Validation of the Sino-Nasal Outcome Test 20 (SNOT-20) domains in nonsurgical patients.

BACKGROUND The objectives of this study were, first, to confirm the presence of multiple domains within the Sino-Nasal Outcome Test 20 (SNOT-20) using a medically treated population, and, second, to reanalyze data from this population to reveal incremental information. A prospective, randomized controlled trial was performed. METHODS One hundred twenty-seven adults with chronic rhinitis or rhinosinusitis symptoms were treated with nasal saline irrigation or spray. Treatment outcome was quality of life measured with SNOT-20 scores, which were reanalyzed for this study with a factor analysis. Differences in change scores were compared. RESULTS Factor analysis confirmed the presence of four domains: psychological function, sleep function, rhinological symptoms, and ear and/or facial symptoms. At 8 weeks after randomization, saline irrigation had significant effects on the rhinological symptom (p = 0.01) and sleep (p = 0.01) compared with saline spray, but no between-group difference was seen in psychological function or ear and/or facial symptom domains. CONCLUSION Subscales identified differences in the impact of two medical interventions on chronic sinonasal symptoms. Reporting subscale scores might improve the precision of the SNOT-20 instrument, allowing discrimination between various treatments and their differential impact on sinonasal quality of life.