Yes, Cough is a Cardinal Symptom of COPD
Cough is definitively one of the most frequent and characteristic symptoms of chronic obstructive pulmonary disease (COPD), along with dyspnea and sputum production. 1
Primary Symptom Profile
Dyspnea, cough, and/or sputum production are the most frequent symptoms in COPD patients, though these symptoms are commonly underreported. 1 The cough in COPD is typically:
- Chronic and productive, often worse in the morning 2
- Present in most patients and sometimes dominates the clinical picture 2
- Persistent, occurring on most days for at least 3 months of the year for at least 2 consecutive years when meeting criteria for chronic bronchitis 1
Clinical Significance of Cough in COPD
The presence of chronic cough carries important prognostic implications:
- Patients with chronic cough exhibit lower FEV1 (% predicted), lower diffusing capacity, more frequent acute exacerbations, more severe dyspnea, and worse quality of life compared to COPD patients without chronic cough 3
- Chronic cough is an independent risk factor for lower lung function, more severe dyspnea, and poor quality of life 3
- The risk of future acute exacerbations is significantly associated with chronic cough (odds ratio 1.56,95% CI 1.08-2.24), but interestingly not with chronic sputum alone 3
Relationship to Chronic Bronchitis Component
Approximately 14 million of the 16 million Americans with COPD have the chronic bronchitis phenotype, which is specifically defined by chronic cough and sputum production. 4 The American Thoracic Society defines chronic bronchitis as cough and sputum expectoration occurring on most days for at least 3 months per year for at least 2 consecutive years when other causes are excluded. 1, 5
Clinical Patterns and Severity
Pulmonary function, dyspnea severity, and quality of life worsen in the following order: patients without cough or sputum → patients with sputum only → patients with cough only → patients with both (chronic bronchitis). 3 This hierarchical pattern demonstrates that cough represents a more severe phenotype than sputum production alone.
Common Pitfalls
- Symptoms are commonly underreported by patients 1, so direct questioning about cough frequency, timing, and productivity is essential
- The overdiagnosis of chronic bronchitis by patients and physicians may be very common 1, as the term "bronchitis" is often used as a nonspecific descriptor for self-limited cough
- The absence of cough does not exclude COPD 2, as some patients may present primarily with dyspnea