Long-term patterns of treatment use for opioid use disorder (OUD): Findings from the 18-20-year Australian Treatment Outcome Study

Jack Wilson; Katherine L Mills; Matthew Sunderland; Tom P Freeman; Madeleine Keaveny; Katherine Haasnoot; Maree Teesson; Paul S Haber; Christina Marel

doi:10.1016/j.drugpo.2023.104187

Long-term patterns of treatment use for opioid use disorder (OUD): Findings from the 18-20-year Australian Treatment Outcome Study

Int J Drug Policy. 2023 Oct:120:104187. doi: 10.1016/j.drugpo.2023.104187. Epub 2023 Sep 13.

Authors

Jack Wilson¹, Katherine L Mills², Matthew Sunderland², Tom P Freeman³, Madeleine Keaveny², Katherine Haasnoot², Maree Teesson², Paul S Haber⁴, Christina Marel²

Affiliations

¹ The Matilda Centre for Research in Mental Health and Substance Use, Level 6, Jane Foss Russell Building, G02, The University of Sydney, 2006, NSW, Australia. Electronic address: jack.wilson@sydney.edu.au.
² The Matilda Centre for Research in Mental Health and Substance Use, Level 6, Jane Foss Russell Building, G02, The University of Sydney, 2006, NSW, Australia.
³ Addiction and Mental Health Group (AIM), University of Bath, BA2 7AY, United Kingdom.
⁴ Sydney Medical School, The University of Sydney, 2006, NSW, Australia; Drug Health Services, Royal Prince Alfred Hospital, Camperdown, 2050, NSW, Australia.

PMID: 37713938
DOI: 10.1016/j.drugpo.2023.104187

Abstract

Background: Opioid-related deaths continue to increase to unprecedented rates in many regions of the world. While long-term stable treatment has been shown to reduce associated morbidity and mortality, discontinuation and numerous treatment episodes are common, limiting our understanding of the common course of treatment and associated characteristics. Therefore, using an 18-20-year follow-up of people with heroin dependence, we aimed to identify i) distinct trajectories of treatment use, ii) whether baseline characteristics predict treatment trajectory group membership, and ii) if group membership is associated with characteristics at 18-20-years post-baseline.

Methods: A total of 615 people with heroin dependence were recruited from maintenance therapy, detoxification, residential rehabilitation, or needle and syringe programs as part of the Australian Treatment Outcome Study (ATOS), a longitudinal cohort followed up on seven occasions over 18-20-years between 2001 and 2021. Of those who had complete data (n = 393), group-based trajectory modelling and a series of multinomial logistical regressions were conducted.

Results: Five trajectories of treatment use were identified: i) 'long-term low treatment' (17.2%), ii) 'rapid increase with gradual decrease' (13.9%), iii) 'late increase' (17.8%), (iv) 'long-term treatment' (27.7%), and (v) 'reduced treatment' (23.5%). Entering maintenance treatment at baseline predicted trajectory group membership, while trajectory group membership was associated with demographics and the use of heroin, methamphetamine, alcohol, and benzodiazepines at 18-20-years.

Conclusions: In one of the longest cohort studies of its kind, we characterised distinct trajectories of treatment use in people with heroin dependence over 18-20-years. Clinicians should be aware of the potential impact of demographics and substance use on long-term treatment use. Despite the well-documented benefits of long-term treatment, some patients may be able to achieve abstinence from opioids without engaging in treatment over the life-course.

Keywords: group-based trajectory modelling; longitudinal cohort study; opioid use disorder; treatment.