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PLoS One. 2014 Nov 19;9(11):e113057. doi: 10.1371/journal.pone.0113057. eCollection 2014.

Capsaicin cough sensitivity and the association with clinical parameters in bronchiectasis.

Author information

1
State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.
2
Department of Respiratory and Critical Care Medicine, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
3
Guangzhou First People's Hospital, Guangzhou, Guangdong, China.

Abstract

BACKGROUND:

Cough hypersensitivity has been common among respiratory diseases.

OBJECTIVE:

To determine associations of capsaicin cough sensitivity and clinical parameters in adults with clinically stable bronchiectasis.

METHODS:

We recruited 135 consecutive adult bronchiectasis patients and 22 healthy subjects. History inquiry, sputum culture, spirometry, chest high-resolution computed tomography (HRCT), Leicester Cough Questionnaire scoring, Bronchiectasis Severity Index (BSI) assessment and capsaicin inhalation challenge were performed. Cough sensitivity was measured as the capsaicin concentration eliciting at least 2 (C2) and 5 coughs (C5).

RESULTS:

Despite significant overlap between healthy subjects and bronchiectasis patients, both C2 and C5 were significantly lower in the latter group (all P<0.01). Lower levels of C5 were associated with a longer duration of bronchiectasis symptoms, worse HRCT score, higher 24-hour sputum volume, BSI and sputum purulence score, and sputum culture positive for P. aeruginosa. Determinants associated with increased capsaicin cough sensitivity, defined as C5 being 62.5 µmol/L or less, encompassed female gender (OR: 3.25, 95%CI: 1.35-7.83, P<0.01), HRCT total score between 7-12 (OR: 2.57, 95%CI: 1.07-6.173, P = 0.04), BSI between 5-8 (OR: 4.05, 95%CI: 1.48-11.06, P<0.01) and 9 or greater (OR: 4.38, 95%CI: 1.48-12.93, P<0.01).

CONCLUSION:

Capsaicin cough sensitivity is heightened in a subgroup of bronchiectasis patients and associated with the disease severity. Gender and disease severity, but not sputum purulence, are independent determinants of heightened capsaicin cough sensitivity. Current testing for cough sensitivity diagnosis may be limited because of overlap with healthy subjects but might provide an objective index for assessment of cough in future clinical trials.

PMID:
25409316
PMCID:
PMC4237391
DOI:
10.1371/journal.pone.0113057
[Indexed for MEDLINE]
Free PMC Article

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