Standard | Exacerbation | Standard | ||||||||

t | -3 | -2 | -1 | 0 | e_{1} | e_{2} | e_{3} | e_{4} | +1 | +2 |

The baseline measurement was defined as the routine measurement before the clinical onset of an asthma exacerbation, denoted by

*t*=0. The routine measurements before*t*=0 were coded*t*= -1, -2, -3,*etc.*The time interval between these measurements was 2 months. During the exacerbation, measurements were denoted by*t*=e_{1}, e_{2,}e_{3}and e_{4}, referring to the additional measurements at day 1, 3 and 5, and at the end of the event, respectively. After the exacerbation, the standard measurements continued (denoted as t= +1, +2,*etc.*).