297 Relationship Between Exhaled Nitric Oxide and Levels of Asthma Control in Asthma Patients Treated with Inhaled Corticosteroid

Abstract

Background

While asthma control is defined as the extent to which the various manifestations of asthma are reduced by treatment, current guidelines of asthma recommend assessment of asthma control without consideration of airway inflammation. Our aim was to investigate the relationships between fractional exhaled nitric oxide (FeNO), a reliable marker of airway inflammation, and levels of asthma controls in patients treated with inhaled corticosteroid (ICS).

Methods

We enrolled 71 adult patients with asthma, who had been treated with ICS more than 4 months. Asthma control was assessed by the physician based on the Global Initiative for Asthma guidelines, and by the patients and by using Asthma Control Test (ACT). Statistical analyses were performed to analyze the relationships between FeNO and measures of asthma control and clinical indices for asthma manifestations.

Results

There was no significant difference in FeNO levels between 3 groups according to levels of asthma control (controlled, partly controlled and uncontrolled) determined by the physician ( P = 0.81) and by the patients ( P = 0.81). In addition, FeNO values were not correlated with the ACT scores ( r = 0.031, P = 0.807), while FeNO showed peripheral blood eosinophil counts ( P < 0.001).

Conclusions

These findings demonstrated that FeNO levels are not related with the measures of asthma control in patients treated with ICS. Information of airway inflammation from FeNO concentrations seems to be discrepant from levels of asthma control.