Differences in polysubstance use patterns and drug-related outcomes between people who inject drugs receiving and not receiving opioid substitution therapies

Kim S. Betts, Gary Chan, Fairlie McIlwraith, Paul Dietze, Elizabeth Whittaker, Lucy Burns, Rosa Alati

Research output: Contribution to journalArticleResearchpeer-review

23 Citations (Scopus)


Aims: To test if polysubstance use profiles and drug-related outcomes differ between those receiving and not receiving opioid substitution therapies (OST) among people who inject drugs (PWID). Design: An annual cross-sectional, sentinel sample of PWID across Australia. Setting: Data came from 3 years (2011–13) of the Illicit Drug Reporting System (IDRS). Participants: A total of 2673 participants who injected drugs from the combined national IDRS samples of 2011 (n = 868), 2012 (n = 922) and 2013 (n = 883). Measurements: Latent class analysis (LCA) was used to summarize participants' self-reported use of 18 types of substances, with the resulting polysubstance use profiles then associated with participant experience of a number of drug-related outcomes. Findings: Polysubstance use profiles exhibiting a broad range of substance use were generally at increased risk of negative drug-related outcomes, whether or not participants were receiving OST, including thrombosis among OST receivers [odds ratio (OR) = 2.13, 95% confidence intervals (CI) = 1.09–4.17], injecting with used needles among OST receivers and non-receivers, respectively (OR = 2.78, 95% CI = 1.50–5.13; OR = 2.15, 95% CI = 1.34–3.45) and violent criminal offences among OST receivers and non-receivers, respectively (OR =2.30, 95% CI = 1.16–4.58; OR = 1.87, 95% CI = 1.14–3.07). An important exception was non-fatal overdose which was related specifically to a class of PWID who were not receiving OST and used morphine frequently (OR = 1.83, 95% CI = 1.06–3.17). Conclusion: Regardless of opioid substitution therapies usage, people who inject drugs who use a broad-range of substances experience greater levels of injecting-related injuries and poorer health outcomes and are more likely to engage in criminal activity than other groups of people who inject drugs.

Original languageEnglish
Pages (from-to)1214-1223
Number of pages10
Issue number7
Publication statusPublished - Jul 2016
Externally publishedYes


  • Drug treatment
  • latent class analysis
  • polysubstance use

Cite this