First author [ref.] | Severity | Definition |
Dombrowski [13] | Mild | Asthma symptoms in the previous 6 months |
Asthma symptoms <8 days in the previous 4 weeks | ||
FEV1 ≥80% pred | ||
Not taking daily asthma medication | ||
Moderate/severe | Asthma symptoms on ≥8 days during the previous 4 weeks not attributable to a URI | |
FEV1 <60–79% pred | ||
Use of one or more daily medications which may include OCS in severe asthmatics | ||
Kallen [21] | Mild | 1 asthma drug |
Moderate/severe | ≥2 asthma drugs | |
Firoozi [22, 23] | Asthma severity index | |
Mild | ICS 0–500 g·day−1 and no additional controller therapy or 0–250 μg·day−1 and additional controller therapy | |
No moderate-to-severe asthma exacerbation | ||
No more than three doses of SABA over a 12-month period | ||
Moderate | ICS >500 μg·day−1 with no additional controller therapy or doses >250 μg·day−1 for those receiving additional controller therapy or more than four doses SABA per week over a 12-month period and moderate-to-severe exacerbation | |
Severe | ICS >1000 μg·day−1 or >10 doses SABA per week and moderate-to-severe exacerbation |
FEV1: forced expiratory volume in 1 s; % pred: % predicted; URI: upper respiratory infection; OCS: oral corticosteroids; ICS: inhaled corticosteroid; SABA: short-acting β-agonist.