Mortality in the SuperMIX cohort of people who inject drugs in Melbourne, Australia: A prospective observational study

Penelope L Hill, Mark Stoové, Paul A. Agius, Lisa Maher, Matt Hickman, Sione Crawford, Paul Dietze

Research output: Contribution to journalArticle (Academic Journal)peer-review

3 Citations (Scopus)
61 Downloads (Pure)

Abstract

Aims
To measure mortality rates and factors associated with mortality risk among participants in the SuperMIX study, a prospective cohort study of people who inject drugs.

Design
A prospective observational study using self-reported behavioural and linked mortality data.

Setting
Melbourne, Australia.

Participants/cases
A total of 1209 people who inject drugs (67% male) followed-up between 2008 and 2019 for 6913 person-years (PY).

Measurements
We linked participant identifiers from SuperMIX to the Australian National Death Index and estimated all-cause and drug-related mortality rates and standardized mortality ratios (SMRs). We used Cox regression to examine associations between mortality and fixed and time-varying socio-demographic, alcohol and other drug use and health service-related exposures.

Findings
Between 2008 and 2019 there were 76 deaths in the SuperMIX cohort. Of those with a known cause of death (n = 68), 35 (51%) were drug-related, yielding an all-cause mortality rate of 1.1 per 100 PY [95% confidence interval (CI) = 0.88–1.37] with an estimated SMR of 16.64 (95% CI = 13.29–20.83) and overall accidental drug-induced mortality rate of 0.5 per 100 PY (95% CI = 0.36–0.71). Reports of recent use of ambulance services [adjusted hazard ratio (aHR) = 3.77, 95% CI =1.78–7.97] and four or more incarcerations (aHR = 2.78, 95% CI = 1.55–4.99) were associated with increased mortality risk.

Conclusions
In Melbourne, Australia, mortality among people who inject drugs appears to be positively associated with recent ambulance attendance and experience of incarceration.
Original languageEnglish
Pages (from-to)3091-3098
Number of pages8
JournalAddiction
Volume117
Issue number12
Early online date16 Jun 2022
DOIs
Publication statusE-pub ahead of print - 16 Jun 2022

Bibliographical note

Funding Information:
P.D. has received an investigator‐driven grant from Gilead Sciences for unrelated work on hepatitis C and an untied educational grant from Reckitt Benckiser for unrelated work on the introduction of buprenorphine–naloxone into Australia. M.S. has received investigator‐initiated funding from Gilead Sciences, AbbVie and Bristol Myers Squibb for research unrelated to this work. M.H. has received in the last 3 years unrestricted honoraria/speaker fees from MSD and Gilead.

Funding Information:
The MIX/SuperMIX study is supported by The Colonial Foundation Trust and the National Health and Medical Research Council (545891 and 1126090). P.L.H. is the recipient of a NHMRC Postgraduate Scholarship and P.D., M.S. and L.M. are recipients of NHMRC Senior Research Fellowships. M.H. is NIHR Senior Investigator. The authors gratefully acknowledge the contribution to this work of the Victorian Operational Infrastructure Support Program's support of the Burnet Institute. The funding bodies played no role in the study design, data analysis or preparation of the manuscript for publication. M.H. acknowledges support from NIHR HPRU in Behavioural Science and Evaluation. The authors wish to thank the participants of the SuperMIX study, together with the staff of the community-based organizations who assisted in recruitment. Thank you to the members of the SuperMIX study team who assisted with participant recruitment, follow-up and interviewing. We would also like to acknowledge the support of the staff at the AIFS and AIHW who assisted with linked data access. Open access publishing facilitated by Monash University, as part of the Wiley - Monash University agreement via the Council of Australian University Librarians.

Funding Information:
The MIX/SuperMIX study is supported by The Colonial Foundation Trust and the National Health and Medical Research Council (545891 and 1126090). P.L.H. is the recipient of a NHMRC Postgraduate Scholarship and P.D., M.S. and L.M. are recipients of NHMRC Senior Research Fellowships. M.H. is NIHR Senior Investigator. The authors gratefully acknowledge the contribution to this work of the Victorian Operational Infrastructure Support Program's support of the Burnet Institute. The funding bodies played no role in the study design, data analysis or preparation of the manuscript for publication. M.H. acknowledges support from NIHR HPRU in Behavioural Science and Evaluation. The authors wish to thank the participants of the SuperMIX study, together with the staff of the community‐based organizations who assisted in recruitment. Thank you to the members of the SuperMIX study team who assisted with participant recruitment, follow‐up and interviewing. We would also like to acknowledge the support of the staff at the AIFS and AIHW who assisted with linked data access. Open access publishing facilitated by Monash University, as part of the Wiley ‐ Monash University agreement via the Council of Australian University Librarians.

Publisher Copyright:
© 2022 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

Keywords

  • ambulance
  • drug-related deaths
  • injecting drug use
  • mortality
  • opioids
  • people who inject drugs

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