In order to contribute to a better clinical characterization of children with severe eosinophilic asthma, the present prospective cohort study was designed to assess the correlation between sputum eosinophils and other biomarkers such as FeNO, blood eosinophil count, and serum periostin levels, as well as to identify prognostic biomarkers of asthma control after 12 months of follow-up. Here, POSTN is linked to asthma.