Rationale: Mannitol dry powder (MDP) challenge is an indirect bronchial provocation test, which is well studied in adults but not established for children.
Objective: We compared feasibility, validity, and clinical significance of MDP challenge with exercise testing in children in a clinical setting.
Methods: Children aged 6-16 years, referred to two respiratory outpatient clinics for possible asthma diagnosis, underwent standardized exercise testing followed within a week by an MDP challenge (Aridol™, Pharmaxis, Australia). Agreement between the two challenge tests using Cohen's kappa and receiving operating characteristic (ROC) curves was compared.
Results: One hundred eleven children performed both challenge tests. Twelve children were excluded due to exhaustion or insufficient cooperation (11 at the exercise test, 1 at the MDP challenge), leaving 99 children (mean ± SD age 11.5 ± 2.7 years) for analysis. MDP tests were well accepted, with minor side effects and a shorter duration than exercise tests. The MDP challenge was positive in 29 children (29%), the exercise test in 21 (21%). Both tests were concordant in 83 children (84%), with moderate agreement (κ = 0.58, 95% CI 0.39-0.76). Positive and negative predictive values of the MDP challenge for exercise-induced bronchoconstriction were 68% and 89%. The overall ability of MDP challenge to separate children with or without positive exercise tests was good (area under the ROC curve 0.83).
Conclusions: MDP challenge test is feasible in children and is a suitable alternative for bronchial challenge testing in childhood.
Copyright © 2011 Wiley-Liss, Inc.