What is the classification and treatment of Chronic Obstructive Pulmonary Disease (COPD)?

COPD Classification and Treatment

COPD is classified based on airflow limitation severity, symptoms, and exacerbation history, with treatment now primarily guided by symptom burden and exacerbation risk rather than spirometric staging alone. 1

Diagnosis of COPD

COPD diagnosis requires three essential elements:

• Post-bronchodilator FEV1/FVC ratio <0.70 (confirming persistent airflow limitation)
• Appropriate symptoms (dyspnea, chronic cough, sputum production, or wheezing)
• Significant exposure to noxious stimuli (typically smoking or environmental exposures) 1

For borderline cases with FEV1/FVC ratio between 0.6-0.8, repeat spirometry is recommended to account for day-to-day biological variability 1.

Classification Systems

Spirometric Classification

The severity of airflow obstruction is categorized as:

Severity	Post-bronchodilator FEV1/FVC	FEV1 % predicted
At risk*	>0.7	≥80
Mild COPD	≤0.7	≥80
Moderate COPD	≤0.7	50-80
Severe COPD	≤0.7	30-50
Very severe COPD	≤0.7	<30

*At risk: patients who smoke/have pollutant exposure, have respiratory symptoms, or family history of chronic respiratory disease 1

GOLD ABCD Assessment Tool

The 2017/2018 GOLD update shifted from using spirometric staging alone to guide treatment intensity, now focusing on:

1. Symptom burden (using mMRC dyspnea scale or CAT score)
2. Exacerbation history 1

This creates four patient groups:

• 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 1

High symptoms are defined as:

• mMRC dyspnea score ≥2, or
• CAT score ≥10 1

High exacerbation risk is defined as:

• ≥2 exacerbations in the preceding year, or
• ≥1 hospitalization for exacerbation 1

Composite Prognostic Indices

Several multidimensional assessment tools provide better prognostic information than FEV1 alone:

• BODE: BMI, airflow Obstruction, Dyspnea, Exercise capacity
• mBODE: Modified BODE (replaces 6MWD with peak oxygen consumption)
• BODEx: BMI, airflow Obstruction, Dyspnea, Exacerbation rate
• ADO: Age, Dyspnea, airflow Obstruction
• DOSE: Dyspnea, airflow Obstruction, Smoking status, Exacerbation rate
• CODEx: Comorbidity, Obstruction, Dyspnea, previous severe Exacerbations 1

Treatment Approach

Non-Pharmacological Treatment

For all COPD patients:

• Smoking cessation (most important intervention) 2
• Pulmonary rehabilitation 2
• Vaccinations (influenza, pneumococcal) 1
• Physical activity 1

Pharmacological Treatment

Treatment is guided by the ABCD assessment:

1. Group A (Low symptoms, Low risk):

   • Short-acting bronchodilator as needed 1

2. Group B (High symptoms, Low risk):

   • Long-acting bronchodilator (LABA or LAMA) 1
   • Consider second bronchodilator if symptoms persist

3. Group C (Low symptoms, High risk):

   • LAMA preferred 1

4. Group D (High symptoms, High risk):

   • LAMA or LAMA+LABA 1
   • Consider LABA+ICS if features of asthma or high blood eosinophil counts
   • Consider triple therapy (LABA+LAMA+ICS) for persistent exacerbations 1, 3

Exacerbation Management

Exacerbations are classified as:

• Mild: Treated with short-acting bronchodilators only
• Moderate: Treated with short-acting bronchodilators plus antibiotics and/or oral corticosteroids
• Severe: Requires hospitalization or emergency room visit 1

Treatment includes:

• Short-acting inhaled β2-agonists with or without short-acting anticholinergics
• Systemic corticosteroids (improve lung function and shorten recovery time)
• Antibiotics when indicated (purulent sputum)
• Non-invasive ventilation for respiratory failure 1

Important Clinical Considerations

• There is significant discordance between symptom assessment tools (mMRC vs CAT), with a CAT score of 17 showing better specificity for identifying patients with mMRC ≥2 4
• The 2017/2018 GOLD reclassification resulted in many former Group D patients moving to Group B, making Group B more heterogeneous with higher exacerbation risk 5
• Comorbidities significantly contribute to COPD severity and mortality - most patients die of lung cancer or heart disease rather than COPD itself 1
• COPD is commonly both overdiagnosed and underdiagnosed due to lack of spirometry testing 1

Treatment Pitfalls to Avoid

• Relying solely on spirometry for treatment decisions (the current GOLD approach focuses on symptoms and exacerbation history) 1
• Using higher doses of ICS than necessary (increased risk of pneumonia) 3
• Failing to address comorbidities that impact COPD outcomes 1
• Not recognizing that COPD exacerbations may be precipitated by cardiovascular events, pulmonary embolism, or pneumonia 1
• Overuse of inhaled corticosteroids in patients without frequent exacerbations or asthmatic features 1