Relationship between sputum eosinophils and lung function, fractional exhaled nitric oxide concentration in children with bronchial asthma

Objective To explore the relationship between sputum eosinophils count (EOS) and lung function, fractional exhaled nitric oxide (FeNO) concentration in children with bronchial asthma (asthma). Methods A total of 113 children with asthma in Hainan Women and Children′s Medical Center from October 2016 to December 2018 was retrospectively enrolled in the observation group.Meanwhile, 50 healthy children who had physical examination in Hainan Women and Children′s Medical Center in the same period were assigned into the control group.The induced sputum EOS, forced expiratory volume in one second as a percentage of expected value (FEV1%pred) and FeNO levels of two groups were detected and analyzed. Results The level of induced sputum EOS and FeNO in the observation group was significantly higher than that of in the control group (t=11.921, 17.081, both P<0.05). And the FEV1%pred of the observation group was much lower than that of in the control group (t=18.673, P<0.05). To further analyze the data of children with asthma, a positive correlation between FeNO and sputum EOS was observed (r=0.265, P=0.005), but there was no correlation between FEV1%pred and sputum EOS (r=0.158, P=0.093). Conclusions In children with asthma, there is a positive correlation between FeNO and sputum EOS, but no correlation between FEV1%pred and sputum EOS. Key words: Asthma; Child; Induced sputum eosinophils; Lung function; Fractional exhaled nitric oxide concentration