Bronchodilator response as an independent predictor of severity in bronchiectasis

Bronchodilator response (BDR) is occasionally observed in patients with bronchiectasis. However, clinical implications of BDR of bronchiectasis remain unclear. This multicenter observational cohort study aimed to compare clinical characteristics and severity in bronchiectasis between patients with BDR and without BDR.

We collected data from the Korean Multicenter Bronchiectasis Audit and Research Collaboration (KMBARC) registry, a multicenter observational cohort of non-cystic fibrosis bronchiectasis. We reviewed the medical records of 709 patients who underwent spirometry. We defined BDR as forced expiratory volume in one second (FEV₁) or forced vital capacity (FVC) improvement from pre-bronchodilator value by at least 200 mL and 12% for baseline or 1-year follow-up spirometry.

Of the 709 patients, 7.3% exhibited BDR. Patients with BDR showed worse pulmonary function than those without BDR, both at baseline (FEV₁%, 52.7% vs. 65.3%) and at 1-year follow-up spirometry (52.2% vs. 62.9%). Inhaled corticosteroid (ICS)-containing agents were more frequently used in patients with BDR than those without BDR. Patients with BDR showed higher rates of emergency room visits (15.4% vs. 6.7%) and hospitalization (30.8% vs. 16.6%) than those without BDR. When measuring bronchiectasis severity with Bronchiectasis Severity Index, FACED [F: FEV₁; A: age; C: chronic colonization by Pseudomonas aeruginosa, E: radiological extension (number of pulmonary lobes affected), and D: dyspnea], and E-FACED (FACED plus exacerbations) scores, patients with BDR showed more severe bronchiectasis status than those without BDR.

In bronchiectasis, BDR is associated with poorer lung function, more frequent exacerbation, and increased disease severity.