How to diagnose asthmatic features in a patient with Chronic Obstructive Pulmonary Disease (COPD)?

From the Guidelines

To diagnose asthmatic features in a patient with Chronic Obstructive Pulmonary Disease (COPD), a stepwise approach is recommended, starting with clinical history, physical examination, and radiology, followed by a syndromic approach to identify features of asthma and COPD, and finally, confirmation with spirometry. This approach is based on the most recent consensus document from the Global Initiative for Asthma (GINA) and the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1. The diagnosis of asthma-COPD overlap syndrome (ACOS) can be made by identifying three or more features of one disease, with features that favor asthma including a history of asthma, atopy, and elevated peripheral blood or sputum eosinophilia.

Key features to look for in diagnosing asthmatic features in COPD patients include:

• A history of asthma
• Significant symptom variability
• Allergic conditions
• Greater reversibility on spirometry testing (improvement in FEV1 ≥12% and ≥200 mL after bronchodilator use)
• Elevated blood eosinophil counts
• Elevated exhaled nitric oxide levels (FeNO ≥20 ppb)

According to the Spanish COPD consensus document, a diagnosis of asthma-COPD overlap can be made with two major criteria (such as an increase in FEV1 ≥15% and ≥400 mL, eosinophilia in sputum, and a history of asthma) or one major and two minor criteria (such as elevated total IgE, history of atopy, and positive bronchodilator response of ≥12% and ≥200 mL) 1. Treatment for patients with asthmatic features typically includes inhaled corticosteroids (ICS) combined with long-acting bronchodilators (LABA), as these patients tend to respond better to anti-inflammatory therapy 1.

The Czech guideline also defines major and minor criteria for the diagnosis of asthma-COPD overlap, including strong bronchodilator test positivity, bronchoconstrictor test positivity, and elevated FeNO or eosinophils in sputum 1. The Australian Asthma Management Handbook recommends pooling of features corresponding to asthma and COPD to make a diagnosis, followed by a trial of ICS and then the addition of LABA for symptom control 1.

In summary, a comprehensive approach to diagnosing asthmatic features in COPD patients involves a combination of clinical evaluation, spirometry, and identification of specific features that favor asthma, with treatment tailored to the individual patient's needs. This approach is supported by the most recent and highest quality evidence from the GINA and GOLD consensus document 1.

From the FDA Drug Label

The diagnosis of COPD was based upon a prior clinical diagnosis of COPD, a smoking history (at least 10 pack-years), age (at least 40 years), and spirometry results (pre-bronchodilator baseline FEV1 at least 30% and less than 70% of the predicted value, and the FEV1/FVC less than 70%) About 58% of patients had bronchodilator reversibility, defined as a 10% or greater increase in FEV1 after inhalation of 2 actuations (180 mcg) of albuterol from a metered dose inhaler.

To diagnose asthmatic features in a patient with Chronic Obstructive Pulmonary Disease (COPD), look for bronchodilator reversibility, defined as a 10% or greater increase in FEV1 after inhalation of a bronchodilator such as albuterol. Key factors to consider include:

• Smoking history: at least 10 pack-years
• Age: at least 40 years
• Spirometry results:
  • Pre-bronchodilator baseline FEV1 at least 30% and less than 70% of the predicted value
  • FEV1/FVC less than 70% 2

From the Research

Diagnosing Asthmatic Features in COPD Patients

To diagnose asthmatic features in a patient with Chronic Obstructive Pulmonary Disease (COPD), the following steps can be taken:

• Identify patients with clinical features of both asthma and COPD, which may represent around 25% of COPD patients and around 20% of asthma patients 3
• Look for non-reversible airflow limitation, significant exposure to smoking or other noxious particles or gases, together with features of asthma 3
• Use postbronchodilator spirometry to confirm a new diagnosis of COPD and prebronchodilator spirometry for the diagnosis of asthma 4
• Evaluate clinical and physiological features, such as dyspnea on exertion, airflow limitation (FEV1), and levels of FENO 5
• Consider the use of multidetector row computed tomography imaging to determine percentage of low attenuation volume, percentage of wall area, and percentage of total cross-sectional area of pulmonary vessels less than 5 mm(2) (%CSA <5) 6

Key Characteristics of Asthma-COPD Overlap

Some key characteristics of asthma-COPD overlap include:

• Airway lesion-dominant phenotype 6
• Higher percentage of wall area and %CSA <5 compared to COPD patients 6
• Increased levels of FENO compared to COPD patients 5
• Higher COPD assessment test scores compared to COPD patients 6
• Significant airflow limitation (FEV1) compared to asthma patients 5

Importance of Accurate Diagnosis

Accurate diagnosis of asthmatic features in COPD patients is crucial for proper therapy and management, as the asthmatic component should be treated with inhaled corticosteroids and some studies suggest that the most severe patients may respond to biological agents indicated for severe asthma 3, 4