Validation of the sino-nasal outcome test in Chile

Background: Allergic rhinitis and sinusitis are common diseases that affect quality of life of pediatric and adult patients. Aim: To adapt and validate the Sino-Nasal Outcome Test 20 indicators (SNOT-20) survey in Chilean subjects. Material and Methods: In a psychometric validation study, an adapted version of the SNOT-20 adapted version was applied to 181 volunteers on two different occasions, three weeks apart. Feasibility (response time and perceived difficulty), reliability (internal consistency and test-retest) and validity (concurrent validity, correlating results with an independent instrument; predictive validity assessing its sensitivity to detect changes and discriminant validity, assessing receiver operating characteristic (ROC) curves), were assessed. An exploratory factor analysis was performed to confirm the presence of previously described underlying constructs. Results: Eighty percent of participants considered SNOT-20 easy to complete. This task was completed in less than 5 minutes. Cronbach's alpha was 0.946. Temporal stability on a healthy subgroup was strong with an intraclass correlation coefficient of 0.92. SNOT-20 had a correlation coefficient of 0.82 with an independent instrument and its score significantly decreased after 3 weeks of treatment (p = 0.003). The area under ROC curve was 0.895. Factor analysis identified four principal components which possessed identical structure as previously described. Conclusions: SNOT-20 survey was valid, reliable and easy to implement among Chilean subjects. (Rev Med Chile 2011; 139: 886-895).