Development of Sinonasal Outcome Test (SNOT‐22) Domains in Chronic Rhinosinusitis With Nasal Polyps

OBJECTIVES/HYPOTHESIS: The 22‐item Sinonasal Outcome Test (SNOT‐22) is a validated chronic rhinosinusitis health‐related quality‐of‐life outcome (HRQoL) measure; however, SNOT‐22 domains have not been validated specifically for chronic rhinosinusitis with nasal polyps (CRSwNP). STUDY DESIGN: Validation of SNOT‐22 domain structure, using data from 3 randomized, placebo‐controlled, double‐blinded, multicenter clinical trials of dupilumab in adults with moderate‐to‐severe CRSwNP. METHODS: Preliminary dimensional structure was derived by exploratory factor analyses of SNOT‐22 data from a phase 2 trial (NCT01920893) of dupilumab for the treatment of CRSwNP. Data from 2 phase 3 clinical trials (NCT02912468 and NCT02898454) were then used for confirmatory factor analysis, and evaluated for reliability, construct validity, and responsiveness. In all three trials, the SNOT‐22 was administered electronically on a tablet and trial participants were required to answer all items. RESULTS: Factor analysis supported five domains: Nasal, Ear/Facial, Sleep, Function, and Emotion. Correlations between domains were moderate to high, ranging from 0.53 (Nasal–Emotion) to 0.88 (Function–Sleep). Construct validity was mostly supported; relationships with other measures were almost always in the intended direction and magnitude. Internal consistency reliability also confirmed questionnaire structure with strong Cronbach's alpha values (all >0.80). Moderate‐to‐high correlations were observed between change in SNOT‐22 domain scores and other study patient‐reported outcome measures, along with large effect‐size estimates (≥0.7), demonstrating responsiveness of the Nasal, Sleep, and Function domains. Emotion and Ear/Facial domains had small‐to‐moderate effect sizes. CONCLUSIONS: Psychometric analyses support the validity, reliability, and responsiveness of five domains of SNOT‐22 (Nasal, Ear/Facial, Sleep, Function, and Emotion) for assessing symptoms and impact on HRQoL in patients with CRSwNP. Laryngoscope, 132:933–941, 2022