Metabolomic differences of exhaled breath condensate among children with and without asthma

Abstract Background There remains an unmet need in objective tests for diagnosing asthma in children. The objective of this study was to investigate the potential of metabolomic profiles of exhaled breath condensate (EBC) to discriminate stable asthma in Asian children in the community. Methods One hundred and sixty‐five Asian children (92 stable asthma and 73 non‐asthmatic controls) participating in a population‐based cohort were enrolled and divided into training and validation sets. Nuclear magnetic resonance‐based metabolomic profiles of EBC samples were analyzed by using orthogonal partial least squares discriminant analysis. Results EBC metabolomic signature (lactate, formate, butyrate, and isobutyrate) had an area under the receiver operator characteristic curve (AUC) of 0.826 in discriminating children with and without asthma in the training set, which significantly outperformed FeNO (AUC = 0.574; P < .001) and FEV 1 /FVC % predicted (AUC = 0.569; P < .001). The AUC for EBC metabolomic signature was 0.745 in the validation set, which was slightly but not significantly lower than in the testing set ( P = .282). We further extrapolated two potentially involved metabolic pathways, including pyruvate ( P = 1.67 × 10 −3 ; impact: 0.14) and methane ( P = 1.89 × 10 −3 ; impact: 0.15), as the most likely divergent metabolisms between children with and without asthma. Conclusion This study provided evidence supporting the role of EBC metabolomic signature to discriminate stable asthma in Asian children in the community, with a discriminative property outperforming conventional clinical tests such as FeNO or spirometry.