What is COPD (Chronic Obstructive Pulmonary Disease) with asthma responsive features?

COPD with Asthma Responsive Features: Definition and Clinical Approach

COPD with asthma responsive features refers to patients who have the defining characteristics of COPD (incompletely reversible airflow limitation) along with specific features of asthma, creating a phenotype that may benefit from targeted treatment approaches including inhaled corticosteroids. 1

Diagnostic Criteria

The identification of COPD with asthma responsive features involves recognizing specific clinical and physiological characteristics:

Major Criteria

• Incompletely reversible airflow limitation (post-bronchodilator FEV1 <80% predicted and FEV1/FVC <0.7) 1
• Strong bronchodilator test positivity (FEV1 increase >15% and >400 mL) 1
• Sputum eosinophilia (≥3%) or elevated blood eosinophils (≥300 cells/μL) 1, 2
• History of asthma diagnosis, particularly before age 40 1

Minor Criteria

• Mild bronchodilator test positivity (FEV1 increase >12% and >200 mL) 1
• Elevated total IgE 1
• History of atopy 1

According to the Spanish COPD consensus and Czech guidelines, this phenotype can be confirmed by either two major criteria or one major plus two minor criteria 1.

Pathophysiological Features

COPD with asthma responsive features represents a unique inflammatory pattern that combines elements of both diseases:

• Mixed inflammatory pattern with both neutrophilic (typical of COPD) and eosinophilic (typical of asthma) components 3, 4
• Airway remodeling that may differ from pure COPD or asthma 3
• Persistent but partially reversible airflow limitation 5
• Affects approximately 25% of patients with COPD and nearly one-third of patients with a history of asthma 6, 4

Clinical Presentation

Patients with this phenotype typically present with:

• Age >40 years with smoking history or exposure to noxious particles 5
• Persistent airflow limitation with some degree of reversibility 1
• Paroxysmal dyspnea, cough, and wheeze that may worsen at night 1
• More frequent and severe exacerbations compared to patients with COPD alone 5, 4
• Poorer quality of life and increased risk of hospitalizations 4

Limitations of Bronchodilator Reversibility Testing

It's important to note that bronchodilator reversibility (BDR) has limitations in identifying this phenotype:

• BDR is not reproducible in COPD patients 1
• BDR does not consistently relate to other asthma features 1
• BDR does not reliably predict inhaled corticosteroid (ICS) responsiveness 1
• BDR represents "phenotype mimicry" rather than a definitive diagnostic feature 1

Treatment Implications

The identification of asthma features in COPD has significant treatment implications:

• Inhaled corticosteroids (ICS) should be included in the treatment regimen regardless of COPD severity 1
• Combination therapy with ICS plus long-acting beta-agonist (LABA) is recommended 1
• Triple therapy with ICS, LABA, and long-acting muscarinic antagonist (LAMA) may be needed as disease severity increases 1
• Treatment may be adjusted according to symptoms, lung function, and sputum eosinophilia 1
• Patients with significant eosinophilia may potentially benefit from biological agents in the future 2

Clinical Pitfalls to Avoid

1. Overreliance on bronchodilator reversibility: While reversibility testing is included in diagnostic criteria, it should not be the sole determinant due to its limitations in reproducibility and predictive value 1.

2. Treating as pure COPD without ICS: Failing to recognize asthmatic features may lead to undertreatment without appropriate anti-inflammatory therapy 1.

3. Treating all COPD patients with ICS: Not all COPD patients have asthmatic features, and unnecessary ICS use may increase pneumonia risk in those without eosinophilic inflammation.

4. Ignoring the heterogeneity within this phenotype: The overlap category includes patients with diverse characteristics who may respond differently to treatments 2.

The concept of COPD with asthma responsive features represents an important clinical entity that requires recognition and appropriate management to optimize outcomes and reduce the burden of symptoms and exacerbations in affected patients.