Sample sizes calculations for a new study comparing long-acting β2 agonists plus mandatory inhaled corticosteroids versus ICS alone (adapted from Kazani38)
| Risk difference | Clinical outcomes | Sample size (number of subjects) 1:1 randomisation |
| 0.25×1.000 | 1 excess asthma death | 4384000 |
| 0.25×1.000 | 1 excess asthma death or intubation | 77000 |
| 0.25×1.000 | 5 excess asthma deaths or intubations | 770000 |
| 0.15×1.000 | 5 excess asthma deaths or intubations | 1200000 |