Role and Impact of Chronic Cough in Individuals with Asthma From the General Population.

BACKGROUND

Cough is a well-recognized symptom in asthma, but the role and impact of chronic cough in individuals with asthma has not been described in the general population.

OBJECTIVE

We hypothesized that among individuals with asthma, those with chronic cough versus those without have a more severe disease phenotype.

METHODS

We identified individuals with asthma and chronic cough among 14,740 adults from the Copenhagen General Population Study, and investigated respiratory symptoms, health care utilizations, lung function, and biomarkers in blood.

RESULTS

A total of 855 (6%) individuals suffered from asthma, and 70 (8%) had chronic cough. Individuals with asthma and chronic cough had a Leicester Cough Questionnaire median total score of 16.8 (25th and 75th percentiles, 14.8-18.9), corresponding to 5.4 (4.6-6.0) for the physical domain, 5.7 (4.6-6.4) for the psychological domain, and 6.0 (5.3-6.8) for the social domain. Among individuals with asthma, those with chronic cough versus those without reported more often wheezing (70% vs 54%), dyspnea (74% vs 49%), night-time dyspnea (27% vs 11%), sputum production (59% vs 14%), chest pain/tightness (14% vs 4%), acute bronchitis/pneumonia episodes, and general practitioner visits. Furthermore, these individuals had more often FEV1 predicted value of less than 60% (14% vs 7%) and higher levels of neutrophils, leukocytes, and fibrinogen in blood, but there were no differences with regard to levels of high-sensitive C-reactive protein, eosinophils, and IgE in blood.

CONCLUSIONS

Chronic cough in individuals with asthma is associated with a more severe disease phenotype in terms of worse respiratory symptoms, greater health care utilizations, lower lung function, and higher levels of systemic inflammatory biomarkers in blood.