Cross-sectional analysis of the Belgian severe asthma registry (BSAR)

The Belgian severe asthma registry (BSAR) is a secured web-based registry encompassing demographic, clinical, functional and inflammatory data of severe adult asthmatics as defined by the ATS, aiming at raising awareness on severe asthma, studying its natural history, identifying phenotypes, and offering tools to optimize care. Methods The cross-sectional analyses of the BSAR included 373 refractory asthmatics from 9 Belgian centers, followed up by respiratory physicians for at least one year. Results Severe asthma was more frequent in women (55%), was associated with atopy (67%) and started early (67% before age of 40). 12% were current smokers and 30% ex-smokers. In addition to high doses of ICS+LABA, 50% of patients received LTRA, 21% anti-IgE and 21% oral corticosteroids. Despite impaired flow rates (mean FEV 1 = 68% pred; FEV 1 /FVC=63%), KCO was well preserved (97% pred). Eosinophilic asthma (sputum Eos≥3%) was the predominant phenotype (55%, n=88) while neutrophilic (sputum Neu≥76%) and paucigranulocytic asthma were 21% and 18% respectively. The median FENO was 26 ppb (4 - 250ppb) and the fraction of patients with FENO≥50ppb was 21% (n=271). Comorbidities included chronic rhinosinusitis (48%), nasal polyposis (16%), oesophageal reflux (35%), overweight and obesity (47%) and depression (19%). Asthma control assessed by ACT and ACQ was impaired (81% had ACT<20 and 91% had ACQ>0.75) and average AQLQ was 4.13. Conclusion In the BSAR, severe asthmatics are characterized by airflow limitation, frequent comorbidities, poor asthma control and quality of life. Paucigranulocytic asthma represents a rare phenotype while uncontrolled eosinophilic airway inflammation was frequently encountered despite normal FENO.