Predictors of persistent opioid use in Australian primary care: A retrospective cohort study, 2018-2022.

Objective: To examine the predictors of persistent opioid use ('persistence') in people initiating opioids for non-cancer pain in Australian primary care.

Design: A retrospective cohort study.

Setting: Australian primary care.

Subjects: People prescribed opioid analgesics between 2018-2022, identified through the Population Level Analysis and Reporting (POLAR) database.

Methods: Persistence was defined as receiving opioid prescriptions for at least 90 days with a gap of less than 60 days between subsequent prescriptions. Multivariable logistic regression was used to examine the predictors of persistent opioid use.

Results: The sample consisted of 343,023 people initiating opioids for non-cancer pain; of these, 16,527 (4.8%) developed persistent opioid use. Predictors of persistence included older age (≥75 vs 15-44 years: Adjusted odds ratio: 1.67, 95% CI: 1.58-1.78), concessional beneficiary status (1.78, 1.71-1.86), diagnosis of substance use disorder (1.44, 1.22-1.71) and chronic pain (2.05, 1.85-2.27), initiation of opioid therapy with buprenorphine (1.95, 1.73-2.20) and long-acting opioids (2.07, 1.90-2.25), provision of higher quantity of opioids prescribed at initiation (total OME of ≥ 750mg vs < 100mg: 7.75, 6.89-8.72), provision of repeat/refill opioid prescriptions at initiation (2.94, 2.77-3.12), and prescription of gabapentinoids (1.59, 1.50-1.68), benzodiazepines (1.43, 1.38-1.50) and z-drugs (e.g., zopiclone, zolpidem; 1.61, 1.46-1.78).

Conclusions: These findings add to the limited evidence of individual-level factors associated with persistent opioid use. Further research is needed to understand the clinical outcomes of persistent opioid use in people with these risk factors to support the safe and effective prescribing of opioids.