Martins C, et al. - Given to the investigation, spirometry and exhaled nitric oxide were two important complimentary tools to identify and assess asthma control in children. This study was executed to ascertain the ability of a new suggested spirometry adjusted exhaled nitric oxide (NO) index in doing that. According to findings, exhaled NO did not allow to identify childhood asthma. Results demonstrated the better performance of spirometry adjusted fraction of exhaled NO assessing asthma control in children. These results suggested its use in epidemiological studies to assess asthma control. However, more validation studies were needed.

Methods

• A health questionnaire, skin-prick tests, spirometry with bronchodilation and exhaled NO screened a random sample of 1602 schoolchildren.
• A total of 662 children were included with median (IQR) exhaled NO 11(14) ppb.
• In order to identify asthmatic children and uncontrolled asthma, ROC curves using exhaled NO equations from Malmberg, Kovesi and Buchvald, and spirometry adjusted exhaled NO values were applied.

Results

• This study highlighted the incapability of ROC curves to identify asthmatic children (all AUC<0.700).
• Data demonstrated a fair and increased ability of spirometry adjusted exhaled NO/FEV1 (AUC=0.712; p=0.010) and NO/FEF25-75% (AUC=0.735 p=0.004) to identify uncontrolled disease compared with exhaled NO (AUC=0.707; p=0.011) or the Malmberg equation (AUC=0.701; p=0.014).
• In addition, sensitivity and specificity identifying non-controlled asthma was of 59% and 81%, respectively, for the cut-off value of 9.7 ppb/L for exhaled NO/FEV1, and 40% and 100% for 15.7 ppb/L/s for exhaled NO/FEF25-75%.