Evaluation of association between exercise-induced bronchoconstriction and childhood asthma control test...

Asthma control represents a major challenge in the management of asthmatic children; however, correct perception of control is poor. The aim of the study was to evaluate the association between subjective answers given to the Childhood Asthma Control Test (C-ACT) and objective evaluation of exercise-induced bronchonstriction (EIB) by standardized treadmill exercise challenge.

EIB was evaluated by standardized treadmill exercise challenge and related to C-ACT scores in 92 asthmatic children.

Of the 92 studied children only six children had a concordance between a positive challenge test (ΔFEV1 ≥ 13%) and a positive response to the exercise-related issue of the C-ACT questionnaire (C-ACT total score ≤ 19). There was no significant association between the degree of EIB and the scores relative to the single question on exercise-related problems while a significant association was found when considering the whole questionnaire with C-ACT total score > 19 (r = -0.40, P < 0.001). The two single questions showing a significant association were those focusing on nocturnal asthma. The areas under the ROC curve (AUC) for the sum of the scores of these questions in relationship to a positive response to the exercise test was 0.74. The AUC of the C-ACT total score was 0.76 and 0.55 for the specific question on EIB related problems.

The discrimination power of the C-ACT total score in relationship to EIB was moderately good, and C-ACT questionnaire was capable of correctly predicting the absence of EIB in children reporting a global score > 19. However, direct questions on EIB are associated with a high number of false positive and negative responses; better associations are found questioning on the presence on nocturnal symptoms.