Psychometric and Clinimetric Validity of the 20‐Item Sino‐Nasal Outcome Test (Snot‐20)

TLDR

A reliable measure of rhinosinusitis health status and quality of life is essential for assessing treatment effectiveness, and the SNOT‑20 is a 20‑item adaptation of the 31‑item Rhinosinusitis Outcome Measure. The study aimed to evaluate the psychometric and clinimetric validity of the SNOT‑20, a disease‑specific quality‑of‑life instrument for rhinosinusitis. Patients completed the SNOT‑20 by rating impact in each domain and selecting their five most important items; 102, 72, and 46 patients completed the instrument at baseline, 6 months, and 1 year post‑treatment. The SNOT‑20 demonstrated excellent reliability (Cronbach’s α = 0.9, test‑retest r = 0.9) and validity, with higher scores reflecting greater disease burden and greater change scores indicating clinical improvement; items deemed important had higher scores and larger changes, confirming the instrument’s sensitivity to clinical change.

Abstract

A valid measure of rhinosinusitis health status and quality of life is required for the complete assessment of treatment effectiveness. The purpose of this study was to analyze the psychometric and clinimetric validity of the 20-Item Sino-Nasal Outcome Test (SNOT-20), a disease-specific, health-related quality-of-life measure for rhinosinusitis. The SNOT-20 is a modification of the 31-Item Rhinosinusitis Outcome Measure, and it contains 20 nose, sinus, and general items. To complete the instrument, patients indicate how much they are affected in each area and identify the 5 most important items. The SNOT-20 was completed by 102, 72, and 46 patients at the initial visit and at 6 months and 1 year after treatment commencement, respectively. Cronbach's alpha was 0.9; test-retest scores were highly correlated (r = 0.9). Patients who were more affected had greater SNOT-20 scores (P < 0.002), and patients who had improved had greater change scores (P < 0.04). Items identified as important had greater scores (P < 0.0001) and showed greater change scores (P < 0.0002). The SNOT-20 is a valid outcome measure for patients with rhinosinusitis; it describes the health burden and is sensitive to clinical change.