Duration of Olfactory Loss and Steroid Responsiveness as Predictors of Treatment Response to Dupilumab in Chronic Rhinosinusitis With Nasal Polyps

Background Olfactory dysfunction affects 60%–80% of patients with chronic rhinosinusitis with nasal polyps (CRSwNP). Dupilumab improves olfactory outcomes in CRSwNP, but the degree of improvement varies among patients. This study examined whether duration of olfactory loss, steroid responsiveness, and baseline smell fluctuation are associated with dupilumab treatment response. Methods CRSwNP patients initiating dupilumab were enrolled in a single‐arm, prospective study. Duration of olfactory loss, steroid responsiveness, and baseline smell fluctuation were recorded. Olfactory testing using Sniffin' Sticks (threshold, discrimination, identification, and composite TDI score) and patient‐reported smell ability were documented at baseline and after 12 weeks of dupilumab. The relationship between these clinical features and olfactory outcomes was analyzed. Results Patients who reported a shorter duration of olfactory loss had greater TDI improvement ( R 2 = 0.089, p = 0.02) after dupilumab. Specifically, patients with less than 10 years of olfactory loss demonstrated significantly greater TDI improvement compared with those with longer duration (10.9 vs. 4.5 points, p = 0.01), a difference which exceeded the minimal clinically important difference of 5.5 points. Steroid‐responsive patients showed higher change scores across several measures, including patient‐reported olfaction and smell identification scores, although there was no overall difference in TDI improvement. Patients reporting baseline smell fluctuation had higher TDI scores throughout treatment but showed similar magnitude of change. Conclusions Duration of olfactory loss is associated with dupilumab treatment response in CRSwNP, with a 10‐year threshold identifying patients less likely to achieve clinically meaningful improvement. Steroid responsiveness provides additional prognostic value. These readily available clinical features can guide patient counseling and treatment expectations.