Background: CF is an important cause of bronchiectasis (BE) with specific highly effective modulator treatments available for the majority of patients. Patients with CF may not be detected by screening and may therefore present for the first time in adult non-CF BE clinics.  

Aim: To describe the frequency of testing for CF within European non-CF BE clinics.

Methods: EMBARC is a prospective observational registry of patients with CT confirmed BE from 31 countries. Data on CF testing by sweat test and CF genetics were recorded if they were performed at any time prior to the baseline visit. Patients with a diagnosis of CF were not included. A multiple logistic regression model was used to identify independent predictors of being tested for CF.

Results: Among 19,324 patients, 1,749 underwent sweat tests: 1,512 negative, 216 intermediate, and 21 positive for potential CF. Genetic testing in 1,213 patients revealed CFTR mutations in 121 cases. Factors influencing testing included younger age (OR 0.96, 95% CI 0.95-0.96, p < 0.001), longer diagnosis duration (p < 0.0001), presence of P. aeruginosa (OR 1.35, 95% CI 1.18-1.54, p < 0.0001) and S. aureus (OR 1.25, 95% CI 1.04-1.50, p = 0.02), poorer lung function (p < 0.0001), nasal polyposis, rhinosinusitis (OR 1.67, 95% CI 1.48-1.88, p < 0.0001), and severe radiological findings. Conversely, patients with asthma and COPD were less likely to be tested. Testing rates were highest in Northern and Western Europe (23.6%) and Southern Europe (16.3%), lowest in Eastern Europe.

Conclusion: The findings underscore a significant proportion of adult BE patients remaining untested for CF.