Persistent opioid use after hospital admission due to trauma: a population-based cohort study

Persistent opioid use (POU) is a common marker of harm related to opioid use after trauma. This study determined the incidence and risk factors for POU after hospitalisation due to trauma in New Zealand, among opioid-naïve patients. This was a population-based, retrospective cohort study, using linked data, involving all trauma patients of any age admitted to all NZ hospitals between 2007 and 2019. We included all patients who received opioids after discharge and were considered opioid naïve, defined as not having received opioids or not having a prior diagnosis of opioid-use disorder up to 365 days preceding the discharge date. The primary outcome was the incidence of POU defined as opioid use after discharge between 91 and 365 days. We used a multivariable logistic regression to identify independent risk factors for POU. A total of 177,200 patients were included in this study. Of these, 15.3% (n = 27,060) developed POU based on criteria used for the primary analysis, with sensitivity analyses showing POU incidence ranging from 14.3% to 0.8%. The opioid exposure risk factors associated with POU included switching between different opioids (adjusted odds ratio [aOR] 2.62; 95% confidence interval [CI] 2.51-2.73), prescribed multiple opioids (vs codeine, aOR 1.44; 95% CI 1.37-1.53), slow-release opioid formulations (aOR 1.32; 95% CI 1.26-1.39), and dispensed higher total doses of on the initial discharge prescription (aOR 1.26; 95% CI 1.20-1.33). Overall, 1 in 7 opioid-naïve patients who were exposed to opioids after trauma developed POU. Our findings highlight clinicians should be aware of these factors when continuing opioids on discharge.