BACKGROUND: Chronic rhinosinusitis (CRS) is becoming increasingly prevalent in 
adults with cystic fibrosis (CF), as the median age of survival rises for these 
individuals. Delayed identification of CRS may contribute to worsening 
health-related quality of life and increased treatment burden. Our objective was 
to investigate the utility of the 22-item Sino-Nasal Outcome Test (SNOT-22) as a 
tool to identify CRS in adults with CF.
METHODS: In this cross-sectional study, participants were sampled from an 
adult-specific CF clinic in Vancouver, Canada, between September 2013 and April 
2014. CRS was determined by use of standardized diagnostic guidelines. 
Participants completed the SNOT-22 and medical charts were reviewed for 
additional predictor variables. Logistic regression was used to compare the 
SNOT-22 as a univariable predictor variable to a multivariable prediction model, 
in order to best differentiate CRS and non-CRS participants.
RESULTS: Ninety-three of 101 adults provided written informed consent. The 
prevalence of CRS was 56.3% (95% confidence interval [CI], 45.9% to 66.3%). 
Individuals with CRS reported significantly higher SNOT-22 scores than non-CRS 
participants (mean difference: 13.9; 95% CI, 6.1 to 21.7). The optimal SNOT-22 
score to differentiate CRS was 21 out of 110 (sensitivity: 76%, specificity: 
61%, positive predictive value: 71%, likelihood ratio: 1.9).
CONCLUSION: Compared to the current diagnostic gold standard, SNOT-22 scores 
greater than 21 sufficiently identified adults with CF presenting with 
concomitant CRS. The SNOT-22 is a simple instrument that can easily be 
implemented in adult CF clinics to assist care providers identify individuals 
requiring more detailed assessment or referral to a sinus clinic.