Pulmonary

Diagnosis and Management of Stable COPD

SUMMARY:

Chronic obstructive pulmonary disease (COPD), a progressive respiratory condition characterized by dyspnea due to airflow limitation, is the fourth leading cause of death worldwide, and its prevalence is expected to increase in the coming decades. Though it is strongly associated with smoking, other causes include air pollution, indoor biomass fuel exposure, and occupational exposure to hazardous gases and dusts. There are also genetic and developmental factors that may predispose a person to developing COPD. The underlying pathophysiology of COPD involves chronic inflammation of the small airways leading to airflow limitation and gas trapping, in conjunction with destruction of the lung parenchyma which impairs gas exchange and promotes CO2 retention. Treatment is primarily aimed at alleviating symptoms, as there are currently few therapies that alter the progressive course of the disease. COPD is commonly associated with multiple medical comorbidities, and patients periodically suffer exacerbations during which symptoms acutely worsen, sometimes requiring emergency care or hospitalization. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) provides an evidence-based guide for practitioners to diagnose and treat COPD, which is summarized below.

KEY POINTS:

Diagnosis

Symptoms

Cardinal symptoms
- Persistent dyspnea
- Chronic cough (+/-wheeze)
- Sputum production
Severe disease
- Fatigue
- Weight loss
- Anorexia (associated with poor prognosis)

Spirometry

FEV₁/FVC < 0.70 (post-bronchodilator) confirms diagnosis of COPD
- Should be repeated at least annually in patients with COPD
- Population-based screening spirometry not recommended

Additional Work-Up

Assess exercise impairment (e.g. 6-minute walk test)
Screen all patients with COPD once for alpha-1-antitrypsin deficiency looking for hereditary sources
Differentiating COPD from asthma
- Asthma usually presents with earlier onset
- Asthma symptoms vary widely day-to-day
- Asthma generally associated with allergic rhinitis/eczema (“atopic triad”)

Disease Severity

GOLD Criteria for Classifying Disease Severity

Spirometry alone is insufficient for making individual treatment decisions
- Patients with severe airflow limitation on spirometry may have minimal symptoms (and vice versa)
GOLD grade vs group
- Grade (1-4): Refers to severity of airflow limitation (based on spirometry)
- Group (A-D): Considers patient-reported symptoms and exacerbation risk

Note: Patients with COPD are assigned both a grade and a group

Grade System (1 to 4)

(1-4) for classifying severity of airflow limitation (for patients with FEV₁/FVC <0.70)
- GOLD 1 (mild): FEV₁ ≥80% predicted
- GOLD 2 (moderate): 50% ≤FEV₁<80% predicted
- GOLD 3 (severe): 30% ≤FEV₁<50% predicted
- GOLD 4 (very severe): FEV₁<30% predicted

Group System (A to D)

Assess symptom burden using questionnaires
- Modified Medical Research Council (mMRC): Measures degree of dyspnea
- COPD Assessment Test (CAT): Assesses overall impairment of health in COPD
Record exacerbation risk: Based on number and severity of prior exacerbations

Group System Algorithm for Combined COPD Assessment

0 or 1 exacerbation not leading to hospitalization
- Group A: mMRC 0 to 1 | CAT <10
- Group B: mMRC ≥2 | CAT ≥10
≥2 exacerbations or ≥1 exacerbation leading to hospitalization
- Group C: mMRC 0 to 1 | CAT <10
- Group D: mMRC ≥2 | CAT ≥10

Pharmacologic Therapies

Bronchodilators: B₂-agonists or Anti-Muscarinics

B₂-agonists
- Classified as short-acting (SABA) or long-acting (LABA)
Anti-muscarinics
- Long-acting formulations (LAMA) used for stable COPD (short-acting generally reserved for exacerbations)

Inhaled Corticosteroids (ICS)

Primary benefit is preventing exacerbations
Prescribed in combination with LABA
Greatest benefit: Blood eosinophils > 300 cells/mL
Long-term monotherapy not recommended due to risk for pneumonia, oral thrush, and vocal hoarseness
No benefit of long-term oral glucocorticoids for stable COPD

GOLD group-Based Initial Treatment Recommendations at Time of Diagnosis

GOLD A
- SABA or LABA
GOLD B
- LABA or LAMA
GOLD C
- LAMA
GOLD D
- LAMA
- If highly symptomatic (e.g., CAT >20): LAMA and LABA
- Blood eosinophils > 300 cells/mL: ICS and LABA

Follow-up Pharmacotherapy

If therapy needs to be escalated, first identify if primary issue is persistent dyspnea or frequent exacerbations | Follow exacerbation pathway if both dyspnea and frequent exacerbations are present

For Persistent Dyspnea

Add second bronchodilator (LABA or LAMA)
If already on LABA/ICS, add LAMA (or replace ICS with LAMA)
Consider other causes of dyspnea (e.g. heart failure, anemia)

For Frequent Exacerbations

Add second bronchodilator or ICS
If already on LABA/LAMA
- Blood eosinophils ≥ 100 cells/mL: Escalate to triple therapy (LABA/LAMA/ICS)
- Blood eosinophils < 100 cells/mL: Add roflumilast (for FEV₁ < 50% predicted and chronic bronchitis) or azithromycin (for former smokers) | If already on LABA/ICS: Escalate to triple therapy (LABA/LAMA/ICS)
Consider de-escalation of ICS if
- Pneumonia
- Inappropriate original indication
- Lack of response

Adjunctive Therapies

Smoking cessation (counseling and pharmacotherapy; see ATS guidelines)
Vaccination (influenza and pneumococcal)
Ensure proper inhaler technique
Pulmonary rehabilitation for GOLD groups B through D

Indications for Chronic Oxygen Therapy

PaO2 ≤55 mmHg or SaO2 ≤88% +/-hypercapnia (measured twice over 3 weeks)
PaO2 55 to 60 mmHg if presence of pulmonary hypertension, congestive heart failure, or polycythemia
Oxygen goal: Titrate to SaO2 ≥90%
CPAP or BIPAP
- Long-term non-invasive ventilation may be indicated for patients with severe daytime hypercapnia
- CPAP recommended for patients with comorbid obstructive sleep apnea

Surgical Intervention

Specific subsets of patients may be eligible for bullectomy, lung volume reduction surgery, or lung transplant
Palliative and hospice care should be available for patients with advanced or treatment-resistant symptoms