Airway calibre variation is a major determinant of exhaled nitric oxide's ability to capture asthma control

Changes in airway calibre have the potential to modify exhaled nitric oxide fraction ( ) values and could hamper how captures changes in asthma control. Here, our objective was to assess whether forced expiratory volume in 1 s (FEV ) variations alter the ability of to reflect asthma control. , asthma control (Asthma Control Questionnaire (ACQ)) and FEV were measured at least two times in 527 patients during 1819 pairs of visits. Determinants of -ACQ discordance probability were evaluated through a logistic regression analysis. The effectiveness of at capturing either asthma control worsening or improvement between two visits was then assessed by undertaking a stratified receiver operating characteristic curves analysis.When FEV and change in the same direction, the odds of -ACQ being discordant are multiplied by 3 (p