What is COPD (Chronic Obstructive Pulmonary Disease) with asthma features called in the UK?

COPD with Asthma Features in the UK: ASTHMA-COPD OVERLAP SYNDROME (ACOS)

In the UK, COPD with asthma features is officially termed "Asthma-COPD Overlap Syndrome (ACOS)," as recognized by consensus guidelines and the scientific committees of GOLD and GINA. 1

Diagnostic Criteria for ACOS in the UK

ACOS is diagnosed when a patient has the defining characteristic of COPD (incompletely reversible airflow limitation) along with features of asthma. The diagnosis follows a stepwise approach:

1. Recognition of chronic airways disease through:

   • Clinical history
   • Physical examination
   • Radiology
   • Screening questionnaires

2. Syndromic assessment comparing features of asthma and COPD:

   • Three or more features of either asthma or COPD suggests that diagnosis
   • Similar number of features from both conditions suggests ACOS

3. Spirometric confirmation showing:

   • Post-bronchodilator FEV1 < 80% predicted
   • FEV1/FVC ratio < 0.7
   • Incomplete reversibility of airflow limitation

Major and Minor Criteria

According to the Spanish COPD consensus document and Czech guidelines, ACOS can be diagnosed with either:

• Two major criteria:

  • Strong bronchodilator test positivity (FEV1 ≥15% and ≥400 mL)
  • Eosinophilia in sputum
  • History of asthma

• OR one major criterion plus two minor criteria:

  • Elevated total IgE
  • History of atopy
  • Positive bronchodilator response of ≥12% and ≥200 mL on two or more occasions 1, 2

Clinical Characteristics

ACOS patients typically present with:

• Persistent airflow limitation
• Paroxysmal dyspnea, cough, and wheeze that may worsen at night
• Age typically >40 years
• Smoking history
• Previous asthma diagnosis or childhood asthma history 2

Prevalence and Impact

• ACOS affects approximately 20% of patients with obstructive airways diseases 1
• More common in men (69%) in COPD populations
• Mean age of 64.6 years with smoking exposure averaging 38.7 pack-years
• Associated with increased morbidity, more frequent exacerbations, and possibly increased mortality compared to either asthma or COPD alone 1

Treatment Approach in the UK

The UK approach to ACOS treatment follows GINA/GOLD recommendations:

1. Initial therapy: Combination ICS/LABA (inhaled corticosteroid/long-acting beta-agonist) regardless of COPD severity 1, 2

2. As disease progresses: Triple therapy with ICS, LABA, and LAMA (long-acting muscarinic antagonist) 2

3. Treatment adjustments based on:

   • Symptoms
   • Lung function
   • Sputum eosinophilia 2

Clinical Pitfalls and Considerations

• Diagnostic challenges: No single diagnostic test exists for ACOS
• Overreliance on bronchodilator reversibility should be avoided due to lack of reproducibility
• Undertreatment risk: Treating as pure COPD without ICS may lead to inadequate anti-inflammatory therapy 2
• Misclassification risk: Significant proportion of patients may be misclassified, potentially denying appropriate therapy 3

Key Differences from Pure COPD

• ACOS patients have more severe airflow limitation (post-bronchodilator FEV1 of 49.3% predicted)
• Higher bronchodilator reversibility (mean 23.9%)
• May show either eosinophilic or neutrophilic inflammation patterns
• Better response to inhaled corticosteroids than pure COPD 1

The UK approach emphasizes early recognition of ACOS to ensure appropriate treatment with anti-inflammatory therapy, which can significantly impact morbidity, mortality, and quality of life outcomes.