Painfully Obvious? Non-Operative Drivers of Post-Operative Pain and Opioid Exposure in a Predominantly Emergency Surgical Cohort: A Multicentre Observational Study Identifying Non-Operative, Perioperative Pain Correlates.

Introduction: There are many non-operative factors (patient specific and management strategies) that are ubiquitous across all surgeries, which may influence perioperative pain. Recognition of these factors and their association with pain and analgesia requirements could provide avenues for improved perioperative care.

Methods: All consecutive surgical patients admitted to six Australian tertiary hospitals (2017-2024) were included. The primary outcome was postoperative pain score (0 = no pain to 10 = unbearable pain). Additional outcomes included "Pain Crisis", quantity of postoperative and discharge analgesia. Pain scores were calculated using the median scores in the 5 days postoperatively. Postoperative analgesia was quantified by total morphine milligram equivalents (MME) in the 5 days postoperatively and discharge analgesia as MME provided on the discharge prescription. Multivariable binary logistic and linear regression models, with backward elimination, were employed with clinical characteristics and non-operative management factors included as predictors.

Results: A total of 37,278 patients were included. Of these, 92% were unplanned emergency procedures. Psychological factors, such as depression and anxiety, significantly influenced perioperative pain and opioid use. An increase in socio-economic status was associated with less postoperative analgesia but more discharge analgesia. Older patients generally experienced less pain and required fewer opioids. Contrastingly, increased frailty correlated with higher opioid usage. Patients speaking English as a primary language reported more postoperative pain, without higher opioid use. Patients who did not identify as a First Nations Australian received 30% more opioids on discharge, despite no relationship with pain.

Discussion/conclusion: An integrated, anticipatory, patient-centric approach to perioperative pain and analgesia that considers not only the surgical factors but also the individual's psychological and socio-economic context is required.