Effect of Chewing Gum on Fractional Exhaled Nitric Oxide Values in Patients with Asthma: A Proof of Concept Study

Maria Aetou , Ingmar Bergs , Sitraka Faniry Nantenaina Ratsimba, Jens Spiesshoefer, Michael DreherDepartment of Pneumology and Intensive Care Medicine, University Hospital RWTH Aachen, Aachen, GermanyCorrespondence: Maria Aetou, Department of Pneumology and Intensive Care Medicine, University Hospital RWTH Aachen, Pauwelsstrasse 30, Aachen, 52074, Germany, Tel +49 2418088763, Email maetou@ukaachen.dePurpose: Fractional exhaled nitric oxide (FeNO) is an important biomarker that is used to phenotype patients with (severe) asthma. This study evaluated the effect of chewing gum on FeNO values.Patients and Methods: Patients with stable asthma and elevated FeNO (≥ 25 ppb) were randomised to the control group (no chewing gum) or to chew gum for 15 minutes after a baseline FeNO measurement. A second FeNO measurement was performed 15 minutes after the first. The primary endpoint was the change in FeNO from baseline to 15 minutes.Results: Thirty patients with asthma (15 male, age 52± 15 years) were randomised to the control or chewing gum group. Clinical characteristics, medications, laboratory testing and pulmonary function did not differ significantly between the two groups. The change in FeNO from baseline to 15 minutes was – 3.3 ppb in the chewing gum group (p=0.02 vs. baseline) and +3.2 ppb in the control group (p=0.003 vs. baseline); the between-group difference for this change (median – 13% in the chewing gum group vs. median +7% in the control group) was statistically significant (p=0.001).Conclusion: The present study showed for the first time that chewing gum influences FeNO measurement in patients with asthma. This is clinically relevant because FeNO is an important biomarker for the diagnosis, phenotyping and antibody-based treatment of asthma. Based on our findings, patients should be advised not to chew gum before the measurement of FeNO.Keywords: asthma, fractional exhaled nitric oxide, chewing, gum