Abstract: Objective To investigate the correlation between perioperative dynamic change of C-reactive protein (ΔCRP) and postoperative delirium (POD), and to evaluate its predictive value for POD. Methods A total of 574 elderly patients undergoing elective general anesthesia at the Second Affiliated Hospital of Nanjing Medical University from February 2021 to July 2025 were enrolled and divided into a POD group (n=118) and a non-POD (N-POD) group (n=456) based on the occurrence of POD. Baseline data and laboratory test results were collected, and the CRP levels one day before surgery and the highest CRP value within three days after surgery were recorded to calculate ΔCRP. The correlation of ΔCRP level with POD was analyzed and the predictive value of ΔCRP level for POD was assessed. Results POD occurred in 118 patients. Compared with N-POD group, the proportion of urban residents, educational level, preoperative mini-mental state examination (MMSE) scores, the levels of red blood cells, hemoglobin, albumin, alanine aminotransferase, and creatine kinase were significantly lower, while American Society of Anesthesiologists (ASA) classification, intraoperative blood loss, total intraoperative fluid input, operation time, and the levels of prothrombin time, fibrinogen, D-dimer, preoperative CRP, postoperative CRP, and ΔCRP were significantly higher in POD group (P<0.05). Multivariable logistic regression analysis showed significant association between ΔCRP and POD (increased by 1 mg/L: OR=1.013, 95%CI: 1.008－1.018; increased by 10 mg/L: OR=1.136, 95%CI: 1.079－1.196). The patients were divided into 4 groups according to quartile of ΔCRP, and the risk of POD in Q4 group was significantly increased (OR=5.078, 95%CI: 2.332－11.059). The AUC of ΔCRP for predicting POD was 0.788 (95%CI: 0.746－0.830). Conclusions Perioperative ΔCRP exhibits a significant dose-dependent positive correlation with the risk of POD and is an independent risk factor for POD occurrence.

Key words: C-reactive protein, general anesthesia, postoperative delirium, dynamic change of C-reactive protein, aged