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.