Bronchiectasis is the main risk factor for chronic cough patients at the individual level, new Danish research shows.
Dr. Morten Dahl of Denmark’s Zealand University Hospital in Køge led the study, “Risk Factors for Chronic Cough Among 14,669 Individuals From the General Population,” which appeared in Chest Journal.
Many patients with cough who need medical assistance suffer from chronic cough, defined as lasting more than eight weeks. Yet despite its prevalence, little is known about the risk factors for chronic cough at the individual and community levels.
Dahl’s team determined and ranked risk factors for chronic cough using data from 14,669 individuals. They collected patient data from the Copenhagen General Population Study, a cohort study that began in 2003 and which is still enrolling participants. Researchers assessed severity of chronic cough using a questionnaire that analyzed physical, psychological and social issues.
Scientists found that 4 percent of the general population had chronic cough, including 3 percent among those who had never smoked and 8 percent in current smokers. The analysis revealed that individuals were affected more psychologically than socially. Women also scored lower in the physical domain, though researchers observed no other statistical differences between men and women.
At the individual level, the top three risk factors among never-smokers were bronchiectasis, asthma and gastroesophageal reflux disease (GERD, which causes heartburn or acid indigestion. Among former smokers, the top three were bronchiectasis, asthma and occupational exposure to dust or fumes. Among current smokers, the top risk factor was airflow limitation.
At the community level, the top three risk factors among never-smokers were being female, asthma and GERD. Among former smokers, they were abdominal obesity, low income and asthma. As with the individual level, the top risk among current smokers was airflow limitation.
The results highlight the importance of bronchiectasis as a risk factor for chronic cough.
“Because the treatment of bronchiectasis may be difficult, interdisciplinary specialized initiatives are necessary,” authors wrote, adding that chronic cough in asthma patients may be a sign of undertreatment, with probable benefits arising from treatment with inhaled corticosteroids.
Smoking’s relevance for chronic cough at the community level was not surprising. It is well-established that smoking causes coughing and other respiratory symptoms. The lack of difference in never-smokers and former smokers in terms of smoking’s importance in chronic cough indicates that smoking’s effects are mostly reversible. Therefore, “smoking cessation is mandatory in the management of patients with chronic cough,” authors advise.
Importantly, bronchiectasis is not included in the group of causes that physicians are urged to evaluate in chronic cough patients. The discrepancy highlights the difficulty of extrapolating guidelines to general practice, the authors wrote, concluding that “strategies to prevent and treat modifiable chronic cough risk factors should be tailored accordingly.”