Phenotyping patients with chronic cough: Evaluating the ability to predict the response to anti-inflammatory therapy

Whether the fraction of exhaled nitric oxide (FeNO) measurement can predict the response to anti-inflammatory treatment in chronic cough is unknown.

To explore whether the effectiveness of treatment with 10 mg of montelukast or 20 mg of prednisolone in patients with chronic cough is predicted by FeNO level.

In this randomized, open-label, controlled pilot study conducted in the Clinical Trial Unit in Castle Hospital in the United Kingdom, 50 nonsmoking patients with a cough that lasted more than 8 weeks were sequentially enrolled in the study. Thirty patients with high FeNO levels (≥30 ppb) were randomized in a 1:1 ratio to receive 10 mg of montelukast or 20 mg of prednisolone for 2 weeks followed by 10 mg of montelukast for 2 weeks. Twenty patients with a low FeNO level (≤20 ppb) received 10 mg of montelukast. The primary objective was to determine the effectiveness of treatment on 24-hour cough counts.

The 24-hour cough counts decreased in both groups by approximately 50% (P < .005), indicating that FeNO did not predict treatment response. However, it was a good marker for eosinophilic inflammation with a high degree of correlation with blood and sputum eosinophilia (P < .001).

These results suggest that prior investigation may not predict response to anti-inflammatory treatment, which may be consequent on localized leukotriene-mediated inflammation.

ClinicalTrials.gov Identifier: NCT02479074.