Objective To determine the reliability, validity, responsiveness, and the minimal important difference (MID) for the Sinonasal Outcome Test-16 (SNOT-16) in the measurement of disease-specific quality of life (QOL) in adults with acute rhinosinusitis.
Study Design Randomized controlled trial to evaluate antibiotic treatment for acute rhinosinusitis.
Setting Ten community practices in St Louis, Missouri.
Methods The modified SNOT-16 was completed at baseline (by both face-to-face and telephone interviews) and by telephone interview at 3, 7, and 10 days by 166 adults with acute rhinosinusitis diagnosed clinically using standardized criteria (36% were male, 78% were white). Considering severity and frequency, patients rated how much they were bothered by each item using a 4-point scale. The mean SNOT-16 score (ranging from 0 [no problem] to 3 [large problem]) was compared with the patients' global assessment of change to evaluate responsiveness and the MID.
Results The instrument was easy to use and took less than 5 minutes to complete. The SNOT-16 score identified statistically significant differences in the hypothesized direction for those reporting more or less severe symptoms (P = .02) and more or less bother (P < .001) demonstrating construct-related validity. The Cronbach α ranged from 0.82 to 0.91, demonstrating high internal consistency. There was a statistically significant decrease in scores with time (multivariate analysis of variance, P < .001). The effect sizes at days 3, 7, and 10 were 1.45, 2.34, and 2.90, respectively, indicating high sensitivity to clinical change. The MID was 0.5 units.
Conclusion The modified SNOT-16 is a valid instrument to assess effectiveness of interventions to improve disease-specific QOL in adults with acute rhinosinusitis.
Trial Registration clinicaltrials.gov Identifier: NCT00377403