Oral steroid-sparing effect of high-dose inhaled corticosteroids in asthma

Background: The proportion of the efficacy of high-dose inhaled corticosteroids (ICS) in oral corticosteroid-dependent asthma that is due to systemic effects is uncertain. This study aimed to estimate the ICS dose-response relationship for oral corticosteroid-sparing effects in oral corticosteroid-dependent asthma, and to determine the proportion of oral corticosteroid-sparing effects due to their systemic effects, based on the comparative dose-response relationship of ICS versus oral corticosteroids on adrenal suppression. Methods: Systematic review and meta-analysis of randomised controlled trials reporting oral corticosteroid-sparing effects of high-dose ICS in oral corticosteroid-dependent asthma. In addition, reports of oral corticosteroid to ICS dose-equivalence in terms of adrenal suppression were retrieved. The primary outcome was the proportion of the oral corticosteroid-sparing effect of ICS that could be attributed to systemic absorption, per 1000 mu g increase of ICS, expressed as a ratio. This ratio estimates the oral corticosteroid sparing effect of ICS due to systemic effects. Results: 11 studies including 1283 participants reporting oral corticosteroid-sparing effects of ICS were identified. The prednisone dose decrease per 1000 mu g increase in ICS varied from 2.1 mg to 4.9 mg, depending on the type of ICS. The ratio of the prednisone-sparing effect due to the systemic effects per 1000 mu g of fluticasone propionate was 1.02 (95% CI 0.68-2.08) and for budesonide was 0.93 (95% CI 0.63-1.89). Conclusion: In patients with oral corticosteroid-dependent asthma, the limited available evidence suggests that the majority of the oral corticosteroid-sparing effect of high-dose ICS is likely to be due to systemic effects.