[Analysis of factors affecting olfactory disfunctions in patients with chronic rhinosinusitis with nasal polyps]

Objective: To analyze the factors affecting olfactory disfunctions in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Methods: This was a retrospective analysis. Eighty-eight patients with CRSwNP who underwent endoscopic sinus surgery in Beijing Anzhen Hospital from 2014 to 2018 were enrolled, including 22 males and 66 females, with the age of (48.1±11.3) years old(Mean±SD). Sniffin' Sticks olfactory test, Lund-Mackay score and modified sinus CT olfactory cleft score, nasal resistance and acoustic reflex examination, blood routine and blood biochemistry test, serum specific IgE test were performed before surgery and nasal polyps of all patients were collected for eosinophil count during surgery. According to bilateral total TDI score, the patients were divided into normal olfactory function group and olfactory disfunction group. The clinical baseline data were compared between the two groups. According to the results of single factor analysis, factors which were significant different between the two groups and clinically useful indicators were further included in the multivariate Logistic regression model analysis, then a model predicting olfactory disfunction in patients with CRSwNP was initially established. P<0.05 was considered statistically significant. Results: Among 88 patients with CRSwNP, 32 (36.4%) patients were with normal olfaction and 56 (63.6%) patients were with olfactory disfunction, including 40 (45.5%) of hyposmia and 16 (18.2%) of anosmia. Tissue eosinophil count, blood eosinophil percentage and blood urea concentration had significant difference between the two groups (12.7[2.0, 52.3]/HP (M[P(25), P(75)]) vs 38.6[16.2, 87.0]/HP, 2.75[1.60, 4.80]% vs 4.35[2.50, 6.60]%, (5.56±1.15) mmol/L vs (4.98±1.33) mmol/L, all P<0.05). Modified sinus CT olfactory cleft score and Lund-Mackay score except for ostiomeatal complex score were statistically significant between the two groups (all P<0.05). Multivariate Logistic regression analysis showed that the bilateral and total olfactory cleft score and blood urea concentration were statistically significant, in addition, the bilateral and total olfactory cleft score was a risk factor (OR=2.108, 95%CI: 1.407-3.159, P<0.001) and blood urea within a certain concentration was a protective factor (OR=0.461, 95%CI: 0.240-0.884, P=0.020). Further studies found that the area under the ROC curve of the model with tissue eosinophil count, blood eosinophil percentage, bilateral and total olfactory cleft score, total inspiratory volume and blood urea concentration was 0.888 (P<0.01), which had good predictive value for olfactory disorders in CRSwNP. Conclusions: The modified sinus CT olfactory cleft score is closely related to the olfactory disorders in patients with CRSwNP. A certain degree of elevated blood urea concentration may have a protective effect on the olfactory function of patients with CRSwNP.