PUB - Publikationen an der Universität Bielefeld

Background: Bronchodilator reversibility is a diagnostic criterion for asthma. However, patients with asthma may exhibit irreversible obstruction eg due to long-standing uncontrolled disease with airway remodeling or beta-2 receptor down-regulation. Aim: This study aims to describe frequency of negative bronchodilator reversibility in patients with severe asthma and associations with other phenotypic characteristics. Methods: Bronchodilator testing was performed according to guideline recommendations, with patients being advised to pause interfering treatments before testing. Significant bronchodilator reversibility was defined as FEV1 increase > 200ml AND > 12% upon SABA inhalation. Results: Bronchodilator reversibility results were available from 793/ 2013 patients included in the registry. Hereof, 250 (31.5%) had significant reversibility, while 543 (68.5%) were classified irreversible. Comparing patients with reversible and irreversible obstruction, sex (52% vs 56%), mean age (49.6 vs 50.0 years), smoking history (non: 57.2% vs 56.1%; active: 2.8% vs 2.2%; ex: 40% vs 41.7%), COPD comorbidity (5.2% vs 7.2%) and BMI (27.2 vs 27.5kg/m2) were similar in both groups. Comorbidities significantly associated with irreversible obstruction were GERD and EGPA(p<0.05). Patients with positive BDR reported dyspnea at rest (27% vs 16%) and chest tightness (36% vs 26%) more frequently, had more severe obstruction at baseline (FEV1: 56% pred. vs. 64% pred.) and higher median FeNO levels (41ppb vs 33ppb). Conclusion: The majority of patients had negative BDR test and this was associated with lower FeNO levels and history of GERD and EGPA.