MetabolomicDifferences of Exhaled Breath Condensate AmongChildren With and WithoutAsthma.

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 sixty-fiveAsian 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<0.001) and FEV1 /FVC % predicted (AUC = 0.569; P<0.001). 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 = 0.282).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 metabolomicsignature to discriminate stable asthma in Asian children in the community, with a discriminative property outperforming conventional clinical tests such asFeNOor spirometry.