Evidence for two clusters among non-eosinophilic asthmatics.

BACKGROUND

Although asthma is often seen as an eosinophilic disease associated with atopy non eosinophilic asthmatics represent a substantial part of asthmatic population.

OBJECTIVE

Here we have applied an unsupervised clustering method on a cohort of 588 non eosinophilic asthmatics (sputum eosinophils <3%) recruited from an asthma clinic of a secondary care center.

METHODS

Our cluster analysis of the whole cohort identified two subgroups as cluster 1 (n=417) and cluster 2 (n=171).

RESULTS

Cluster 1 consisted of a dominant female group with a late disease onset, a low proportion of atopy (24%) and a substantial smoking history (53%). In this cluster, treatment burden was low (<50% of ICS users), asthma control and quality of life was poor with median ACT, ACQ and AQLQ of 16 and 1,7 and 4,5 respectively whereas lung function was preserved with a median post bronchodilation FEV1 of 93% predicted. Cluster 2 was a dominant male group, almost exclusively composed of atopic patients (99%) with early disease onset and a moderate treatment burden (median ICS dose 800 µg/d equivalent beclomethasone). In cluster 2 asthma was partially controlled with median ACT and ACQ reaching 18 and 1.3 respectively and lung function well preserved with a median post bronchodilation 95% predicted. While systemic and airway neutrophilic inflammation was the dominant pattern in cluster 1, cluster 2 essentially comprised paucigranulocytic asthma with moderately elevated FeNO.

CONCLUSION

Non eosinophilic asthma splits in two clusters distinguishing by disease onset, atopic status, smoking history, systemic and airway inflammation and disease control and quality of life.

Informations de copyright

Copyright © 2024. Published by Elsevier Inc.

Déclaration de conflit d'intérêts

Declaration of competing interest R. Louis reports an educational grant and lecture fees from GSK, a research grant and advisory board fees from AZ, a research grant from Chiesi and a research grant and advisory board fees from Novartis, outside the submitted work. F. Schleich reports lecture and advisory board fees from GSK, AZ, Chiesi and Novartis, outside the submitted work.