Comparing opioid types in the persistence of opioid use following surgical admission: a study protocol for a retrospective observational linkage study comparing tapentadol and oxycodone in Australia

Introduction: Each year, an estimated two million Australians commence opioids, with 50 000 developing longer-term (persistent) opioid use. An estimated 3%-10% of opioid-naïve patients prescribed opioids following surgery develop persistent opioid use. This study will compare rates of persistent opioid use between two commonly used postoperative opioids, oxycodone and tapentadol, to understand if initial postoperative opioid type is important in determining longer-term outcomes.

Methods and analysis: A retrospective data linkage study that analyses administrative data from hospital and community pharmacies. Data will be obtained from at least four pharmacies that service large hospitals with comparable supplies of oxycodone and tapentadol. The study will include at least 6000 patients who have been dispensed a supply of oxycodone or tapentadol to take home following their discharge from a surgical ward. The primary outcome measure will be persistent opioid use at 3 months postdischarge for opioid naïve people who receive either immediate release tapentadol or immediate release oxycodone. Hierarchical logistic regression models will be used to predict persistent opioid use, controlling for covariates including comorbidities.

Ethics and dissemination: Ethics approval has been obtained through the Monash University Human Research Ethics Committee (29977). We will present project findings in a peer-reviewed journal article, in accordance with the REporting of studies Conducted using Observational Routinely-collected health Data statement.