Study population
Between January 2012 and January 2014, the patients with asthma, aged
6-18 years old, were invited to the study while their routine asthma
follow-up at the outpatient clinic of Pediatric Allergy Department of a
tertiary research and training hospital. The must inclusion criteria was
to have physician diagnosed asthma based on criteria recommended by the
GINAand the US National Asthma Education and Prevention
Program.1, 3 The others were to be adherent to their
asthma treatment, able to perform FeNO and spirometry measurements
properly according to the guidelines. Children were excluded if they did
not meet all inclusion criteria or had comorbid diseases other than
allergic diseases, if they were having an acute attack or respiratory
infection which were unfavorable for FeNO and spirometry tests. The
study was approved by the Institutional Review Board. Parent/caregiver
provided informed consent and writtten assent was taken from children
older than 6 years old.