Predictive model for postoperative unrecovered olfactory function in CRSwNP patients with olfactory disorder

Olfactory disorder (OD) is a prevalent and challenging symptom in chronic rhinosinusitis with nasal polyps (CRSwNP). This study aims to investigate the risk factors and develop a predictive model for poor olfactory prognosis in CRSwNP patients with OD after endoscopic sinus surgery (ESS).

Seventy-eight CRSwNP patients with OD who underwent ESS were enrolled. Preoperative and 6-month-postoperative olfactory function were assessed using Sniffin' Sticks. Receiver operating characteristics (ROC) curves were constructed to set the cutoff points. Risk factors were determined by logistic models. A power analysis was conducted to evaluate the sample size.

Overall, 66.7% of CRSwNP patients had unrecovered olfaction after surgery. Patients with unrecovered olfaction displayed higher preoperative threshold-discrimination-identification (TDI) score, lower Questionnaire for Olfactory Disorders-Negative Statements (QOD-NS) score, lower total olfactory cleft score (TOCS), and fewer tissue eosinophils than those of the improved/recovered group. QOD-NS ≤ 5.0, preoperative TOCS ≤ 4.5 and tissue eosinophil count ≤ 8.3 were independent risk factors for unrecovered olfaction. Based on these variables, a predictive model was developed. The area under the ROC curve for the model was 0.845, and the optimal cutoff value was 2.0 points, with a sensitivity of 82.7% and specificity of 80.8%.

Low levels of QOD-NS score (preoperative), TOCS (preoperative) and tissue eosinophil count are independent risk factors for short-term unrecovered olfaction in CRS patients with OD postoperatively. The predictive model developed here is practical and convenient for the early identification of poor prognosis of OD, enabling early additional intervention.