Determining emphysema in adult patients with COPD-bronchiectasis overlap using a novel spirometric parameter: area under the forced expiratory flow-volume loop

Area under flow-volume loop may predict severe exacerbation in COPD patients with high grade of dyspnea

OBJECTIVE

Exacerbations in patients with COPD may still be unpredictable, although the general risk factors have been well defined. We aimed to determine the role of a novel parameter, area under flow-volume loop, in predicting severe exacerbations.

METHODS

In this single-centre retrospective cohort study, 81 COPD patients over 40 years of age with high grade of dyspnea (having a CAT score of ≥10) and a history of ≥1 moderate exacerbation in the previous year were included. Area under flow-volume curve (AreaFE%) was obtained from pulmonary function test graph and calculated from Matlab programme. Univariate and multivariate logistic regression analyses were performed to determine independent risk factors of the severe exacerbation.

RESULTS

Patients with severe exacerbation (n = 70, 86.4 %) were older. They had lower FEV1%, FVC%, 6MWD, AreaFE% and higher CAT score than patients without exacerbation. After performing multivariate analysis, high CAT score and low AreaFE% value were found to be independent risk factors for severe exacerbation (OR: 1.12, 95 % CI: 1.065-1.724; p = 0.01 and OR: 1.18, 95 % CI: 0.732-0.974; p = 0.02).

CONCLUSIONS

We found that a low AreaFE% value was an independent risk factor in addition to a high CAT score and these both have an excellent discriminative ability in predicting the risk of severe exacerbation.

The clinical phenotype of bronchiectasis and its clinical guiding implications

Bronchiectasis is a chronic airway disease with abnormal and persistent bronchial dilatation caused by a variety of reasons. In recent years, numerous reports have shown that bronchiectasis is heterogeneous, the clinical characteristics of patients with different phenotypes are different, and the efficacy of a treatment regimen may vary greatly in patients with different bronchiectasis phenotypes. This paper summarizes the current clinical phenotypic classification of bronchiectasis from the perspective of etiology, microbiology, and the frequency of acute exacerbation, and cluster analysis was used to determine new clinical phenotypes and their statistical and clinical significance. Different tools for assessing disease severity yield different outcomes. This article summarizes the research progress in the above areas, hoping to provide a more comprehensive understanding of the disease.