Poster Presentation Sydney Spinal Symposium 2025

The transportability of the OPAL trial to a primary care setting in the United States  (#5)

Harrison Hansford 1 2 , Aidan Cashin 1 2 , Hopin Lee 3 , Caitlin Jones 4 5 , Matt Jones 1 2 , Christine Lin 4 5 , James McAuley 1 2
  1. UNSW, Sydney, NSW, Australia
  2. Centre for Pain IMPACT, Neuroscience Research Australia, Sydney, Australia, Sydney, Australia
  3. IQVIA, London, United Kingdom
  4. Sydney Musculoskeletal Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
  5. The Institute for Musculoskeletal Health, Sydney Local Health District, Sydney, NSW, Australia

BACKGROUND: Opioids are frequently prescribed for acute low back pain and opioid use for back pain is highest in Australia and the USA. (1) Recent evidence from the OPAL trial (2) suggests there is no benefit of prescribing opioids (oxycodone/naloxone) for acute low back pain compared to placebo. It is unclear the extent to which the results of the OPAL trial apply to clinical-, or policy-relevant populations in the United States of America (USA). If the distribution of potential effect modifying variables differs between the trial sample and the population of interest (i.e., USA), it is plausible that the treatment effect observed in the trial would not be seen in the population. we aim to estimate the transportability of oxycodone/naloxone compared to placebo for people with acute low back pain from the OPAL trial to a USA primary care setting.

METHODS: We will use individual participant data from the OPAL trial and individual participant data at baseline from the TARGET inception cohort study, a multisite inception cohort in the USA. (3) Both trials included adults with low back pain for less than 12 weeks, without any serious underlying pathology. We will investigate the effect of a combined modified release oxycodone/naloxone compared to placebo on pain, disability, opioid misuse and quality of life. We identified common baseline covariates that may modify the treatment effect: age, sex, pain intensity, duration of pain, presence of leg pain, disability and health insurance. We will assess standardised mean differences in baseline characteristics, where a difference > 0.1 is deemed meaningful. We will estimate the conditional average treatment effect of oxycodone/naloxone in the target population (the cohort). To adjust for differences between the trial and target cohort we will weight linear regression models by the inverse probability of trial participation.

Results will be finalised before June.

  1. 1. Jayawardana S, Forman R, Johnston-Webber C, et al. Global consumption of prescription opioid analgesics between 2009-2019: A country-level observational study. eClinicalMedicine 2021; 42. DOI:10.1016/j.eclinm.2021.101198.
  2. 2. Jones CMP, Day RO, Koes BW, et al. Opioid analgesia for acute low back pain and neck pain (the OPAL trial): A randomised placebo-controlled trial. The Lancet 2023; 402: 304–12.
  3. 3. Stevans JM, Delitto A, Khoja SS, et al. Risk Factors Associated With Transition From Acute to Chronic Low Back Pain in US Patients Seeking Primary Care. JAMA Netw Open 2021; 4: e2037371.