What determines severe Chronic Obstructive Pulmonary Disease (COPD)?

From the Guidelines

Severe Chronic Obstructive Pulmonary Disease (COPD) is determined by a forced expiratory volume in one second (FEV1) that is less than 50% of predicted value after bronchodilator use, as well as significant symptoms and history of exacerbations, as outlined in the most recent guidelines 1.

Key Determinants of Severe COPD

The diagnosis and assessment of COPD severity involve several key factors, including:

• Lung function measurements, particularly FEV1 and the FEV1/forced vital capacity (FVC) ratio, which should be less than 0.70 to confirm persistent airflow limitation 1
• Symptom severity, including dyspnea, chronic cough, sputum production, and wheezing
• History of exacerbations, with severe COPD patients typically experiencing frequent exacerbations or hospitalizations

Importance of Spirometry

Spirometry is essential for the diagnosis and assessment of COPD, with the FEV1/FVC ratio being a critical measure of airflow limitation 1. The 2018 GOLD report emphasizes the importance of high-quality spirometry and recommends repeat spirometry for patients with an initial FEV1/FVC ratio in the 0.6 to 0.8 range to account for day-to-day biologic variability.

Severity Assessment and Treatment

The severity assessment of COPD is crucial in guiding treatment decisions, including the use of combination inhalers, oxygen therapy, pulmonary rehabilitation, and evaluation for surgical interventions like lung volume reduction or transplantation 1. The progressive nature of COPD means that severity can worsen over time, particularly with continued exposure to risk factors like smoking or with each significant exacerbation, which can permanently reduce lung function.

Guidelines and Recommendations

The most recent guidelines, such as the 2018 GOLD report 1, provide a framework for the diagnosis, assessment, and management of COPD, including the determination of severe COPD. These guidelines emphasize the importance of a comprehensive approach to COPD management, including lifestyle modifications, pharmacological interventions, and pulmonary rehabilitation.

From the FDA Drug Label

The severity of airflow obstruction at baseline was different among the trials Patients enrolled in the dose selection trials had the full range of COPD severity (FEV 1 30 to 80% predicted); median age of 63 years, 73% male, and 99% Caucasian. Patients enrolled in the four exacerbation trials had severe COPD (FEV 1 ≤50% predicted); median age of 64 years, 74% male, and 90% Caucasian Patients enrolled in the two 6-month efficacy trials had moderate to severe COPD (FEV 1 40 to 70% predicted); median age of 65 years, 68% male, and 97% Caucasian.

Severe Chronic Obstructive Pulmonary Disease (COPD) is determined by a FEV1 ≤50% predicted. This indicates that patients with severe COPD have a significantly reduced lung function, as measured by the forced expiratory volume in one second (FEV1).

• Key factors that determine severe COPD include:
  • FEV1: a measure of lung function, with lower values indicating more severe disease
  • Age: older patients are more likely to have severe COPD
  • Gender: males are more likely to have severe COPD
  • Smoking history: patients with a history of smoking are more likely to have severe COPD 2

From the Research

Determinants of Severe Chronic Obstructive Pulmonary Disease (COPD)

• The severity of COPD is determined by the degree of airflow limitation, which is measured by forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) 3, 4, 5.
• A postbronchodilator FEV1/FVC ratio of 0.7 or less is diagnostic of COPD in a patient with symptoms such as dyspnea, chronic cough, or sputum production, and a history of irritant exposure 4.
• The Global Initiative for Obstructive Lung Disease Workshop Report defines airflow limitation using simple spirometric indices, and categorizes the severity of COPD using FEV1 and FVC, with symptoms playing a minor role in the assessment 3.
• Longitudinal decline in FEV1 is the primary outcome variable for intervention studies aimed at preventing or reducing the loss of pulmonary function 3.

Physiological Measurements and COPD Severity

• Physiological measurements, such as FEV1 and FVC, are important in diagnosing COPD and assessing its severity 3, 5.
• The use of postbronchodilator FEV1/FVC ratio of 0.7 is supported by health-related quality of life measurements 5.
• FEV1 cut-off points of 80,60, and 40% predicted can be used to classify mild, moderate, and severe COPD, respectively 5.

Factors Influencing COPD Severity

• Tobacco smoking is the most significant etiology of COPD, and smoking cessation is the only intervention shown to slow disease progression 4.
• Long-acting beta2-agonists and long-acting muscarinic antagonists are first-line treatments for patients with persistently symptomatic COPD with an FEV1 of 80% or less of predicted 4.
• Combination therapy with a long-acting muscarinic antagonist-long-acting beta2-agonist or long-acting beta2-agonist-inhaled corticosteroid can be prescribed for patients with uncontrolled COPD 4.