PURPOSE: This study aimed to investigate the impact of baseline nasal polyp score (NPS) on the effectiveness of dupilumab treatment in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). METHODS: In this retrospective observational study, 80 CRSwNP patients treated with dupilumab 300 mg biweekly at a tertiary referral center were stratified according to the baseline NPS into two groups: low-NPS (<
5) and high-NPS (≥ 5). Treatment outcomes were evaluated at the 6-month follow-up visit and compared. RESULTS: Both groups showed significant clinical improvements. The NPS decreased significantly in both low- and high-NPS groups, from a mean score of 3.2 to 0.8 and from 6.1 to 1.4, respectively (p <
0.001 for both). SNOT-22 scores improved significantly in both groups (p <
0.001 for both), though the reduction was greater in the high-NPS group (35.5 vs. 23.9, p = 0.018). There were no significant differences between low- and high NPS groups in proportions of NPS reduction of ≥ 1 (89% vs. 95%, p = 0.396) and clinically significant SNOT-22 improvement (= reduction >
12 or follow-up SNOT <
40
80% vs. 86%, p = 0.544). CONCLUSIONS: Our results suggests that dupilumab is effective in CRSwNP treatment, regardless of baseline nasal polyp size. Both small and large polyp groups showed significant improvements in NPS and patient-reported outcome measures. Future, prospective studies are warranted to validate these findings.