Etiology of Non-Cystic Fibrosis Bronchiectasis in Adults and Its Correlation to Disease Severity

Rationale: Testing for underlying etiology is a key part of bronchiectasis management, but it is unclear whether the same extent of testing is required across the spectrum of disease severity. Objectives: The aim of the present study was to identify the etiology of bronchiectasis across European cohorts and according to different levels of disease severity. Methods: We conducted an analysis of seven databases of adult outpatients with bronchiectasis prospectively enrolled at the bronchiectasis clinics of university teaching hospitals in Monza, Italy; Dundee and Newcastle, United Kingdom; Leuven, Belgium; Barcelona, Spain; Athens, Greece; and Galway, Ireland. All the patients at every site underwent the same comprehensive diagnostic workup as suggested by the British Thoracic Society. Measurements and Main Results: Among the 1,258 patients enrolled, an etiology of bronchiectasis was determined in 60%, including postinfective (20%), chronic obstructive pulmonary disease related (15%), connective tissue disease related (10%), immunodeficiency related (5.8%), and asthma related (3.3%). An etiology leading to a change in patient's management was identified in 13% of the cases. No significant differences in the etiology of bronchiectasis were present across different levels of disease severity, with the exception of a higher prevalence of chronic obstructive pulmonary disease-related bronchiectasis (P < 0.001) and a lower prevalence of idiopathic bronchiectasis (P = 0.029) in patients with severe disease. Conclusions: Physicians should not be guided by disease severity in suspecting specific etiologies in patients with bronchiectasis, although idiopathic bronchiectasis appears to be less common in patients with the most severe disease.