Evidence Level B
Randomized controlled trials (RCTs) of <200 participants, methodologically flawed RCTs of >200 participants, methodologically flawed systematic reviews (SRs) or good quality observational (cohort) studies.
Symptom severity: there is medium-quality evidence that low-dose inhaled corticosteroids are more effective than placebo at improving symptoms and at reducing the need for short-acting bronchodilators in people with mild, moderate, or severe asthma. Low-dose inhaled corticosteroids are also more effective than placebo at improving lung function (FEV1 and peak expiratory flow rate [PEFR]) in people with asthma.
More info from BMJ Clinical Evidence
