Effect of radiological extent and severity of bronchiectasis on pulmonary function

Background: The aim of this study was to ascertain the effect of the extent and severity of bronchiectasis as determined with high-resolution computed tomography (HRCT) on lung function in patients with pure bronchiectasis, bronchiectasis and asthma, and bronchiectasis and chronic obstructive pulmonary disease (COPD). Methods: One hundred nineteen patients (71 with pure bronchiectasis, 25 asthmatic patients with bronchiectasis, and 23 COPD patients with bronchiectasis) underwent HRCT and pulmonary function tests. Computed tomography features were scored by the consensus of 2 radiologists. Results: There were no statistically significant differences among the 3 patient groups regarding the extent of bronchiectasis, bronchial dilatation degree, bronchial wall thickening, decreased attenuation in the lung parenchyma, or presence of mucus in the large and small airways. In the pure bronchiectasis group, a negative correlation was found between forced vital capacity (FVC) % of predicted, forced expiratory volume in 1 sec (FEV1) % of predicted, the FEV1/FVC ratio and the extent of bronchiectasis, bronchial wall thickening, bronchial wall dilatation, and decreased attenuation. At multivariate analysis the main morphologic changes associated with impairment of FVC and FEV1 were the extent of bronchiectasis and a decreased attenuation in the lung parenchyma. The decrease in the FEV1/FVC ratio was associated with bronchial wall dilatation. No correlation was found between morphologic changes and indices of pulmonary function in the asthma and COPD patients. Conclusions: Morphologic changes associated with bronchiectasis do not influence lung function in patients with asthma and COPD directly, although they do play a role in impairing pulmonary function in patients with bronchiectasis alone.