Could Fractional Exhaled Nitric Oxide Test be Useful in Predicting Inhaled Corticosteroid Responsiveness in Chronic Cough? A Systematic Review

Abstract

We did not find strong evidence to support the use of Feno tests for predicting ICS responsiveness in chronic cough. Further studies need to have a randomized, placebo-controlled design, and should use validated measurement tools for cough. Standardization would facilitate the development of clinical evidence.

Diagnostic accuracy of fractional exhaled nitric oxide measurement in predicting cough-variant asthma and eosinophilic bronchitis in adults with chronic cough: A systematic review and meta-analysis

“…To the best of our knowledge, no studies have used validated cough measurement tools to examine such utility in nonasthmatic patients with chronic cough. 17 Several major limitations need to be considered in interpreting our findings. First, heterogeneity could not be fully investigated because of the limited number of studies included.…”

“…We used this search strategy because we previously found that the number of publications was not excessive. 17 Additional searches were performed by using Google Scholar and all cross-referenced articles. Eligibility criteria are provided in the Methods section in this article's Online Repository at www.jacionline.org.…”

KAAACI Evidence-Based Clinical Practice Guidelines for Chronic Cough in Adults and Children in Korea

“…However, it should be noted that the utility of FeNO is just to characterize the nature of airway inflammation (and thus can predict the anti-inflammatory treatment responses), but is not to confirm the diagnosis of asthma. 51 Asthma is increasingly recognized as a heterogenous condition 52 and is not definable by the presence of type 2 inflammation alone. Elevated FeNO levels in chronic cough patients with normal chest X-rays may suggest not only cough variant asthma but also eosinophilic bronchitis.…”

The Emerging Role of The Eosinophil and Its Measurement in Chronic Cough

“…It has been reported that the level of FeNO in patients using corticosteroids decreases quickly while airway inflammation and hyperresponsiveness can still be detected by other markers of airway inflammation [67]. Therefore, the reliability of FeNO as a guide to therapy could be questioned and FeNO might be too sensitive to the initiation of corticosteroid therapy.…”