Most Common Chronic Respiratory Illnesses and Their Management
The Two Dominant Chronic Respiratory Diseases
Chronic Obstructive Pulmonary Disease (COPD) and asthma are the two most common chronic respiratory illnesses, together ranking as the third leading cause of death in the European Union and fourth in North America. 1
Chronic Obstructive Pulmonary Disease (COPD)
Definition and Core Characteristics
COPD is a common, preventable, and treatable disease characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities, usually caused by significant exposure to noxious particles or gases. 1
- The airflow limitation is largely irreversible and progressive, not changing markedly over several months 2, 3
- Diagnosis requires spirometry showing post-bronchodilator FEV1/FVC ratio <0.70 1
- COPD affects approximately 16 million Americans, occurring in 10-15% of smokers 4
Clinical Presentation
The cardinal symptoms include: 1
- Dyspnea (chronic and progressive, the most characteristic symptom and major cause of disability)
- Chronic cough (often the first symptom, frequently discounted by patients)
- Sputum production (regular production for ≥3 months in 2 consecutive years defines chronic bronchitis)
- Wheezing and chest tightness (variable throughout the day)
- In severe disease: fatigue, weight loss, and anorexia 1
Risk Factors and Pathophysiology
- Tobacco smoking is the main risk exposure, but environmental factors like biomass fuel exposure and air pollution contribute significantly 1
- Occupational exposures are important risk factors after smoking 3
- Host factors including genetic abnormalities, abnormal lung development, and accelerated aging predispose individuals 1
- The disease results from chronic inflammation that differs from asthma, affecting predominantly small airways with emphysema and decreased diffusing capacity 2
Disease Progression and Prognosis
- FEV1 declines approximately 70 ml per year 2
- 10-year survival is approximately 30% in community surveys 2
- The disease is punctuated by acute exacerbations (acute worsening of respiratory symptoms) 1, 3
GOLD Classification System
The current GOLD 2017 classification separates spirometric assessment from symptom evaluation for treatment decisions: 5
Spirometric Grades (based on FEV1% predicted): 5
- GOLD 1 (Mild): FEV1 ≥80%
- GOLD 2 (Moderate): FEV1 50-79%
- GOLD 3 (Severe): FEV1 30-49%
- GOLD 4 (Very Severe): FEV1 <30%
ABCD Assessment Groups (derived exclusively from symptoms and exacerbation history): 5
- Group A: Low symptoms + Low exacerbation risk
- Group B: High symptoms + Low exacerbation risk
- Group C: Low symptoms + High exacerbation risk
- Group D: High symptoms + High exacerbation risk
Management Approach
First-line pharmacologic therapy consists of long-acting bronchodilators (LAMAs or LABAs), not inhaled corticosteroids. 2
- For Groups A-D, escalation strategies for pharmacologic treatments are proposed based on symptom burden and exacerbation history 1
- The concept of deescalation of therapy is now incorporated into treatment assessment 1
- Combination therapy with tiotropium (LAMA) and olodaterol (LABA) is available for maintenance treatment 6
Non-pharmacologic interventions are critical: 1
- Smoking cessation remains the priority for prevention and slowing disease progression 1
- Exercise rehabilitation improves exercise capacity, physical fitness, and pulmonary function by enhancing immune response, controlling inflammation, and improving gas exchange 7
- Pulmonary rehabilitation reduces adverse symptoms by relieving respiratory limitations and enhancing skeletal muscle function 7
Comorbidities
Concomitant chronic diseases occur frequently in COPD patients and independently affect mortality and hospitalizations, requiring treatment. 1, 3
Common comorbidities include: 8
- Atherosclerosis and cardiac failure
- Diabetes
- Osteoporosis
- Cachexia
- Gastroesophageal reflux disease
- Depression
Asthma
Key Distinguishing Features from COPD
Asthma demonstrates variable and often reversible airflow limitation that responds significantly to bronchodilators or corticosteroids, in contrast to COPD's largely irreversible obstruction. 2
- Asthma is characterized by eosinophilic inflammation in adults 2
- Airflow limitation is often reversible either spontaneously or with therapy, with marked improvement on spirometry with bronchodilators or glucocorticosteroids 2
Clinical Overlap
Approximately 20% of patients with obstructive airways diseases have features of both COPD and asthma, with the highest risk of mortality (HR 1.45). 2
- Differentiation of severe COPD from chronic severe asthma is difficult since some degree of FEV1 reversibility can often be produced by bronchodilator therapy in both conditions 2
- Asthma may be a risk factor for the development of chronic airflow limitation and COPD 1
Management Approach
First-line therapy for asthma consists of inhaled corticosteroids (ICS) as controller medication, with short-acting beta-agonists as needed for symptom relief. 2
This represents a fundamental difference from COPD management, where long-acting bronchodilators are first-line rather than inhaled corticosteroids 2
Other Chronic Respiratory Diseases
While COPD and asthma dominate, other chronic respiratory conditions include: 7, 4
- Bronchiectasis (may present with large volumes of sputum production) 1
- Interstitial lung disease (some forms associated with airflow obstruction) 7, 4
- Bronchiolar diseases 4
- Upper airway lesions 4
These less common forms are often misdiagnosed due to poor recognition and uncommon occurrence 4
Critical Diagnostic Approach
Spirometry is required to establish the diagnosis of COPD and should be performed in any patient with dyspnea, chronic cough, sputum production, and/or history of exposure to risk factors. 1
- Good-quality spirometry should be accessible in any healthcare setting 1
- Physical examination alone is rarely diagnostic, as physical signs are usually not identifiable until significantly impaired lung function is present 1
- There is no single diagnostic test for COPD; diagnosis relies on clinical judgment based on history, physical examination, and confirmation of airflow obstruction using spirometry 3
Public Health Impact
Deaths due to COPD have been second only to coronary heart disease since 2014, causing approximately 64 deaths per 100,000 population. 9