FENO Guided Therapy in Asthma: A Non-inferiority Study

Abstract

Introduction: Measurement of fractional nitric oxide concentration in exhaled breath (FeNO) is a safe method of measuring airway inflammation. However, its position in the management of asthma is poorly defined. Aims and Objectives: To assess the non-inferiority of FeNO guided therapy as compared to Asthma Control Test (ACT) guided therapy in terms of the mean dose of inhaled corticosteroids(ICS) & increment in ACT score in patients with mild intermittent asthma. Materials and Methods: Patients (n=80) fulfilling inclusion criteria were randomized alternately to a FeNO guided (study) group and an ACT guided (control) group and was started on an ICS (400mcg) along with a LABA. In both groups, ICS dose was titrated (in terms of step up and step down) based on the FeNO level and ACT score over a period of 6 months. Data was collected and submitted for multivariate analysis. Results: Although the mean dose of ICS was higher in the control group than in the study group, the difference was not statistically significant(p-value=0.63). The increment in ACT score was greater in the study group than in the control group (2.45 vs 1.88), but this difference also was not statistically significant (p-value=0.5). Similarly, Frequency of step up and Step down in both groups was not statistically significant either (p-value=0.74). There was a significant inverse co-relation seen between FeNO levels and ACT score (r= -0.274, p-value- 0.043) Conclusion: This study shows that FENO remains an expensive option as compared to clinical monitoring (ACT score) in step up and step down treatment of asthma. The results of our study may give confidence for further utilization of ACT score as a treatment guide in asthma patients, especially in conditions where FeNO is not available.