Opioid Prescribing after Surgery among Chronic Opioid users in Ontario: A Population-based Cohort Study

Patients who chronically use opioids may undergo surgery; it is unclear if surgery alters the trajectory of opioid consumption in these patients. We sought to determine if exposure to surgery is associated with opioid discontinuation among chronic users, and factors associated with opioid discontinuation after surgery. The study included 4,755 surgical and 14,265 matched non-surgical patients with chronic opioid use. After adjusting for patient characteristics, surgery was associated with an increased likelihood of opioid discontinuation (aHR: 1.34 95%CI: 1.27, 1.42). Among surgical patients, factors associated with a reduced odds of discontinuation included a mean preoperative opioid dose >90 morphine milligram equivalents (aOR: 0.39 95%CI:0.31, 0.49), preoperative oxycodone prescriptions (aOR: 0.74 95%CI:0.55, 0.98), and a diagnosis of chronic obstructive pulmonary disease (aOR: 0.75 95%CI: 0.64, 0.88) or dementia (aOR: 0.58 95%CI: 0.37, 0.91). Further research is needed to evaluate interventions that can influence post-operative opioid discontinuation, particularly in high risk patients.M.Sc