Table 2 GRADE assessment of the included studies
Number of studies | Certainty assessment | Certainty | Importance | |||||
|---|---|---|---|---|---|---|---|---|
Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | |||
Exacerbation | ||||||||
 5 | Observational studies | Not serious | Not serious | Not serious | Not serious | None |
HIGH | CRITICAL |
Risk (Categorical) | ||||||||
 2 | Observational studies | Not serious | Not serious | Not serious | Not serious | None |
LOW | CRITICAL |
Time to first severe exacerbation | ||||||||
 1 | Observational studies | Not serious | Not serious | Not serious | Not serious | Publication bias strongly suspected dose response curvea |
HIGH | CRITICAL |
Asthma admissions | ||||||||
 1 | Observational studies | Not serious | Not serious | Not serious | Not serious | None |
HIGH | IMPORTANT |
Relapse | ||||||||
 1 | Observational studies | Not serious | Not serious | Not serious | Not serious | None |
HIGH | IMPORTANT |
