Novel predictors of airway hyperresponsiveness in children with
respiratory symptoms without obstructive pattern
Abstract
Background: Methacholine challenge (MCC) is the most common method to
detect airway hyperresponsiveness (AHR). Although MCC is accepted as
safe diagnostic tool, it is time consuming and could be exhausting for
patients. Thus, it might be helpful to identify predictive factors for
AHR. We aimed to develop a diagnostic tool for predicting AHR in
children with respiratory symptoms without obstructive pattern. Methods:
Data from children who had undergone MCC were analyzed retrospectively.
The demographic features of patients along with laboratory results were
collected. Results: A total of 123 children with a median age of 10.5
years were enrolled. AHR was detected in 81 children (65.8%). The age
of the children with AHR was significantly younger. The prevalences of
aeroallergen sensitization, nocturnal cough, wheezing and a baseline
forced expiratory flow at 75% of vital capacity (FEF75) <65%
were significantly more frequent in children with AHR. Multivariate
logistic regression analysis revealed age, ever wheezing, nocturnal
cough, tree pollen allergy and FEF75<65% as independent
predictors of the AHR. A weighted clinical risk score was developed
(range, 0-75 points). At a cutoff point of 35 the presence of AHR is
predicted with a specificity of 90.5% and a positive predictive value
(PPV) of 91.5%. Conclusion: In children suspected of having asthma, but
without an obstructive pattern, combining independent predictors, which
can be easily obtained in clinical practice, in a novel prediction rule
might be used to identify children with AHR.