Mucus hypersecretion in asthma is associated with rhinosinusitis, polyps and exacerbations.

Background: Bronchial hypersecretion is a poorly studied symptom in asthma. The aim of the study was to determine the specific characteristics of asthmatics with bronchial hypersecretion.

Methods: A total of 142 asthmatics (21.8% men; mean age 49.8 years) were prospectively followed for one year. Mucus hypersecretion was clinically classified into two severity categories: daily sputum production and frequent expectoration but not every day. Clinical and pulmonary function variables associated with mucus hypersecretion were assessed by multiple logistic regression analysis.

Results: Daily cough was recorded in 28.9% of patients and sputum production daily or most of the days in 52.1%. Patients with mucus hypersecretion had more dyspnoea, poorer asthma control and quality of life, had suffered from more exacerbations and showed anosmia associated with chronic rhinosinusitis and nasal polyposis more frequently. Factors associated to mucus hypersecretion were anosmia, one exacerbation or more in the previous year and FEV1/FVC <70% (AUC 0.75, 95% CI 0.66-0.85) for the first definition of hypersecretion, and anosmia, poor asthma control and age (AUC 0.75, 95% CI 0.67-0.83) for the second definition.

Conclusions: Mucus hypersecretion is frequent in patients with asthma, and is associated with chronic upper airways disease, airway obstruction, poor asthma control and more exacerbations.