Background: Increased availability of novel biological therapies for severe asthma has emphasised the need for studies investigating the prevalence of severe asthma. However, currently the prevalence of severe asthma in specialist care is only poorly investigated.
Aim: To describe the prevalence of severe asthma in a real-life population of asthma patients managed in specialist care and to explore the proportion of patients with severe asthma who are eligible for biological therapies with anti-IgE or anti-IL5.
Methods: Patients (≥18 years) with a diagnosis of asthma seen in four respiratory outpatients clinics over a year were screened for having severe asthma according to the ERS/ATS 2014 guidelines. Patients fulfilling the criteria for severe asthma were invited to participate in the SATS study in which the asthma control questionnaire (ACQ), asthma exacerbations, airway inflammation and lung function were investigated systematically.
Results: Among 1034 asthma patients, 16.9% (175 patients) fulfilled the criteria for having severe asthma. In total, 120 patients with severe asthma accepted study inclusion. Among these, 6.7% (8/120) were suitable for anti-IgE treatment due to ACQ≥1.5, ≥2 exacerbations last 12 months, postFEV1<80% and perennial atopy. Furthermore, 13.3% (16/120) were eligible for anti-IL5 treatment based on ACQ≥1.5, ≥2 exacerbations last 12 months and eosinophilic airway inflammation (blood eosinophil count≥0.3x109/L or sputum eosinophils≥3%).
Conclusion: The prevalence of severe asthma in a real-life population of asthma patients managed in specialist care was 16.9%. Among these, 13.3% and 6.7% were eligible for anti-IL5 or anti-IgE therapies, respectively.