Abstract
Introduction. The phenotyping of patients with asthma can help to develop the differentiated approach in treatment.
The aim of the study was to identify and characterize distinct asthma phenotypes.
Methods. Hierarchical cluster analyses (Ward's method) was performed to identify asthma phenotypes in 61 patients with asthma (67% females, age 50,6±11,1 yrs). The demographic and functional parameters and inflammatory markers were assessed in the revealed clusters.
Results. Three clusters were identified based on gender, age of onset, atopy status, frequency of exacerbations and functional parameters. Cluster 1 (n=21) consisted of predominantly females with atopic asthma, onset of disease in middle age (median 41 yrs) and normal lung function. Cluster 2 (n=20) included both males and females, who were mostly atopic with onset asthma in young adult age (median 23,5 yrs), impaired lung function and frequent exacerbations. Patients from cluster 3 (n=20) also demonstrated impaired lung function and frequent exacerbations, but were non-atopic and had middle age onset asthma (median 44,5 yrs). The patients from clusters 2 and 3 tended to have more severe disease, irreversible airway obstruction, lower postbronhodilator FEV1 and higher RV/TLC as compared with cluster 1. Level of serum total IgE and sputum eosinophil count were similar in all clusters, but sputum neutrophil count was higher in clusters 2 and 3. Moreover, the level of IL-1β was higher in cluster 3 as compared with cluster 2.
Conclusion. Identified clinical asthma phenotypes have different underlying pathophysiological mechanisms. Further evaluation of prognostic value of asthma phenotypes may contribute to the development of the differentiated approach in treatment.
- © 2013 ERS
