Inclusion Criteria

Inclusion Criteria

• According to 2018 definitions of Global Initiative for Asthma (GINA) Step 5 treatment; or

• GINA Step 4 treatment and uncontrolled asthma (as outlined by American Thoracic Society/European Respiratory Society guidelines below:)

1. Poor symptom control: ACQ > 1.5, ACT <20 (or ‘‘not well controlled’’ by National Asthma Education and Prevention Program/GINA guidelines)
2. Frequent severe exacerbations: two or more bursts of systemic CS (>3 days each) in the previous year
3. Serious exacerbations: at least one hospitalisation, ICU stay or mechanical ventilation in the previous year
4. Airflow limitation: after appropriate bronchodilator withhold FEV1 <80% predicted (in the face of reduced FEV1/FVC defined as less than the lower limit of normal)