The effect of early postoperative acute pain on postoperative delirium in elderly patients undergoing abdominal surgery:a secondary analysis of multicenter prospective data

Purpose Against the backdrop of global population aging, the number of elderly patients undergoing surgical procedures continues to increase. These patients frequently experience postoperative acute pain and delirium, however, there is little clinical data on their possible interrelationships. Methods A secondary analysis of multicenter prospective data, including tertiary hospitals in Five Chinese Regions, from April 2020 to April 2022 .Elderly patients (≥ 65 years) scheduled for elective abdominal surgery under general anesthesia, without auditory, visual, or cognitive impairments, who completed assessments for postoperative delirium, anxiety, and depression.The impact of early postoperative acute pain on postoperative delirium in elderly patients undergoing abdominal surgery was evaluated using univariate and multivariate logistic regression, propensity score matching, and subgroup analysis. Results This study included 2,674 patients. Delirium occurred in 13.2% (n = 354) of patients in postoperative 7 days (POD 7), with significantly higher prevalence in the moderate-to-severe pain group (unadjusted: 16.3 vs. 9.6%, P  < 0.001). Moderate-to-severe pain on POD1 showed a significant association with delirium occurrence in POD 7 according to univariate logistic regression (OR 1.831, 95% CI 1.445 to 2.319, P  < 0.001), multivariable logistic regression (OR 1.629, 95% CI 1.274 to 2.084, P  < 0.001), and propensity score matching (PSM) model (OR 1.443, 95% CI 1.108 to 1.879, P  = 0.006). Conclusion In elderly patients undergoing elective abdominal surgery, moderate-to-severe pain on POD 1 was significantly associated with both delirium and depressive symptoms within 7 days of surgery. Improved early postoperative analgesic strategies may aid in preventing delirium. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT06964893 (2025-05-07 )