Prevalence of hypothalamic-pituitary-adrenal axis suppression in children treated for asthma with inhaled corticosteroid

OBJECTIVE: To determine the prevalence of hypothalamic-pituitary-adrenal (HPA) axis suppression in asthmatic children on inhaled corticosteroids (ICS). METHODS: Clinical and demographic variables were recorded on preconstructed, standardized forms. HPA axis suppression was measured by morning serum cortisol levels and confirmed by low-dose adrenocorticotropic hormone stimulation testing. RESULTS: In total, 214 children participated. Twenty children (9.3%, 95% CI 5.3% to 13.4%) had HPA axis suppression. Odds of HPA axis suppression increased with ICS dose (OR 1.005, 95% CI 1.003 to 1.009, P<0.001). All children with HPA axis suppression were on a medium or lower dose of ICS for their age (200 mu g/day to 500 mu g/day). HPA axis suppression was not predicted by drug type, dose duration, concomitant use of long-acting beta-agonist or nasal steroid, or clinical features. CONCLUSION: Laboratory evidence of HPA axis suppression exists in children taking ICS for asthma. Children should be regularly screened for the presence of HPA axis suppression when treated with high-dose ICS (>500 mu g/day). Consideration should be given to screening children on medium-dose ICS.