Abstract
Background: Fractional Exhaled Nitric Oxide (FeNO) is a promising non invasive tool for detecting airway inflammation; however, it's utility in predicting asthma control is not well defined.
Aims and Objectives: The ability of serial measurements of FeNO in determining and predicting clinical control of asthma was investigated.
Methods: Steroid naïve asthmatics who were clinically eligible for receiving ICS were recruited and the following parameters were measured at inclusion and after 6 - 8 weeks of ICS treatment: FeNO (using Niox Mino point of care device), peak expiratory flow rate (PEFR) variability, asthma control test (ACT) score, forced expiratory volume in 1 sec (FEV1), and bronchodilator reversibility (BDR).
Results: 96 patients were recruited (61% males; mean (SD) age, 33.4 (12.8) years). The median FeNO levels at baseline and after therapy were 41.5 (25 - 66) and 35.5 (19 - 47) ppb respectively (p=0.01).
At baseline, FeNO levels correlated strongly with FEV1 (R= - 0.62, p< 0.001), ACT score (R= - 0.75, p< 0.001) and PEFR variability (R= - 0.77, p< 0.001) and moderately with BDR (R= 0.49, p< 0.001). Following ICS therapy, correlations remained strong with ACT score (R= -0.65, p< 0.001) and PEFR variability (R= -0.58, p=0.005) but not with FEV1(R= - 0.24, p=0.06) and BDR (R= 0.22, p=0.08).
Conclusions: FeNo levels correlate well with conventional parameters of clinical control in moderate bronchial asthma and may be a simple, non-invasive and useful method for assessing level of asthma control.
- Copyright ©the authors 2016