Relationship between preoperative serum cystatin C concentration and postoperative delirium / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the relationship between preoperative serum cystatin C (Cys C) concentration and postoperative delirium (POD) in the patients.Methods:Three hundred and ninety patients, aged >50 yr, of American Society of Anesthesiologists Physical Status classification Ⅰor Ⅱ, scheduled for elective knee and hip replacement under combined spinal-epidural anesthesia, with Mini-Mental State Examination scores >23 at 1 day before operation, were included in the study. Peripheral blood samples were collected before operation, and the serum Cys C concentration was measured by the latex-enhanced immunoturbidimetric assay. The cerebrospinal fluid (CSF) 2 ml was collected after successful spinal-epidural puncture for determination of amyloid-β 42 (Aβ42), total tau (T-tau) and phosphorylated tau (P-tau) concentrations by enzyme-linked immunosorbent assay. The patients were divided into POD group and non-POD group according to whether POD occurred. The logistic regression analysis was used to identify the risk and protective factors for POD, and the mediating effect of CSF biomarkers was analyzed. The receiver operating characteristic curve was drawn to evaluate the accuracy of serum Cys C concentration and combination of serum Cys C conceatration and CSF biomarker concentration in predicting POD.Results:Three hundred and twenty-seven patients were finally enrolled, and the incidence of POD was 13.5%. The results of logistic regression showed that increased serum Cys C concentration and increased concentrations of P-tau and T-tau in CSF were risk factors for POD, while increased concentration of Aβ42 and increased Aβ42/P-tau ratio and Aβ42/T-tau ratio in CSF were protective factors for POD ( P<0.05) after adjusting for multiple confounding variables such as age, sex, years of education, Mini-Mental State Examination score, smoking history, drinking history, hypertension and diabetes history. The mediation analysis showed that the relationship between serum Cys C concentration and POD was mediated by T-tau concentration in CSF (11.1%) and by Aβ42/T-tau ratio in CSF (18.0%). The area under the receiver operating characteristic curve of serum Cys C and CSF biomarker concentrations in predicting POD was 0.807 ( P<0.001). Conclusions:Increase in preoperative serum Cys C concentration is a risk factor for POD. T-tau concentration and Aβ42/T-tau ratio in CSF serve as the key mediators in the relationship between preoperative serum Cys C concentration and POD.