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.
Keywords: airway hyperresponsiveness, children,
FEF75, methacholine challenge, nocturnal cough,
predictive score, tree pollen allergy,