The role of preoperative blood eosinophil counts in distinguishing chronic rhinosinusitis with nasal polyps phenotypes

Background Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common heterogenous disease in the patients with chronic airway diseases. This study investigated the role of blood eosinophil count (BEC) in the classification of CRSwNP and its recurrence in eosinophilic CRSwNP. Methods Sixty‐five patients who underwent nasal endoscopic resection of CRSwNP were recruited and divided into eosinophilic CRSwNP and non‐eosinophilic CRSwNP groups based on the levels (10% cutoff) of eosinophil infiltration as indicated by hematoxylin and eosin (H&E) staining. Results We recruited 30 patients in the eosinophilic CRSwNP group and 35 patients in the non‐eosinophilic CRSwNP group. The outcome of preoperative visual analogue scale (VAS) score, preoperative Lund‐Mackay score, and preoperative Lund‐Kennedy score between the 2 groups were comparable. The level of BEC in the eosinophilic CRSwNP group was significantly higher than that of non‐eosinophilic CRSwNP group (0.79 ± 0.27 × 10 9 /L vs 0.30 ± 0.22 × 10 9 /L; p < 0.001). We observed a statistical significance in the number of H&E eosinophils (29.11 ± 2.93 vs 3.17 ± 0.51; p < 0.001) and CRSwNP phenotypes (eosinophilic/non‐eosinophilic, 28/3 vs 2/32; p < 0.001) when the cutoff value of BEC was set at 0.39 × 10 9 /L. The disease‐free recurrence (DFR) was found to be statistically significant when the cutoff value of BEC was 0.73 × 10 9 /L in eosinophilic CRSwNP ( p = 0.009). Conclusion Results indicate that BEC may be capable of distinguishing CRSwNP phenotypes as well as predicting polyp recurrence in eosinophilic CRSwNP. Given the relatively small sample size, further studies will be necessary to confirm a role for BEC as a systemic biomarker in CRSwNP.