Review of the effect of the dosing interval for inhaled corticosteroids in asthma control

Background: Asthma is recognized as an inflammatory disease of the airways and treatment includes anti-inflammatory agents such as corticosteroids. Inhaled corticosteroids (ICS) are widely prescribed for long-term prophylaxis, yet their optimal dosing interval is not clear. Aims: To determine whether the dosing interval of ICS affects asthma control. Methods: We performed an electronic search of the literature to identify studies on the dosing interval of ICS in asthmatic subjects. Data were extracted from suitable studies by two independent researchers and, where possible, a meta-analysis performed. Results: A total of 4267 titles were retrieved, of which 13 met inclusion and exclusion criteria and 11 had extractable data. There were no significant differences between outcomes for: (i) once daily vs twice daily administration (7 trials, 810 subjects), (ii) once daily vs four times daily administration (2 trials, 68 subjects) and (iii) twice daily vs four times daily administration (4 studies, 111 subjects). There was a variety of outcomes used to assess differences between dosing intervals. These included symptom scores, lung function, use of rescue medication and adverse drug effects. The number of subjects that could be included in the statistical analysis of any of such outcomes was small, much smaller than the total sample size. Conclusions: There was no significant difference in measures of asthma control between the assessed dosing intervals of ICS. Current evidence indicates that single daily administration of ICS produces equivalent asthma control to multiple daily administration.