Serum NLRP3 levels are associated with postoperative delirium of elderly patients with lung cancer: an observational analytical study

Objective NOD-like receptor protein 3 (NLRP3) regulates the inflammatory response. This study aimed to investigate the relationship between perioperative serum NLRP3 levels and postoperative delirium (POD) in elderly patients with lung cancer. Methods In this observational analytical study, serum NLRP3 levels were measured preoperatively and postoperatively in 266 elderly patients with lung cancer and at study entry in 100 controls. We used the American Society of Anesthesiologists (ASA) Scale, Charlson Comorbidity Index (CCI), and Eastern Cooperative Oncology Group (ECOG) Scaleto classify patients’ preoperative physical fitness. Patients were assessed for POD from the first to the third postoperative day using the Chinese Confusion Assessment Method. Predictors of POD were determined using multivariate analysis. Results Preoperative and postoperative serum NLRP3 levels in patients were significantly higher than those in controls, with the highest levels observed postoperatively. Postoperative blood C-reactive protein levels and ECOG scores were independently correlated with postoperative serum NLRP3 levels. Postoperative serum NLRP3 levels, ASA classifications, and CCI were independently associated with POD. The nomogram model incorporating the three independent predictors of POD was confirmed to have good discrimination, calibration, and clinical utility based on the receiver operating characteristic curve, calibration curve, and decision curve. Compared with the clinical model (CCI + ASA), the nomogram model demonstrated significant improvement in risk reclassification, with a continuous NRI of 0.7198 (95% CI, 0.4366–1.003) and an IDI of 0.0867 (95% CI, 0.041–0.1323); however, the improvement in AUC did not reach statistical significance. Internal validation through 10-fold cross-validation demonstrated that the nomogram model had good predictive accuracy based on the optimism-corrected area under the curve. Conclusion Significantly increased postoperative serum NLRP3 levels are independently associated with POD in elderly patients with lung cancer, and the model integrating serum NLRP3 levels shows favorable predictive performance for POD.