ABSTRACT
Objective:To evaluate the association between preoperative serum β 2-microglobulin (β 2MG) concentrations and postoperative delirium (POD) in elderly patients. Methods:The study selected patients who underwent knee or hip arthroplasty under spinal-epidural anesthesia on an elective basis at Qingdao Municipal Hospital from May 2021 to November 2022. The patients were divided into a POD group and a non-POD group based on the occurrence of POD. The study was conducted as part of the Perioperative Neurocognitive Impairment and Biomarkers Lifestyle Cohort, which was a nested case-control study. The study collected baseline data from two groups of patients and analyzed the differences between them. Logistic regression was used to identify the risk factors for POD. The stability of the regression model was tested using sensitivity analysis. The mediation model was used to examine whether cerebrospinal fluid (CSF) biomarkers mediated the relationship between β 2MG and POD. The receiver operating characteristic curve was drawn and the area under the curve was calculated to evaluate the accuracy of preoperative β 2MG concentrations and CSF biomarker concentration in predicting POD. Results:There were 57 cases in POD group and 449 cases in non-POD group. The results of logistic regression analysis showed that the increased β 2MG and CSF total tau protein (t-tau) concentrations were risk factors for POD, and the increased CSF β-amyloid 42 concentration was a protective factor for POD after adjustment for multiple confounders such as age, gender, education, Mini-Mental State Examination, history of hypertension and infusion volume ( P<0.05). The results of mediation analysis showed that the serum β 2MG′s effect on POD was partly mediated by t-tau (18.1%). The results of the receiver operating characteristic curve showed that the area under the curve of the β 2MG concentration combined with the CSF biomarker concentration was 0.742. Conclusions:Elevated preoperative serum β 2MG concentration is a risk factor for POD in elderly patients, and the relationship may be partly mediated by CSF t-tau.
ABSTRACT
Objective:To evaluate the relationship between preoperative serum bilirubin concentrations and postoperative delirium (POD) in the patients undergoing knee or hip replacement.Methods:Medical records from 413 patients undergoing knee or hip arthroplasty were selected from August 2020 to October 2023 at Qingdao Municipal Hospital using a nested case-control design based on the PNDABLE study cohort. The patients were divided into POD group ( n=77) and non-POD group ( n=336) according to whether POD occurred. Univariate analysis was used to analyze the influencing factors. Logistic regression was used to identify the risk factors for POD. The significance of mediation effect was tested. The receiver operating characteristic curve was drawn to evaluate the accuracy of risk factors in predicting POD. Results:There were significant differences in age, education time, ratio of diabetes history, Memorial Delirium Assessment Scale score, total bilirubin concentration, direct bilirubin concentration, indirect bilirubin concentration, Aβ 42 concentration, p-tau concentration, t-tau concentration, Aβ 42/p-tau ratio and Aβ 42/t-tau ratio between POD group and non-POD group ( P<0.05). The results of logistic regression analysis showed that preoperative serum total bilirubin, direct bilirubin and indirect bilirubin were risk factors for POD ( P<0.05). The results of mediation effects showed that the concentration of total tau protein in CSF partly mediated the relationship between high serum total bilirubin, direct bilirubin and indirect bilirubin concentrations and POD. The area under the receiver operating characteristic curve of total bilirubin, direct bilirubin and indirect bilirubin combined with CSF biomarker concentrations in predicting POD was 0.83 ( P<0.001). Conclusions:Preoperative elevated concentrations of total bilirubin, direct bilirubin and indirect bilirubin are risk factors for POD in the patients undergoing knee or hip replacement. CSF t-tau concentration has a partly mediating role in the association between serum total bilirubin, direct bilirubin and indirect bilirubin concentrations and the development of POD.