The Heterogeneity in COPD Phenotypes

Chronic obstructive pulmonary disease (COPD) is physiologically characterized by airflow limitation, but the clinical manifestations are heterogeneous. While cigarette smoke is a main cause of COPD, not all smokers develop COPD. Some smokers develop the disease at a younger age, termed early COPD, but others develop it at an older age. Moreover, in addition to a rapid decline in lung function after adulthood, abnormal lung growth with a subsequent normal decline in lung function is also a cause of COPD. From a structural perspective, airway disease dominant and emphysema dominant COPD have distinct clinical features, but recent studies suggest that bronchiectasis and incidental fibrotic change also affect clinical outcomes in COPD. We should also pay attention to concomitant asthma and a prior history of asthma because asthmatic components are commonly found in a subgroup of COPD and determine a distinct clinical phenotype. Collectively, the importance of the establishment of relevant phenotypes with distinct outcomes and responses to various interventions and outcomes is increasingly recognized to perform personalized management of COPD. Previous studies have attempted to establish phenotypes, but the complex features in COPD remain not fully described with currently-proposed phenotypes. 

The aim of this Research Topic is to discover novel factors associated with the heterogeneous clinical outcomes in COPD, to characterize potential COPD phenotypes by comparing clinical outcomes between distinct phenotypes, for examples, early COPD and late-onset COPD, COPD with and without asthmatic components, COPD with and without bronchiectasis, and so on, to establish novel methods to evaluate the heterogeneity in COPD phenotypes, such as imaging (CT, MRI), pulmonary function tests (Spirometry, Oscillation), blood and sputum biomarkers, and cutting-edge computer-based models such as deep learning, and characterize non-COPD subjects who carry a higher risk of future COPD. 

We believe that these comprehensive approaches from multiple articles would increase understanding of the heterogeneity in COPD phenotypes and help to provide personalized medicines in each patient. We are interested in receiving manuscript covering, but not limited to, the following themes:

Early COPD.

Abnormal lung growth and COPD development.

Lung imaging to define clinical phenotypes.

Pathology of COPD phenotypes.

Intrapulmonary and extrapulmonary comorbidity in COPD including asthma, bronchiectasis, lung fibrosis, muscle loss, osteoporosis, and pulmonary hypertension.

A risk of exacerbations and relevant biomarkers.

Non-COPD with lung abnormalities such as emphysema and airway disease.