Opioid PrEscRiptions and usage After Surgery (OPERAS): protocol for a prospective multicentre observational cohort study of opioid use after surgery

INTRODUCTION: Postoperative pain is common and frequently addressed through opioid analgesia. This practice must balance the benefits of achieving adequate pain relief against the harms of adverse effects such as opioid-induced ventilatory impairment and opioid use disorder. This student and trainee-led collaborative study aims to investigate and compare the prescription versus consumption of opioids at 7 days postdischarge after common surgical procedures and their impact on patient-reported outcomes regarding postoperative pain. METHODS AND ANALYSIS: This is a prospective multicentre observational cohort study of surgical patients in Australia, Aotearoa New Zealand and select international sites, conducted by networks of students, trainees and consultants. Consecutive adult patients undergoing common elective and emergency general, orthopaedic, gynaecological and urological surgical procedures are eligible for inclusion, with follow-up 7 days after hospital discharge. The primary outcome will be the proportion of prescribed opioids consumed by patients at 7 days postdischarge. Secondary outcomes will include patient-reported quality of life and satisfaction scores, rate of non-opioid analgesic use, rate of continuing use of opioids at follow-up, rates of opioid prescription from other sources and hospital readmissions at 7 days postdischarge for opioid related side-effects or surgery-related pain. Descriptive and multivariate analyses will be conducted to investigate factors associated with opioid requirements and prescription-consumption discrepancies. ETHICS AND DISSEMINATION: OPERAS has been approved in Australia by the Hunter New England Human Research Ethics Committee (Protocol 2021/ETH11508) and by the Southern Health and Disability Ethics Committee (2021 EXP 11199) in Aotearoa New Zealand. Results will be submitted for conference presentation and peer-reviewed publication. Centre-level data will be distributed to participating sites for internal audit. TRIAL REGISTRATION NUMBER: ANZCTR (ID: ACTRN12621001451897p)