Stability of severe asthma phenotypes

Introduction . Severe asthma (SA) is a heterogeneous disease with several phenotypes. There are lack of data about its stability. Aim . To assess stability of SA phenotypes in adult patients during 5 years follow-up. Materials and methods . Prospective study included 117 adult outpatients with allergic SA, 51 severe asthmatics with aspirin- induced disease, 59 patient with persistent airflow limitation (PAL) and 35 patients with SA and concomitant COPD, 65 steroid-dependent severe asthmatics and 89 patients with SA and frequent (>2 per year) exacerbations. Spirometry and bronchodilator reversibility testing were carried out; fractional exhaled nitric oxide (FeNO) was measured; hypersensitivity to common inhalant allergens (skin prick and blood specific IgE testing) and peripheral blood eosinophil counts were estimated. Asthma control and asthma-related quality of life were assessed by using ACQ-5 and SGRQ questionnaire. Results . During 5-year prospective study stability of aspirin-induced SA and SA with COPD was 100%. Allergic phenotype was stable in 81% of SA cases and in patients with changed atopic status we revealed worsening of symptoms and accelerated lung function decline. Stability of SA phenotype with PAL without COPD was 86% and steroid-dependent SA was stable in 55% of cases. After 5 years of treatment frequent exacerbations remained in 28% of severe asthmatics. Conclusion . The most stable phenotypes of SA were aspirin-induced and asthma with concomitant COPD. Less stable were allergic SA, steroid-dependent SA and phenotype with persistent airflow limitation. The least stable was SA phenotype with frequent exacerbations.