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What is a clinically meaningful change in exhaled nitric oxide for children with asthma?
Author(s) -
Fielding Shona,
Pijnenburg Marielle,
Jongste Johan,
Pike Katherine,
Roberts Graham,
Petsky Helen,
Chang Anne B.,
Fritsch Maria,
Frischer Thomas,
Szefler Stanley,
Gergen Peter,
Vermeulen Françoise,
Vael Robin,
Turner Steve
Publication year - 2020
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.24630
Subject(s) - interquartile range , exhaled nitric oxide , medicine , asthma , gastroenterology , spirometry
Fractional exhaled nitric oxide (F E NO) may be a useful objective measurement to guide asthma treatment. What remains uncertain is what change in F E NO is clinically significant. Methods An individual patient data analysis was performed using data from seven randomized clinical trials which used F E NO to guide asthma treatment. The absolute and percentage intra‐subject change in F E NO measurements over “stable” and also “unstable” 3‐month periods were described. Results Data were available in 1112 randomized controlled trial participants and ≥1 stable period was present for 665 individuals. The interquartile range (IQR) and limits of agreement (LoA) for change in absolute F E NO among individuals whose initial F E NO was <50 parts per billion (ppb) were −7 to +9 ppb and −43 to +50 ppb, and for those with initial F E NO ≥50 ppb IQR was −29 to +17 ppb and LoA was −80 to +76 ppb. For percentage change in F E NO, the IQR and LoA for individuals whose initial F E NO was <50 ppb were −33% to +51% and −157% to +215%, and for those with initial F E NO ≥50 ppb were −33% to +35% and −159% to +192%. The variation in F E NO values for a stable period was similar irrespective of whether it was followed by a stable or unstable period. Conclusions Over a 3‐month period where F E NO is initially <50 ppb, a rise of <10 ppb or of <50% (based on IQR) is unlikely to be related to asthma. When F E NO is initially ≥50 ppb an percentage change of <50% (based on IQR) is unlikely to be asthma‐related.