Correlation between postoperative pain trajectories and recovery after day surgery: a protocol for a prospective cohort study.

We hypothesise that distinct postoperative pain trajectories are significantly associated with postoperative recovery outcomes. To test this, we will systematically investigate the dynamic trajectories of postoperative pain, identify influencing factors and explore the relationship between pain trajectory categories and recovery within 1 month postoperatively. We plan to enrol 1000 day surgery patients. The primary outcome measure will be the recovery status at 1 month postoperatively, assessed using the Recovery Quality of Life Scale-15. The secondary outcome measures will be the patients' subjective recovery ratings, satisfaction scores and pain interference with daily life scores. To capture pain progression, assessments will be conducted at four time points (days 1, 3, 7 and 30) using the Brief Pain Inventory. Latent class growth analysis will identify distinct pain trajectory classes, and their association with postoperative recovery will be examined. Generalised linear mixed models and least absolute shrinkage and selection operator regression will be used to identify risk factors for high-risk pain trajectories. This study has been approved by the Sichuan Provincial Medical Ethics Committee (ethical review No. 749, 2024). Findings will be disseminated to participants, funders, the research community and the public to ensure transparency and accessibility. ChiCTR2500095991.