Chronic cough in adults is defined in clinical guidelines as a cough lasting ≥8 weeks and is a common reason for seeking medical care worldwide as it has a significant impact on daily life and quality of life. A systematic review and meta-analysis including more than 90 studies reported a global prevalence of chronic cough of 9.6%, with a higher rate in Europe (12.7%).
The concept of cough hypersensitivity has been increasingly suggested as the mechanism underlying many of the multifactorial causes of chronic cough; in fact, the European Respiratory Society (ERS) guidelines proposed cough hypersensitivity syndrome as a general diagnosis.
Within this general term, new phenotypes and different groups, specifically, are considered.
Chronic cough is defined as a constant cough lasting 8 weeks or longer, and the concept of cough sensitivity has been suggested as an underlying mechanism of the condition.
Its prevalence has been estimated at 9.6% worldwide and 12.7% in Europe alone. The European Respiratory Society (ERS) guidelines suggest cough hypersensitivity syndrome as the general diagnosis, with phenotypes including:
- Asthmatic cough/eosinophilic bronchitis
- Gastroesophageal reflux disease (GERD) with cough
- Postnasal drip syndrome/upper respiratory cough syndrome (UACS)
- Cough due to angiotensin-converting enzyme inhibitors (ACE inhibitor). Chronic refractory cough (or unexplained/idiopathic chronic cough)
- Chronic cough in other diseases
- Chronic cough related to tobacco and nicotine
However, the prevalence and characteristics of these phenotypes in the general population are unknown.
Fundamental reason
Recent guidelines consider chronic cough as a single clinical entity with different phenotypes. Our objective was to investigate them in a general population and describe the prevalence, distribution and characteristics of these phenotypes within the Austrian general population.
Methods
From the LEAD study, a population-based longitudinal observational cohort, questionnaire and spirometry data from 10,057 adult participants were analyzed. Chronic cough was defined as coughing almost every day during the past 12 months for at least 3 months (>12 weeks).
Results
The prevalence of chronic cough was 9% and increased with age.
We did not find a predominance of sex but we did find a predominance of female sex (68%) in never smokers.
Presumptive cause was identified in 85% of which more than half (53.9%) had two phenotypes, 36.9% belonged to only one and 9.2% to three or more.
Regarding the distribution of phenotypes, 40.8% were active smokers, 32.6% took ACE inhibitors, 18.2% GERD, 17.6% asthmatic cough, 9.7% UACS and 28.3% other diseases associated with chronic cough.
15% had unexplained chronic cough with no identifiable phenotype.
Current smoking, low socioeconomic status, obesity, COPD, and obstructive sleep apnea were factors associated with chronic cough.
Conclusion
Chronic cough is common among adults in Austria and very common in the older population. Most participants can be phenotyped with a simple questionnaire-based assessment and can therefore potentially receive specific treatment without an intensive clinical study.
