Clinical asthma phenotyping: A trial for bridging gaps in asthma management

Abstract

Asthma is a common disease affecting millions of people worldwide and exerting an enormous strain on health resources in many countries. Evidence is increasing that asthma is unlikely to be a single disease but rather a series of complex, overlapping individual diseases or phenotypes, each defined by its unique interaction between genetic and environmental factors. Asthma phenotypes were initially focused on combinations of clinical characteristics, but they are now evolving to link pathophysiological mechanism to subtypes of asthma. Better characterization of those phenotypes is expected to be most useful for allocating asthma therapies. This article reviews different published researches in terms of unbiased approaches to phenotype asthma and emphasizes how the phenotyping exercise is an important step towards proper asthma treatment. It is structured into three sections; the heterogeneity of asthma, the impact of asthma heterogeneity on asthma management and different trials for phenotyping asthma.

Keywords: Asthma phenotypes; Asthma heterogenity; Endotypes; Asthma subtypes; Asthma syndrome

Core tip: Although asthma diagnosis is based mainly on clinical basis using history taking and physical examination, treatment options are not tailored according to the clinical phenotype. We still do not have a way to work up a given patient with asthma and to easily delineate the specific pathobiology that leads to her or his airway dysfunction. We can recognize the clinical syndromes, but we cannot spell out the steps that lead from genetic or biochemical defects to disease presentation. Thus we are left with a paradox in the study of asthma; we have effective treatments that are not biologically informative, and we have informative treatments that are less effective.