Associations between Alzheimer's disease biomarkers and postoperative delirium or cognitive dysfunction

BACKGROUNDThe relationship between Alzheimer's disease biomarkers and postoperative complications, such as postoperative delirium (POD) and postoperative cognitive dysfunction (POCD), remains a subject of ongoing debate.OBJECTIVEThis meta-analysis aimed to determine whether there is an association between perioperative Alzheimer's disease biomarkers and postoperative complications.DESIGNWe conducted a meta-analysis of observational clinical studies that explored the correlation between Alzheimer's disease biomarkers and POD or POCD in patients who have undergone surgery, following PRISMA guidelines. The protocol was previously published (INPLASY: INPLASY202350001).DATA SOURCESA comprehensive search was conducted across PubMed, Embase, Web of Science, and Cochrane databases until March 2023.ELIGIBILITY CRITERIASurgical patients aged at least 18 years, studies focusing on POD or POCD, research involving Alzheimer's disease biomarkers, including A beta or tau in blood or cerebrospinal fluid (CSF), and availability of the full text.RESULTSOur meta-analysis included 15 studies: six focusing on POD and nine on POCD. The findings revealed a negative correlation between preoperative CSF beta-amyloid 42 (A beta 42) levels and the onset of POD [mean difference -86.1, 95% confidence interval (CI), -114.15 to -58.05, I2: 47%]; this association was strongly supported by trial sequential analysis (TSA). A similar negative correlation was discerned between preoperative CSF A beta 42 levels and the incidence of POCD (-165.01, 95% CI, -261.48 to -68.53, I2: 95%). The TSA also provided robust evidence for this finding; however, the evidence remains insufficient to confirm a relationship between other Alzheimer's disease biomarkers [beta-amyloid 40 (A beta 40), total tau (T-tau), phosphorylated tau (P-tau), and A beta 42/T-tau ratio] and POD or POCD.CONCLUSIONThe study results indicate a negative correlation between preoperative CSF A beta 42 levels and the occurrence of both POD and POCD. Future investigations are warranted to identify the predictive cutoff value of preoperative CSF A beta 42 for POD and POCD.