What is a clinically meaningful change in exhaled nitric oxide for children with asthma?

Fractional exhaled nitric oxide (FE NO) may be a useful objective measurement to guide asthma treatment. What remains uncertain is what change in FE NO is clinically significant.An individual patient data analysis was performed using data from seven randomized clinical trials which used FE NO to guide asthma treatment. The absolute and percentage intra-subject change in FE NO measurements over "stable" and also "unstable" 3-month periods were...