COPD, Asthma, or Asthma COPD Overlap Syndrome: Diagnostic Challenges

Chronic obstructive pulmonary disease (COPD) and adult-onset asthma often have overlapping symptoms. This condition has recently been named asthma-COPD overlap syndrome (ACO) and it occurs in up to 20% of patients.¹ Although treatment for both disorders includes long-acting beta-2-agonist (LABA) bronchodilators and inhaled corticosteroids (ICS), the medications must be used differently according to the respective diagnoses. An estimated 50% of adults with COPD are either misdiagnosed or underdiagnosed.¹ A misdiagnosis can result in serious adverse effects and wastes health resources.¹ 

Evaluate Carefully, Reevaluate Often

In patients with COPD, tobacco smoke or environmental exposures are likely to result in dyspnea, chronic cough, or sputum production. Clinicians, however, should diagnose COPD based on postbronchodilator spirometry results.¹

In some cases, COPD diagnoses have been reversed when patients stopped smoking, and therefore, follow-up spirometry is essential to ascertain the correct diagnosis.¹ A Canadian study (N=1551) found that COPD diagnosis reversals were as high as 27%, especially in patients who quit smoking and whose baseline forced expiratory volume in 1 second/forced vital capacity level was near the diagnostic threshold.²  

Bronchodilators are recommended as first-line therapy for COPD, regardless of Global Initiative for Chronic Obstructive Lung Disease (GOLD) disease severity classification. Patients with minimal COPD symptoms (classified as GOLD group A) should receive short- or long-acting bronchodilator therapy; those with moderate symptoms (GOLD groups B and C) should use a LABA. Unlike patients with asthma, patients with COPD should not use ICS as monotherapy because it can lead to serious adverse effects such as pneumonia as a result of changes in the lung microbiome.¹ In older patients with COPD, ICS use can lead to bruising, skin thinning, bone fractures, and elevated blood glucose levels.¹

Dyspnea, wheezing, variable cough, and chest tightness are the hallmarks of asthma. Asthma usually presents in early childhood, but it may appear in adulthood. Lung function tests determine airflow limitations, and like COPD assessments, need to be readministered periodically.¹ The initial recommended therapy is ICS, and depending on the symptoms, ICS may be combined with LABAs.¹

The Global Initiative for Asthma and GOLD have proposed ACO diagnosis guidelines.³ Like asthma and COPD, ACO includes airflow limitations, but the organizations have not yet defined exactly what ACO entails because of limited evidence. In the absence of formal guidelines, the organizations’ consensus recommendations for therapy include ICS, depending on symptom severity, and adding treatment with a LABA or long-acting muscarinic antagonist.³

Asthma Diagnosis Reversals

The importance of frequent reassessments for patients with asthma is underscored by a Canadian study in which researchers reevaluated asthma diagnosis in 613 participants and were able to rule out asthma in 203 (33.1%; 95% CI, 29.4%-36.8%).⁴ In addition, 2% of patients had serious cardiorespiratory disease (eg, ischemic heart disease, subglottic stenosis, pulmonary hypertension) that had been misdiagnosed as asthma. At the 12-month follow-up, 29.5% of the reevaluated patients (n=181) did not have any clinical or laboratory evidence of asthma (95% CI, 25.9%-33.1%).⁴