Dynamic changes in serum neuregulin-1 and their association with postoperative delirium after laparoscopic gastrointestinal surgery in elderly patients.

OBJECTIVE: Postoperative delirium is a frequent complication in older adults following gastrointestinal surgery, and perioperative inflammatory activation has been implicated in its pathogenesis. This study investigated whether perioperative serum neuregulin-1 levels were associated with postoperative delirium and evaluated the discriminative performance for postoperative risk stratification of neuregulin-1. METHODS: In this prospective cohort study, 512 patients aged ≥65 years undergoing elective laparoscopic gastrointestinal surgery were enrolled. Postoperative delirium was assessed twice daily during the first 3 postoperative days using the Confusion Assessment Method and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. Serum neuregulin-1, interleukin-6, interleukin-17, tumor necrosis factor-α, and C-reactive protein were measured preoperatively and at 6 hours, 24 hours, and 72 hours postoperatively. Receiver operating characteristic curves and multivariable logistic regression were used to assess discriminative value and independent associations. RESULTS: Postoperative delirium occurred in 93 of 512 patients (18.2%). Compared with non-postoperative delirium patients, those who developed postoperative delirium had lower preoperative Mini-Mental State Examination scores and higher American Society of Anesthesiologists class, longer operation and anesthesia durations, greater intraoperative blood loss, and a higher incidence of intraoperative hypothermia. Serum neuregulin-1 levels were significantly lower in postoperative delirium patients compared with non-postoperative delirium patients at 6 hours, 24 hours, and 72 hours after surgery. Receiver operating characteristic curve analysis showed that neuregulin-1 at 24 hours after surgery showed the best discriminative performance for postoperative delirium risk stratification with an area under the curve of 0.750 (95% confidence interval, 0.701-0.799), a cutoff value of 251.55 pg/mL, sensitivity of 67.1%, and specificity of 64.5%. In the multivariate logistic regression analysis, lower neuregulin-1 at 24 hours (odds ratio, 0.964; 95% confidence interval, 0.954-0.975; P < .001) was independently associated with postoperative delirium. CONCLUSION: Lower perioperative serum neuregulin-1 levels, particularly at 24 hours after surgery, were strongly associated with postoperative delirium in elderly patients undergoing gastrointestinal surgery. Measurement of neuregulin-1 at 24 hours after surgery may serve as a practical postoperative biomarker for risk stratification and closer clinical surveillance in elderly patients undergoing gastrointestinal surgery.