Relationship between preoperative levels of serum uric acid and postoperative delirium / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the relationship between preoperative levels of serum uric acid (SUA) and postoperative delirium (POD).Methods:Seven hundred and fifty patients of either sex, aged 50-90 yr, with American Society of Anesthesiologists physical status Ⅰ or Ⅱ, scheduled for elective knee replacement under spinal-epidural anesthesia, were selected.Venous blood samples were collected before anesthesia and levels of SUA were determined by enzyme-coupled assay.L 3-4 was selected as the puncture space, and the cerebrospinal fluid (CSF) specimens were obtained from the subarachnoid space for determination of concentrations of β-amyloid 42, total tau (t-tau) and phosphorylated tau (p-tau) by enzyme-linked immunosorbent assay.The patients were divided into hyperuric acid group (group HS) and non-hyperuric acid group (group NS) according to clinical diagnostic criteria of hyperuricemia, and into POD group (group POD) and non-POD group (group NPOD) according to the occurrence of POD.Logistic regression was used to identify the risk factors for POD.The mediating effect of CSF biomarkers was analyzed.The efficacy of SUA and CSF biomarker concentrations in predicting POD was evaluated using the receiver operating characteristic curve. Results:A total of 699 patients were finally enrolled in the study, and the incidence of POD was 21.5%.The results of logistic regression analysis after adjusting for multiple confounding factors, such as age, sex, years of education, Mini-Mental State Examination score, smoking history, drinking history, hypertension and diabetes history, showed that increased concentrations of SUA and p-tau and t-tau in CSF were risk factors for POD ( P<0.05). The results of mediation analysis showed that the concentrations of p-tau and t-tau in CSF were the mediating factors of the relationship between SUA and POD, with mediating effects of 0.000 301 (95% confidence interval 0-0.000 152) and 0.000 236 (95% confidence interval 0-0.000 092), respectively, and the intermediary proportion were 14.9% and 11.7%, respectively.The area under the receiver operating characteristic curve of SUA in predicting POD was 0.774 ( P<0.05). Conclusions:Increased preoperative SUA is a risk factor for POD, and the accuracy of predicting POD is high, and concentrations of p-tau and t-tau in CSF are mediators of SUA affecting POD.