Postoperative Pain Trajectories, Predictors of Severe Pain, and Satisfaction After Bariatric Surgery: A Prospective Multicenter Cohort Study

Abstract

Background Postoperative pain remains a clinical priority in bariatric surgery because of its impact on recovery, patient satisfaction, and postoperative complications. However, pain management after bariatric surgery is challenging because of inherent risks, such as respiratory complications, particularly in patients with obstructive sleep apnea (OSA). Current pain management strategies in bariatric surgery remain insufficient, with moderate-to-severe pain reported in 30-50% of patients within 24 hours postoperatively and up to 75% in those using intravenous (IV) patient-controlled analgesia (PCA) after post-anesthesia care unit (PACU) discharge, despite multimodal approaches. Objectives To identify perioperative predictors of severe postoperative pain and patient satisfaction after bariatric surgery. This study aimed to characterize the postoperative pain trajectory and guide future interventional trials in bariatric patients. Methods In this prospective multicenter observational cohort study, 420 adults undergoing bariatric surgery under general anesthesia were followed for the first 48 hours. Data collected included patient demographics, perioperative predictors of postoperative pain, and postoperative pain outcomes at multiple time points from the PACU through 48 hours postoperatively. Pain intensity was measured using the Numerical Rating Scale (NRS) from 0-10, and severe pain was defined as a pain score of >7/10 within the first 24 hours. Patient satisfaction (0-10) and overall pain relief (0-100) were recorded. Secondary outcomes included other pain outcomes during the first 48 hours after surgery. Multivariate logistic regression was used to identify independent predictors of severe postoperative pain, and linear regression analysis was used to identify predictors of patient satisfaction. Results Preliminary findings indicate that 153 of 420 patients (36.4%) experienced severe pain during the first 24 hours. Mean satisfaction was 7.14+1.75, and overall pain relief at 24 hours was 7.14+1.752. Predictors of severe pain included preoperative anxiety, female gender, smoking, preoperative chronic pain, worst postoperative pain, and a greater need for analgesics (all P < 0.05). The strongest predictor of severe pain was uncontrolled early worst pain (regression coefficient = +2.41, OR = 11.13 for worst pain, and P <0.001). The area under the receiver operating characteristic (ROC) curve (AUC) = 0.81 for severe pain, and it had a pseudo‑R² of 0.18. The strongest predictor of high satisfaction was effective pain relief (regression coefficient = +1.2, and P <0.001). Other predictors of higher satisfaction included preoperative patient education, local anesthetic (LA) infiltration, the use of postoperative regional anesthesia (RA), and PCA (OR 0.055-0.056 for RA/PCA). An R² value of 0.855 for satisfaction indicates that 85.5% of the variance in satisfaction scores is explained by the predictors. Conclusions In this multicenter cohort, severe postoperative pain remained prevalent after bariatric surgery. Targeting modifiable perioperative predictors, such as preoperative anxiety, preexisting pain, and uncontrolled early postoperative pain, may reduce the incidence of severe pain. Furthermore, adopting multimodal analgesia strategies, including pre-incisional LA infiltration, postoperative RA, PCA, and structured patient education, may improve overall outcomes and enhance patient satisfaction.