The Relationship Between Decreased Serum Klotho Protein and Cognitive Impairment in Patients After Abdominal Surgery

Postoperative cognitive dysfunction (POCD) is a common complication in elderly patients undergoing abdominal surgery; however, reliable biomarkers for its early identification are limited. Klotho, an anti-aging protein with neuroprotective and anti-inflammatory properties, may play a role in POCD development. This study investigated the association between serum Klotho levels and POCD, as well as their relationships with inflammation and cognitive outcomes.

A total of 93 patients undergoing abdominal surgery were enrolled and classified into non-POCD (n = 59) and POCD (n = 34) groups based on their postoperative Montreal Cognitive Assessment (MoCA) scores. Serum Klotho, C-reactive protein (CRP), interleukin (IL)-1β, and IL-6 levels were measured preoperatively and postoperatively. Multivariate logistic regression, receiver operating characteristic (ROC) curve analysis, and Pearson correlation analyses were performed to evaluate associations and predictive value.

Patients who developed POCD had significantly longer durations of anesthesia than those without POCD (all P < 0.001). While preoperative Klotho levels were comparable between the groups, postoperative serum Klotho levels were significantly reduced in the POCD group (561.07 ± 59.27 vs. 654.66 ± 94.63 pg/mL, P < 0.001). Multivariate analysis identified age (odds ratio [OR] = 1.101, 95% confidence interval [CI] = 1.009-1.201, P = 0.031) and anesthesia duration (OR = 1.059, 95% CI = 1.011-1.109, P = 0.015) as independent risk factors, whereas higher postoperative Klotho levels were independently associated with a reduced risk of poor outcomes (OR = 0.992, 95% CI = 0.985-0.998, P = 0.016). Postoperative Klotho levels were negatively correlated with anesthesia duration and inflammatory markers (C-reactive protein, interleukin [IL]-1 β, and IL-6) (all P < 0.05) and positively correlated with postoperative MoCA scores (r = 0.45, P < 0.001). ROC analysis identified an optimal cutoff value of 630.2 pg/mL for Klotho in distinguishing POCD, demonstrating favorable diagnostic performance.

Decreased postoperative serum Klotho levels are closely associated with increased inflammation and cognitive impairment following abdominal surgery. Klotho may serve as a promising biomarker for the early identification of POCD and as a potential therapeutic target to improve postoperative cognitive outcomes.