Tissue Eosinophils Threshold and its Association With Adult‐Onset Asthma in Chronic Rhinosinusitis

ABSTRACT Introduction Tissue eosinophil counts (TEC) might serve as a biomarker linking chronic rhinosinusitis (CRS) and the presence of adult‐onset asthma. This study aimed to determine if TEC in sinus mucosa/polyps in CRS patients is an independent indicator of asthma and to identify its optimal cut‐off point. Methods This cross‐sectional study was conducted on primary CRS patients scheduled for surgery. All patients were assessed by a pulmonologist for asthma diagnosis. Tissues were collected during surgery and evaluated for TEC. Logistic regression and receiver operating characteristic analysis were used to determine significant factors and the optimal cut‐off points of TEC associated with asthma. Results A total of 103 CRS patients were included. Ten patients (9.7%) had underlying asthma, while 13 (12.6%) were first diagnosed by the pulmonologist. TEC ≥40 cells per high‐powered field (HPF) exhibited a significant correlation with asthma (area under the curve = 0.71, p < 0.001). The sensitivity of this cut‐off point was 0.70 (95% confidence interval [CI] = 0.47–0.87), and specificity was 0.66 (95% CI = 0.55–0.76). Positive predictive value and negative predictive value were 0.37 and 0.88, respectively. The cut‐off point significantly associated with the presence of asthma, with an adjusted odds ratio of 3.13 (95% CI = 1.05–9.35, p = 0.04), controlling for polyps, allergic rhinitis, and computerized tomography (CT) score. Conclusion TEC in CRS patients can help determine the presence of adult‐onset asthma, with an optimal threshold of ≥40 cells/HPF. This threshold is significantly associated with asthma independent of polyps, allergy, and CT score.