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High fractional exhaled nitric oxide levels in asthma patients: Does size matter?
Author(s) -
Diamant Nir,
Amirav Israel,
ArmoniDomany Keren,
Sadot Efraim,
Shapira Udi,
Cahal Michal,
Be'er Moria,
Rochman Mika,
Lavie Moran
Publication year - 2021
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.25333
Subject(s) - medicine , exhaled nitric oxide , asthma , biomarker , comorbidity , spirometry , airway , interquartile range , gastroenterology , anesthesia , biochemistry , chemistry
Background Fractional exhaled nitric oxide (FeNO) is a biomarker for eosinophilic inflammation used for diagnosis and monitoring of asthma. High FeNO indicates significant airway eosinophilia and steroid‐responsive airway inflammation. Some children with asthma have extremely high FeNO levels, but whether these levels represent a different asthma phenotype compared with those with mildly elevated FeNO is unclear. The objective of this study is to investigate whether the extent of high FeNO levels correlates with clinical phenotype, asthma control, comorbidity, and pulmonary function test (PFT) findings in children with asthma. Methods Anthropometric data, daytime and nighttime symptoms, controller treatment, comorbidity, and PFT findings were retrieved from the Pediatric Pulmonology Unit database (2014–2020) and correlated with FeNO levels in pediatric asthma patients with high FeNO levels. Results Two‐hundred children and adolescents with high FeNO levels (range 36–227 ppb) were included. Within this range, higher FeNO levels positively correlated with increased daytime and nighttime symptoms ( p = .013 and p = .01, respectively) and poorly controlled asthma ( p = .034). A FeNO level of ≥80 ppb was the cutoff for significantly more severe daytime and nighttime symptoms and very poorly controlled asthma compared with levels <80 ppb ( p = .004, p = .005, and p = .036, respectively). No correlation was found between FeNO and controller treatment, comorbidity, and PFT performance. Conclusion In pediatric asthma patients, high FeNO levels correlate with increased symptom severity and poor asthma control. A FeNO level of ≥80 ppb may serve as an objective indicator for severe asthma.