Asthma-COPD Overlap (ACO)

Background

• Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) is a term used to describe patients demonstrating clinical features of both asthma and COPD. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) recognizes that asthma and COPD are different conditions, even though they may share similar clinical features.
• ACO most commonly affects older adults ≥ 40 years old.
• Prevalence of ACO is about 1.6%-4.5% in general population, and it varies greatly depending on the criteria used to define ACO.
• Patients with ACO generally have more respiratory symptoms, increased risk of exacerbations and hospitalizations, and worse quality of life compared to patients with clinical features of asthma or COPD alone.

Evaluation

• Patients typically have symptoms of chronic airways disease, such as dyspnea, cough, chest tightness, wheezing, and/or sputum production.
• Complete evaluation should involve thorough assessment of medical history and supplemental testing to determine if there are features of asthma and COPD to guide optimal management strategies.
• Suspect ACO in patients with clinical presentations and risk factors of both asthma (such as childhood asthma history, rhinitis, atopic disease) and COPD (such as cigarette smoking, exposure to biomass fuels or air pollution), especially if they are ≥ 40 years old.
• Perform initial testing with spirometry, including forced expiratory volume in 1 second (FEV₁), and FEV₁/forced vital capacity (FEV₁/FVC) ratio, to confirm persistent expiratory airflow limitation and significant bronchodilator reversibility.
• Other testing to determine clinical features of asthma or COPD may include
  • other pulmonary function tests, such as
    • peak expiratory flow (PEF)
    • diffusing capacity of lungs for carbon monoxide (DLCO)
    • fractional exhaled nitric oxide (Fe_NO)
  • arterial blood gas
  • eosinophilia from blood or sputum
  • findings from chest x-ray and high-resolution computed tomography
  • allergy testing with skin prick test and/or immunoglobulin E (IgE) testing

Management

• For patients with clinical features of both asthma and COPD, initial management should follow that of asthma.
• Initial therapy should involve inhaled corticosteroids (ICS), in combination with long-acting beta-2 agonist (LABA) and/or long-acting muscarinic antagonist (LAMA) to reduce risks of severe exacerbations or death.
• Further add-on therapies for patients with moderate or severe asthma or COPD:
  • for patients with elevated IgE or peripheral eosinophilia, anti-IgE or anti-interleukin 5 (IL5) antibodies are an option, including omalizumab, mepolizumab, or benralizumab
  • for patients without elevated IgE or peripheral eosinophilia, options include macrolide antibiotics (such as azithromycin), or phosphodiesterase-4 inhibitors (such as roflumilast)
• For complete management strategies for asthma or COPD, see also
  • Asthma in Adults and Adolescents
  • COPD