[Analysis of influencing factors on postoperative olfactory function in patients with chronic rhinosinusitis with nasal polyps].

Objective: To analyze the recovery of olfactory function in patients diagnosed with chronic rhinosinusitis with nasal polyps (CRSwNP) after endoscopic sinus surgery and to identify factors influencing recovery to provide a theoretical foundation for taking effective measures. Methods: This was a retrospective analysis included 277 CRSwNP patients with olfactory dysfunction who underwent endoscopic sinus surgery at the First Affiliated Hospital of Chongqing Medical University from October 2021 to September 2023. This study included 189 males and 88 females, with a median age of 46 years (range: 18-84 years). Routine laboratory tests, sinus CT Lund-Mackay score, modified sinus CT score, endoscopic polyp score, and nasal endoscopic Lund-Kennedy score were included for preoperative assessments. Eosinophil counts were obtained from nasal polyp tissues during surgery. The University of Pennsylvania smell identification test (UPSIT) was administered before surgery and 6 months after surgery to evaluate olfactory function. Based on results of postoperative olfactory test, patients were divided into two groups: the group with improved olfactory function and without improvement of olfactory function. Chi-square test and multivariate Logistic regression were used to analyze relevant factors affecting postoperative olfactory function of CRSwNP patients, and the prediction model was constructed to verify its consistency and to analyze its prediction efficiency. Results: Of the 277 patients, 155 (56%) showed improved olfactory function and 122 (44%) did not improve after surgery. Multivariate Logistic regression analysis identified following independent factors associated with improved postoperative olfactory function: concurrent allergic rhinitis (OR=2.34), long duration of olfactory dysfunction (OR=1.13), higher total score of CT olfactory zone (OR=1.26), higher Lund-Kennedy score (OR=1.23), presence of olfactory cleft polyps (OR=4.72), higher tissue eosinophil count (OR=1.01) and high IL-6 levels (OR=1.51). Conversely, a higher endoscopic polyp score (OR=0.74) was associated with a lower likelihood of olfactory improvement. The nomogram model, validated using receiver operating characteristic (ROC) analysis, demonstrated good clinical efficacy with an area under the curve (AUC) of 0.80 (95%CI: 0.748-0.852). The calibration curve showed an absolute error of 0.021, indicating good consistency and predictive accuracy. Conclusions: Factors such as a medical history of allergic rhinitis, duration of olfactory dysfunction, total score of sinus CT olfactory zone, endoscopic Lund-Kennedy score, olfactory cleft polyps, tissue eosinophil count, IL-6 level and endoscopic polyp score independently influence postoperative olfactory function of CRSwNP patients. The nomogram model based on these independent factors has good clinical efficacy, which can be used to predict the postoperative olfactory function in CRSwNP patients with olfactory dysfunction.