D3.123 - The complementary role of impulse oscillometry in prediction of asthma persistance at school age among preschool children with recurrent wheezing

Some clinical predictive models that can estimate asthma risk at school age have been developed for preschool children with recurrent wheezing but the role of early lung function testing is uncertain. Impulse oscillometry (IOS), which can reveal airway dysfunction in small children, can be a valuable predictive tool. The aim of this study is to evaluate the value of preschool IOS parameters for predicting asthma at school age in children with recurrent wheezing episodes.

Preschool children who had been admitted with recurrent wheezing and followed-up until school age at a pediatric allergy outpatient clinics were recruited. Demographic and clinical features, laboratory tests and IOS performed at admission were retrieved from medical records.  The results of these variables were compared between children with persistant asthma diagnosis at school age (group SA) and children who recovered from wheezy disease before school age (group NA). A multivariant linear regression analysis was performed in order to evaluate the importance of variables in predicting asthma at school age.

Among recruited wheezy preschool children, 87 (group SA) cases were diagnosed as persistent asthma with clinical and spirometry findings at school age. Preschool IOS recordings revealed that parameters reflecting small airway involvement (Resistance at 5Hz(R5Hz) Z-score and R5Hz-R20Hz/R20Hz ratio) and distinctive bronchodilator response at R5Hz and area of reactance (AX) were significantly different between children in group SA and NA (p< 0.001). Multivariant regression analysis which included all significant clinical and laboratory variables and also IOS results, showed that a high “R5Hz Z-score” and an elevated “(R5Hz-R20Hz)/R20Hz” ratio significantly increased the risk of asthma diagnosis at school age, independent from family atopy, food and inhalant allergen sensitizations and steroid use. A ROC analysis was performed for finding the optimal cut-off values for a significant bronchodilator response in R5Hz and AX parameters that can predict school age asthma persistance. These values were a 28,14 % decrease in R5Hz (AUC = 0,715; sensitivity=43,68; specifity= 96,5; p < 0,001) and a 39,03 % decrease in AX (AUC = 0,664; sensitivity=70,11; spesifity=57,5); p < 0,001).

IOS measurements at preschool age children  with recurrent wheezing can aid in prediction of asthma at school age .