Concordance between bronchial hyperresponsiveness, fractional exhaled nitric oxide, and asthma control in children.
BACKGROUND
Previous studies on association between level of asthma control, markers of airway inflammation and the degree of bronchial hyperresponsiveness (BHR) have yielded conflicting results. Our aim was to determine the presence and severity of BHR and the concordance between BHR, asthma control, and fractional exhaled nitric oxide (FeNO) in children with asthma on therapy.


METHODS
In this cross-sectional observational study, children (aged 6-18 years) with asthma on British Thoracic Society (BTS) treatment steps 2 or 3, underwent comprehensive assessment of their asthma control (clinical assessment, spirometry, asthma control test [ACT], Pediatric Asthma Quality of Life Questionnaire [PAQLQ]), measurement of FeNO and BHR (using mannitol dry powder bronchial challenge test [MCT], Aridol™, Pharmaxis, Australia).


RESULTS
Fifty-seven children (63% male) were studied. Twenty-seven children were on BTS treatment step 2 and 30 were on step 3. Overall, 25 out of 57 (43.8%) children had positive MCT. Of note, 9 out of 27 (33.3%) children with clinically controlled asthma had positive MCT. Analyses of pair-wise agreement between MCT (positive or negative), FeNO (>25 or ≤25 ppb) and clinical assessment of asthma control (controlled or partially controlled/uncontrolled) showed poor agreement between these measures.


CONCLUSIONS
A substantial proportion of children with asthma have persistent BHR despite good clinical control. The concordance between clinical assessment of asthma control, BHR and FeNO was observed to be poor. Our findings raise concerns in the context of emerging evidence for the role of bronchoconstriction in inducing epithelial stress that may drive airway remodeling in asthma. Pediatr Pulmonol. 2016;51:1004-1009. © 2016 Wiley Periodicals, Inc.
['Thomas|Biju|B|', 'Chay|Oh Moh|OM|', 'Allen|John C|JC|', 'Chiang|Andrea Shu Xian|AS|', 'Pugalenthi|Arun|A|', 'Goh|Anne|A|', 'Wong|Petrina|P|', 'Teo|Ai Huay|AH|', 'Tan|Soh Gin|SG|', 'Teoh|Oon Hoe|OH|']
D000293:Adolescent D001249:Asthma D001315:Australia D001944:Breath Tests D016535:Bronchial Hyperreactivity D001985:Bronchial Provocation Tests D016084:Bronchoconstriction D002648:Child D003430:Cross-Sectional Studies D045853:Exhalation D005260:Female D006801:Humans D008297:Male D009569:Nitric Oxide D011788:Quality of Life D013147:Spirometry
bronchial hyperresponsiveness asthma asthma control fractional exhaled nitric oxide (FeNO) airway hyperresponsiveness