The Objective Assessment of Cough Frequency in Bronchiectasis

Introduction Cough in bronchiectasis is associated with
significant impairment in health status. This study aimed to
quantify cough frequency objectively with a cough monitor
and investigate its relationship with health status. A secondary
aim was to identify clinical predictors of cough
frequency.
Methods Fifty-four patients with bronchiectasis were
compared with thirty-five healthy controls. Objective 24-h
cough, health status (cough-specific: Leicester Cough
Questionnaire LCQ and bronchiectasis specific:
Bronchiectasis Health Questionnaire BHQ), cough severity
and lung function were measured. The clinical predictors of
cough frequency in bronchiectasis were determined in a
multivariate analysis.
Results Objective cough frequency was significantly raised
in patients with bronchiectasis compared to healthy controls
[geometric mean (standard deviation)] 184.5 (4.0) vs.
20.6 (3.2) coughs/24-h; mean fold-difference (95% confidence
interval) 8.9 (5.2, 15.2); p\0.001 and they had
impaired health status. There was a significant correlation
between objective cough frequency and subjective measures;
LCQ r = -0.52 and BHQ r = -0.62, both
p\0.001. Sputum production, exacerbations (between
past 2 weeks to 12 months) and age were significantly
associated with objective cough frequency in multivariate
analysis, explaining 52% of the variance (p\0.001).
There was no statistically significant association between
cough frequency and lung function.
Conclusions Cough is a common and significant symptom
in patients with bronchiectasis. Sputum production, exacerbations
and age, but not lung function, were independent
predictors of cough frequency. Ambulatory objective
cough monitoring provides novel insights and should be
further investigated as an outcome measure in
bronchiectasis.