Phenotyping of Chronic Obstructive Pulmonary Disease: Current Approaches and Future Directions

Jose      Luis Lopez-Campos

Abstract

The identification of different phenotypes within chronic obstructive pulmonary diseases (COPD) can be important for identifying key mechanisms in the disease process and may help guide treatment plans. The term “phenotype”, first coined by the Danish botanist Wilhelm Johannsen in 1909, is defined as “the observable characteristics of an individual resulting from the interaction of its genotype with the environment”. Numerous prognostic factors have been identified in patients with COPD that might enable classification of such patients into different phenotypes. However, the complex networks of interrelationships between the clinical manifestations of COPD and its prognostic factors make phenotypic classification difficult. Recently, a series of composite multidimensional tools - such as the BODE, SAFE, CPI, and ADO indexes - have been developed to reflect the range of comorbidities and the complexity of underlying mechanisms associated with COPD. Another approach would lie in classification systems based on significant independent prognostic factors identified by multivariable analysis. This approach, however, has thus far failed to produce useful clinical diagnostic tools. Future strategies for phenotyping may include a comprehensive assessment of anatomicalclinical- functional prognostic factors in COPD. Incorporation of these factors may eventually broaden our understanding of COPD pathophysiology and may offer an opportunity to tailor treatment.

Keywords: Chronic obstructive pulmonary disease, phenotypes, prognosis, multidimensional indexes, genotype, prognostic factors, multidimensional tools, chronic bronchitis, emphysema, asthma