Severe/difficult-to-treat bronchial asthma. Part I: Clinical, demographic and functional characteristics

Introduction. Severe and difficult-to-treat asthma is associated with significant morbidity, lower quality of life and higher health cost for the society. Better understanding of severe/difficult-to-treat asthma phenotype, may help to improve asthma care. Aim of the study. We aimed to distinguish and characterize patients with severe/difficult-to-treat (S/D) bronchial asthma. Material and methods. The study included 210 patients with asthma from one asthma clinic. Following 12 months of observation 109 patients with severe/difficult-to-treat (S/D) asthma defined according to the ATS Workshop 2000 and 101 patients with non-severe (ns mild to moderate) form of the disease were distinguished. After one year of follow up and verification of the diagnosis all patients were skin prick tested and spirometry after nebulization of 2,5 mg of salbutamol was performed. Results. Patients with S/D asthma were significantly older, were more obese and had higher prevalence of hypersensitivity to aspirin. Female gender, obesity, history of aspirin hypersensitivity and history of childhood wheezing were significant risk factors for S/D asthma. The prevalence of atopy was high and similar in both groups (72% and 80% in S/D and nS group respectively). Baseline respiratory function (particularly MEF 25-50%) were significantly lower in patients with S/D asthma, and the degree of reversibility after nebulization of salbutamol was significantly higher in this group. Conclusions. The study documented distinct demographic, clinical and functional characteristics of patients with severe/difficult-to-treat asthma, which may have implications for phenotype specific management.