Preoperative butyrylcholinesterase activity and risk of postoperative delirium: A meta-analysis.

BACKGROUND: Postoperative delirium (POD) is a common and serious complication in surgical patients, particularly older adults. Alterations in cholinergic function have been implicated in its pathophysiology. AIM: To evaluate the association between preoperative serum cholinesterase (ChE) activity-specifically butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE)-and the risk of POD in adult surgical patients in a meta-analysis. METHODS: A systematic search was conducted in PubMed, EMBASE, and Web of Science up to March 28, 2025 for studies reporting preoperative serum BuChE or AChE activity in relation to subsequent POD incidence. Standardized mean differences (SMDs) and odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using random-effects models. Subgroup and sensitivity analyses were performed based on follow-up duration and analytic models. RESULTS: Thirteen studies (n = 2730 patients) were included. Patients who developed POD had significantly lower preoperative BuChE activity than those who did not (SMD = -0.28; 95%CI: -0.39 to -0.16; I² = 18%). Higher BuChE activity was associated with a reduced risk of POD (OR per 100 unit increment = 0.97; 95%CI: 0.95-0.99; I 2 = 0%). In contrast, pooled AChE activity did not differ significantly between POD and non-POD groups (SMD = -0.25; 95%CI: -0.53 to 0.03; P = 0.08; I 2 = 80%), and the ORs per 1 unit increment in AChE activity were not statistically significant (OR = 0.98; 95%CI: 0.95-1.01). CONCLUSION: Lower preoperative serum BuChE activity is associated with an increased risk of POD in adults undergoing surgery. BuChE activity may serve as a potential preoperative biomarker for POD risk stratification.