Bronchiectasis in Severe Asthma: Does It Make a Difference?

Background: Asthma and bronchiectasis are 2 heterogeneous diseases that frequently coexist, particularly in severe asthma. Recognition of this co-diagnosis may importantly affect treatment decisions and outcome. Previous studies in asthma with bronchiectasis show inconsistent outcomes, probably due to the heterogeneity of the included asthma cohorts. Objectives: We hypothesized that bronchiectasis contributes to asthma severity and that patients with severe asthma and bronchiectasis present with distinct characteristics resulting in different treatable traits. In addition, we explored whether bronchiectasis in severe asthma is more common in a specific phenotype. Methods: This is a single-center study consecutively including patients with severe asthma from a tertiary referral center. Severe asthma was diagnosed according to the ATS/ERS guidelines. Asthma and infectious exacerbations were defined by the attending specialist as respiratory symptoms requiring treatment with systemic steroids or antibiotics, respectively. Two independent blinded radiologists evaluated each CT. Results: 19% of patients with severe asthma showed bronchiectasis on CT. Patients with bronchiectasis had a lower FEV1% predicted (p = 0.02) and FEV1/FVC (p = 0.004) and more infectious exacerbations (p = 0.003) compared to patients without bronchiectasis. Bronchiectasis is more common in patients with a longer duration of asthma, sensitization to A. fumigatus or a positive sputum culture. Sputum cultures of patients with severe asthma and bronchiectasis revealed more P. aeruginosa, S. maltophilia, H. parainfluenzae, and A. fumigates compared to the non-bronchiectasis group. The adult-onset, eosinophilic asthma phenotype showed the highest prevalence of bronchiectasis (29.4%). Conclusions: Patients with severe asthma and coexisting bronchiectasis were found to represent a distinct group, in terms of disease severity, microbiology, and asthma phenotype. Performing (HR)CT and sputum cultures can help to identify these patients. These results can possibly contribute to early recognition and targeted treatment of this patient group.