Proportion of subjects with severe asthma experiencing an exacerbation
| Placebo | Azithromycin | p-value | |
| Asthma GINA step 4 | 109/170 (64.1%) | 80/174 (46.0%) | 0.001 |
| ISAR# | 112/175 (64.0%) | 84/182 (46.2%) | 0.001 |
| Severe asthma (ATS/ERS)¶ | 62/96 (64.6%) | 56/115 (48.7%) | 0.021 |
GINA: Global Initiative for Asthma; ISAR: International Severe Asthma Registy. #: asthma GINA step 4 and 5; ¶: American Thoracic Society/European Respiratory Society.