Daytime dysfunction may be associated with postoperative delirium in patients undergoing total hip/knee replacement: The PNDABLE study

PurposePostoperative delirium (POD) is a usual complication after total hip/knee replacement, which may be affected by sleep characteristics. However, up to now, preoperative sleep characteristics have not been evaluated as risk factors of POD. The relationship between self-reported sleep characteristics and POD in patients has been investigated in this study.Patients and MethodsWe recruited 495 cognitively intact individuals in the final analysis from the Perioperative Neurocognitive Disorder and Biomarker Lifestyle study. Sleep characteristics were tested by the Pittsburgh Sleep Quality Index (PSQI). Mini-mental state examination was applied to assess preoperative mental status of patients. Postoperatively, we used confusion assessment method and memorial delirium assessment scale to evaluate the incidence of POD and POD severity, respectively. The cerebrospinal fluid (CSF) levels of T-tau, P-tau, A beta 40, and A beta 42 were detected by enzyme-linked immune-sorbent assay before the operation. Logistic regression, multiple linear regression, and mediation effects were performed to analyze the relationship between self-reported sleep characteristics and POD.ResultsPOD was detected in 11.31% (56/495) of the patients, with logistic regression analysis showing that daytime dysfunction, P-tau, and T-tau were risk factors of POD, and A beta 42 was a protective factor of POD. Multiple linear regression analysis confirmed that daytime dysfunction was positively correlated with P-tau in patients with POD. Meanwhile, compared to the patients with no postoperative delirium, the CSF levels of P- and T-tau were higher in patients with POD. Furthermore, mediation analysis showed that it was probable that daytime dysfunction mediated POD through P-tau (proportion: 12.90%) partially.ConclusionDaytime dysfunction is a risk factor of POD preoperatively. To sum up, CSF P-tau protein might partially mediate the influence of daytime dysfunction on POD.Clinical trial registrationThis study was registered at Chinese Clinical Trial Registry (ChiCTR2000033439). Daytime dysfunction is one of the risk factors for POD, which may be mediated through P-tau partially. Avoiding daytime dysfunction and maintaining a sufficient sleep might help prevent POD.image