Use of the modified SNOT-16 in primary care patients with clinically diagnosed acute rhinosinusitis

Abstract

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.