW, Kerr T, Zhang R, King E, Montaner JG, Wood E. Attendance, drug use patterns, and referrals made from North America’s first supervised injection facility. Drug Alcohol Depend. 2006;83(3):193–8. doi: 10.1016/j.drugalcdep.2005.11.011 16356659

68. Karamouzian M, Dohoo C, Forsting S, McNeil R, Kerr T, Lysyshyn M. Evaluation of a fentanyl drug checking service for clients of a supervised injection facility, Vancouver, Canada. Harm Reduct J. 2018;15:46. doi: 10.1186/s12954-018-0252-8 30200991

69. McNeil R, Dilley LB, Guirguis-Younger M, Hwang SW, Small W. Impact of supervised drug consumption services on access to and engagement with care at a palliative and supportive care facility for people living with HIV/AIDS: a qualitative study. J Int AIDS Soc. 2014;17:18855. doi: 10.7448/IAS.17.1.18855 24629844

70. Small W, Wood E, Lloyd-Smith E, Tyndall M, Kerr T. Accessing care for injection-related infections through a medically supervised injecting facility: a qualitative study. Drug Alcohol Depend. 2008;98(1–2):159–62. doi: 10.1016/j.drugalcdep.2008.05.014 18650034

71. Lloyd-Smith E, Wood E, Zhang R, Tyndall MW, Montaner JS, Kerr T. Determinants of cutaneous injection-related infection care at a supervised injecting facility. Ann Epidemiol. 2009;19(6):404–9. doi: 10.1016/j.annepidem.2009.03.007 19364660

72. Small W, Van Borek N, Fairbairn N, Wood E, Kerr T. Access to health and social services for IDU: the impact of a medically supervised injection facility. Drug Alcohol Rev. 2009;28(4):341–6. doi: 10.1111/j.1465-3362.2009.00025.x 19594786

73. Petrar S, Kerr T, Tyndall MW, Zhang R, Montaner JSG, Wood E. Injection drug users’ perceptions regarding use of a medically supervised safer injecting facility. Addict Behav. 2007;32(5):1088–93. doi: 10.1016/j.addbeh.2006.07.013 16930849

74. Small W, Shoveller J, Moore D, Tyndall M, Wood E, Kerr T. Injection drug users’ access to a supervised injection facility in Vancouver, Canada: the influence of operating policies and local drug culture. Qual Health Res. 2011;21(6):743–56. doi: 10.1177/1049732311400919 21378259

75. Wood E, Tyndall MW, Montaner JS, Kerr T. Summary of findings from the evaluation of a pilot medically supervised safer injecting facility. Can Med Assoc J. 2006;175(11):1399–404.

76. Fairbairn N, Small W, Van Borek N, Wood E, Kerr T. Social structural factors that shape assisted injecting practices among injection drug users in Vancouver, Canada: a qualitative study. Harm Reduct J. 2010;7:20. doi: 10.1186/1477-7517-7-20 20807442

77. Gagnon M. It’s time to allow assisted injection in supervised injection sites. CMAJ. 2017;189(34):E1083–4. doi: 10.1503/cmaj.170659 28847779

78. Ti L, Dong H, Kerr T, Turje R, Parashar S, Min J, et al. The effect of engagement in an HIV/AIDS integrated health programme on plasma HIV-1 RNA suppression among HIV-positive people who use illicit drugs: a marginal structural modelling analysis. HIV Med. 2017;18(8):580–6. doi: 10.1111/hiv.12493 28317290

79. Collins AB, Parashar S, Hogg RS, Fernando S, Worthington C, McDougall P, et al. Integrated HIV care and service engagement among people living with HIV who use drugs in a setting with a community-wide treatment as prevention initiative: a qualitative study in Vancouver, Canada. J Int AIDS Soc. 2017;20(1):21407. doi: 10.7448/IAS.20.1.21407 28426185

80. Wood W. Distributing “take home” naloxone via Sydney medically supervised injecting centre: where to from here? Drug Alcohol Rev. 2015;34(S1):67.

81. Wilson D. Toxicology backlog delaying drug overdose test results. CBC News. 2017 Mar 14 [cited 2019 May 23]; Available from: https://www.cbc.ca/news/canada/british-columbia/drugs-overdose-fentanyl-toxicology-backlog-1.4024621.

82. VanderWeele TJ, Ding P. Sensitivity analysis in observational research: introducing the e-value. Ann Intern Med. 2017;167(4):268. doi: 10.7326/M16-2607 28693043

83. Collins AB, Boyd J, Mayer S, Fowler A, Kennedy MC, Bluthenthal RN, et al. Policing space in the overdose crisis: a rapid ethnographic study of the impact of law enforcement practices on the effectiveness of overdose prevention sites. Int J Drug Policy. 2019 Sep 6. doi: 10.1016/j.drugpo.2019.08.002 31542327

84. McNeil R, Shannon K, Shaver L, Kerr T, Small W. Negotiating place and gendered violence in Canada’s largest open drug scene. Int J Drug Policy. 2014;25(3):608–15. doi: 10.1016/j.drugpo.2013.11.006 24332972

85. McNeil R, Cooper H, Small W, Kerr T. Area restrictions, risk, harm, and health care access among people who use drugs in Vancouver, Canada: a spatially oriented qualitative study. Health Place. 2015;35:70–8. doi: 10.1016/j.healthplace.2015.07.006 26241893