Chronic obstructive pulmonary disease subpopulations and phenotyping

Abstract

The diagnosis and treatment of chronic obstructive pulmonary disease (COPD) has been based largely on a one-size-fits-all approach. Diagnosis of COPD is based on meeting the physiologic criteria of fixed obstruction in forced expiratory flows and treatment focus on symptomatic relief, with limited effect on overall prognosis. However, patients with COPD have distinct features that determine very different evolutions of the disease. In this review we highlight distinct subgroups of COPD characterized by unique pathophysiologic derangements, response to treatment, and disease progression. It is likely that identification of subgroups of COPD will lead to discovery of much needed disease-modifying therapeutic approaches. We argue that a precision approach that integrates multiple dimensions (clinical, physiologic, imaging, and endotyping) is needed to move the field forward in the treatment of this disease.

Keywords: Chronic bronchitis; asthma; chronic obstructive pulmonary disease; computed tomographic scan; emphysema; exacerbation; inflammation; microbiome.

Fig 1

Schematic representation of COPD assessment dimensions. Circles represent dimensions enclosing variables with defined or possible relevance to diagnosis, prognosis, or potential therapy in patients with COPD. Colors used to fill circles illustrate the degree of knowledge, validation, and acceptance for the variables in these dimensions. Stratification and prognostication have been based largely on variables contained within the clinical and physiologic dimension in which more needs to be explored in the imaging and endotyping dimension. ADO, Age, dyspnea, and airflow obstruction; BMI, body mass index; BODE, body mass index, airflow obstruction, dyspnea, and exercise capacity; DLCO, diffusing capacity of the lungs for carbon monoxide; DOSE, dyspnea, airflow obstruction, smoking, and exacerbation; Fot, forced oscillation technique; Hx, history; IOS, impulse oscillometry; MRI, magnetic resonance imaging; RV, rhinovirus; SGRQ, St George Respiratory Questionnaire; TLC, total lung capacity.

Fig 2

Taxonomy of COPD. On the basis of a model of the tree of life used to annotate living organisms, we represented our conceptualization of how subpopulations of COPD might be related but differentiated. In this review we proposed the need to define subpopulations of COPD that can share common variables (eg, physiologic and clinical variables) but that also had distinct features (eg, defined airway/parenchymal abnormalities, specific inflammatory pathways, and/or dysbiotic microbiota) that lead to a different natural history of disease and potential therapeutic targets.