Table 2.
Classification of Asthma Severity9
| Exacerbations | Intermittent | Mild | Moderate | Severe |
|---|---|---|---|---|
| Symptoms | > 2 d/wk | > 2d/wk but < 1/d | Daily | > 1 daily |
| Nighttime awakenings | < 2×/m | > 2×/m | > 1/wk | Nightly |
| Use of short-acting beta-agonists | < 3 d/wk | ≥ 3 d/wk | Daily | Several times daily |
| Interference with activity | None | Minor limitation | Some limitation | Extremely limited |
| FEV1 | > 80% predicted | > 80% predicted | 60%–80% predicted | < 60% predicted |
| FEV1/FVC ratio | Normal | Normal | Decreased | Decreased |
| Risk | < 2/y | ≥ 2 Exacerbations/y requiring oral or parenteral steroids | ||
Abbreviations: FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity.