Objective:To evaluate the relationship between postoperative delirium (POD) and concentrations of phosphatidylethanolamine-binding protein 1 (PEBP1) in cerebrospinal fluid (CSF) of elderly patients undergoing total knee and hip arthroplasty.Methods:In this case-control study, 375 elderly patients of both sexes, aged ≥65 yr, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, scheduled for elective total knee and hip arthroplasty under combined spinal-epidural anesthesia at Haian Hospital Affiliated to Nantong University from November 2022 to June 2024, were selected. The perioperative clinical data were collected. CSF was drawn before anaesthesia for determination of the concentrations of PEBP1, Abeta 42 (Aβ 42), total tau (t-tau) and phosphorylated tau (p-tau) by enzyme-linked immunosorbent assay. The occurrence of postoperative delirium was evaluated using the Confusion Assessment Method at 1-7 days after operation. The severity of POD was assessed using a Memorial Delirium Assessment Scale. The patients were divided into POD group and non-POD group based on whether POD occurred. The influencing factors of POD were analyzed using multivariate logistic regression. Mediating effects were assessed to determine whether the levels of Aβ 42, p-tau and t-tau in CSF mediated PEBP1′s effect on POD. The accuracy of CSF PEBP1 concentration in predicting POD was evaluated using the receiver operating characteristic curve. Results:Decreased concentration of Aβ 42 in CSF, decreased ratios of Aβ 42/p-tau and Aβ 42/t-tau in CSF, and increased concentrations of PEBP1, p-tau and t-tau in CSF were independent risk factors for POD ( P<0.05). The results of mediation analysis showed that the relationship between PEBP1 and POD was partially mediated by CSF Aβ 42 (15.0%) and Aβ 42/t-tau ratio (14.9%). The receiver operating characteristic curve showed that the accuracy of CSF PEBP1 concentrations in predicting the occurrence of POD was high (AUC=0.846, P<0.001). Conclusions:Preoperative elevated CSF PEBP1 concentration is a risk factor for POD. CSF Aβ 42 concentration and Aβ 42/t-tau ratio serve as key mediators in the the association between PEBP1 and POD. PEBP1 concentration is more accurate in predicting POD.

Objective:To evaluate the relationship between postoperative delirium (POD) and concentrations of phosphatidylethanolamine-binding protein 1 (PEBP1) in cerebrospinal fluid (CSF) of elderly patients undergoing total knee and hip arthroplasty.Methods:In this case-control study, 375 elderly patients of both sexes, aged ≥65 yr, of American Society of Anesthesiologists Physical Status classification Ⅰ or Ⅱ, scheduled for elective total knee and hip arthroplasty under combined spinal-epidural anesthesia at Haian Hospital Affiliated to Nantong University from November 2022 to June 2024, were selected. The perioperative clinical data were collected. CSF was drawn before anaesthesia for determination of the concentrations of PEBP1, Abeta 42 (Aβ 42), total tau (t-tau) and phosphorylated tau (p-tau) by enzyme-linked immunosorbent assay. The occurrence of postoperative delirium was evaluated using the Confusion Assessment Method at 1-7 days after operation. The severity of POD was assessed using a Memorial Delirium Assessment Scale. The patients were divided into POD group and non-POD group based on whether POD occurred. The influencing factors of POD were analyzed using multivariate logistic regression. Mediating effects were assessed to determine whether the levels of Aβ 42, p-tau and t-tau in CSF mediated PEBP1′s effect on POD. The accuracy of CSF PEBP1 concentration in predicting POD was evaluated using the receiver operating characteristic curve. Results:Decreased concentration of Aβ 42 in CSF, decreased ratios of Aβ 42/p-tau and Aβ 42/t-tau in CSF, and increased concentrations of PEBP1, p-tau and t-tau in CSF were independent risk factors for POD ( P<0.05). The results of mediation analysis showed that the relationship between PEBP1 and POD was partially mediated by CSF Aβ 42 (15.0%) and Aβ 42/t-tau ratio (14.9%). The receiver operating characteristic curve showed that the accuracy of CSF PEBP1 concentrations in predicting the occurrence of POD was high (AUC=0.846, P<0.001). Conclusions:Preoperative elevated CSF PEBP1 concentration is a risk factor for POD. CSF Aβ 42 concentration and Aβ 42/t-tau ratio serve as key mediators in the the association between PEBP1 and POD. PEBP1 concentration is more accurate in predicting POD.