Dissociation of lung function, dyspnea ratings and pulmonary extension in bronchiectasis

Bronchiectasis is a heterogeneous disease in terms of its clinical and functional presentation. Some isolated parameters have been used to assess the severity of bronchiectasis or its response to treatment. A study was undertaken to evaluate whether lung function, dyspnea and extension of the disease are separate entities in the impact of bronchiectasis upon patients using factor analysis. Patients with bronchiectasis diagnosed by high-resolution computed tomography (HRCT) and airflow obstruction defined by FEV1/FVC<70% were included. Data were collected relating to clinical history, three different clinical ratings of dyspnea (Medical Research Council (MRC), Borg scale and Basal Dyspnea Index), the extent of bronchiectasis and functional variables. A total of 81 patients (mean age (SD): 69.5 (8.7)) years were included. The degree of dyspnea (MRC) was 1.9 (0.8). Mean FEV1 was 1301 ml (56.9% pred.). Four factors were found that accounted for 84.1% of the total data variance. Factor 1 (45.6% of the data variance) included the three measurements of dyspnea. Factor 2 (16% variance) comprised airflow obstruction parameters (FEV1, FEV1/FVC and PEF). Factor 3 (13.8% variance) included RV/TLC and RV (lung hyperinflation). Factor 4 (8.6% variance) included bronchiectasis extent. Dyspnea was more closely correlated with lung hyperinflation (r:0.33-0.54) than with airflow obstruction parameters (r:0.17-0.26).

Airflow obstruction, dyspnea, lung hyperinflation and the lung extent of the bronchiectasis are four independent entities in the impact of bronchiectasis upon patients.