Functional gastrointestinal disorders are associated with capsaicin cough sensitivity in severe asthma.

Abstract

BACKGROUND:

Although sensory nerve dysfunction is related to the pathology of severe uncontrolled asthma and functional gastrointestinal disorders (FGIDs), the impact of comorbid FGIDs on the pathophysiology of severe uncontrolled asthma remains poorly understood. The aim was to clarify the physiological relationships between severe uncontrolled asthma and FGIDs.

METHODS:

Fifty-two patients with severe uncontrolled asthma who visited our hospital between September 2016 and August 2019 were retrospectively analyzed. Clinical characteristics, other comorbidities including gastroesophageal reflux disease (GERD), and biomarkers such as fractional nitric oxide (FeNO) and capsaicin cough sensitivity (C-CS) before the beginning of biologics or bronchial thermoplasty, were compared between patients with and without comorbid FGIDs. C-CS was evaluated by C5 (concentration of inhaled capsaicin that induced five or more coughs), and C5 ≤2.44 μM was defined as heightened C-CS.

RESULTS:

Seventeen patients had comorbid FGIDs. These patients had a lower FeNO level (21.9 ± 1.7 ppb vs. 33.9 ± 2.8 ppb, P = 0.04), a lower C5 threshold (2.24 ± 2.88 μM vs. 8.91 ± 5.5 μM, P < 0.001), a higher prevalence of comorbid GERD (64.7% vs. 31.7%, P = 0.03), and a higher prevalence of heightened C-CS (70.6% vs. 28.6%, P = 0.007) than those without FGIDs. Analysis of covariance showed a significant effect of FGIDs on C-CS in severe uncontrolled asthma without being affected by GERD.

CONCLUSIONS:

Comorbid FGIDs are associated with heightened C-CS in patients with severe uncontrolled asthma, and they may be an important extra-respiratory manifestation of the airway neuronal dysfunction phenotype of severe uncontrolled asthma.

• Authors: Keima Ito, Yoshihiro Kanemitsu, Takeshi Kamiya, Kensuke Fukumitsu, Norihisa Takeda, Tomoko Tajiri, Ryota Kurokawa, Hirono Nishiyama, Jennifer Yap, Satoshi Fukuda, Takehiro Uemura, Hirotsugu Ohkubo, Ken Maeno, Yutaka Ito, Tetsuya Oguri, Masaya Takemura, Akio Niimi
• Journal: Allergology international : official journal of the Japanese Society of Allergology (Allergol Int) Vol. 72 Issue 2 Pg. 271-278 (Apr 2023) ISSN: 1440-1592 [Electronic] England
• PMID: 36192325 (Publication Type: Journal Article)
• Copyright: Copyright © 2022 Japanese Society of Allergology. Published by Elsevier B.V. All rights reserved.

Chemical References

• Capsaicin

Topics

• Humans
• Cough
• Capsaicin
• Retrospective Studies
• Asthma
• Gastroesophageal Reflux (epidemiology, complications)