Chronic cough and sputum production are associated with worse clinical outcomes in stable asthma.
BACKGROUND
Chronic cough and sputum production (chronic mucus hypersecretion) is a poorly described clinical feature of asthma. Our objective was to identify clinical, immunological and computed tomography (CT) measures of airway wall dimensions associated with these symptoms in smokers and never smokers with asthma.


METHODS
Cross-sectional data was analysed from 120 smokers and never smokers with asthma. Participants with and without a history of chronic mucus hypersecretion were compared for clinical outcomes, sputum differential cell counts and CT measures of airway dimensions (wall thickness, luminal area and percent wall area).


RESULTS
Chronic mucus hypersecretion occurred in a higher proportion of smokers with asthma (56%) than never smokers with asthma (20%), (p < 0.001) and the proportion of patients with these symptoms increased with asthma severity (p = 0.003). Smokers with asthma and chronic mucus hypersecretion had worse current clinical control than smokers without those symptoms [ACQ score 2.3 versus 1.6, p = 0.002]. A greater proportion of never smokers with chronic mucus hypersecretion required short courses of oral corticosteroids in the last year (58% versus 19%, p = 0.011). Sputum neutrophil and eosinophil counts were similar in asthma patients with or without chronic mucus hypersecretion. Of those with severe asthma and chronic mucus hypersecretion, a CT measure of airway lumen area was reduced in smokers compared to never smokers (11.4 mm(2) versus 18.4 mm(2); p = 0.017).


CONCLUSIONS
Chronic mucus hypersecretion occurs frequently in adults with stable asthma, particularly in smokers with severe disease and is associated with worse current clinical control in smokers and more exacerbations in never smokers.
Institute of Infection, Immunity & Inflammation, University of Glasgow, Glasgow, UK. Electronic address: neil.thomson@glasgow.ac.uk.
Neil C
NC
Thomson
Rekha
R
Chaudhuri
C Martina
CM
Messow
Mark
M
Spears
William
W
MacNee
Martin
M
Connell
John T
JT
Murchison
Michael
M
Sproule
Charles
C
McSharry
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D002908:Chronic Disease; D003371:Cough / Q000209:etiology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007958:Leukocyte Count; D008875:Middle Aged; D009093:Mucus / Q000378:metabolism; D011379:Prognosis; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects / Q000503:physiopathology; D013183:Sputum / Q000166:cytology / Q000378:metabolism*; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity / Q000502:physiology; D055815:Young Adult
Asthma; Asthma control; Cough; Exacerbations; Smokers; Sputum