Abstract
Patients with severe refractory asthma often need regular oral corticosteroid (CS) therapy in addition to inhaled CS. We determined whether CS-dependent subjects are a distinct group by comparing their clinical features and inflammatory biomarkers to those of non-CS-dependent subjects. The severe asthma UBIOPRED cohort consisted of 372 patients, with 44% classified as CS-dependent. Severe asthma was defined according to the IMI-criteria (Bel et al. Thorax 2011; 66: 910-7).
There was a similar female preponderance and BMI in both groups, but the CS-dependent group had greater exacerbation rate (3 vs 2/year; p=0.001), prevalence of nasal polyps (48% vs 23%; p=0.0003) and GINA severity score (p=0.01), associated with greater use of nebulised bronchodilators and theophylline. They also had lower pre-bronchodilator FEV1 (63.1% vs 66.4%; p<0.05). Blood neutrophil count was higher but eosinophils were lower. In induced sputum, eosinophils were non-significantly increased (5.2% vs 2.0%; p=0.063), but sputum macrophages were lower (13.9% vs 27.8%; p=0.01). There was an increase in the mixed granulocytic profile in sputum (26 vs 8%) and a reduction in the paucigranulocytic profile (10% vs 31%). In blood, neutrophil counts increased while eosinophils decreased, indicating a systemic effect of CS. FENO was higher (30 vs 22 ppb; p=0.001).
This preliminary analysis indicates that CS-dependent severe asthma represents a more severe group with higher inflammatory biomarkers with lesser sensitivity to CS beneficial effects, characterised by an eosinophilic and neutrophilic sputum profile. Further -omics analysis in progress will provide a more precise delineation of this phenotype.
- © 2014 ERS