Asthma phenotypes defined from parameters obtained during recovery from a hospital-treated exacerbation

Publication date: Available online 1 March 2018
Source:The Journal of Allergy and Clinical Immunology: In Practice
Author(s): Rihuang Qiu, Jiaxing Xie, Kian Fan Chung, Naijian Li, Zhaowei Yang, Mengzhang He, Jing Li, Rongchang Chen, Nanshan Zhong, Qingling Zhang
BackgroundAsthma is a heterogeneous disease with diverse clinical manifestations and inflammatory pathologies that is punctuated by exacerbations.ObjectivesTo describe the clinical and inflammatory characteristics of asthma patients treated in hospital for an acute exacerbation.MethodsData from 320 adult patients receiving treatment for an acute exacerbation of asthma were obtained. In 218 with complete data , we used Ward's hierarchical clustering to obtain clusters. Pulmonary function, blood counts, sputum cell counts, serum IgE levels, and fractional exhaled nitric oxide were measured during the hospital admission. We selected 13 variables with which we performed Ward's minimum variance hierarchical clustering.ResultsFour clusters were defined. Clusters 1(24.5%) and 3(36.7%) were characterized by predominantly-female asthmatics with sputum neutrophilia, with Cluster 1 associated with small degree of airflow obstruction and early onset of asthma while Cluster 3 had a moderate degree of reduction in FEV1. Clusters 2(22.0%) and 4(16.5%) were associated with high sputum eosinophilia and severe airflow obstruction, but Cluster 4 was made up exclusively of male smoking subjects while Cluster 2 of predominantly female non-smoking subjects with the worst FEV1, FEF25-75 (% predicted) and arterial partial pressure of oxygen (PaO2) on admission. There were no differences between clusters in terms of atopy, serum IgE, prevalence of nasal disease, maintenance inhaled corticosteroids, or oral/systemic corticosteroid use and asthma exacerbations.ConclusionThe clusters during recovery from an exacerbation of asthma were distinguished by airflow obstruction and a neutrophilic, eosinophilic or mixed inflammation. Eosinophilic inflammation was found in smoking and non-smoking asthmatics during an exacerbation.