Current Evidence of Treatment for Asthma-COPD Overlap (ACO): Is There Emerging Evidence of Optimal Therapy?—In Asthma COPD Overlap: Updated Concept, Pathophysiology, Diagnosis and Treatment

Asthma-COPD overlap (ACO), a phenotype involving asthma and COPD, is an important disease entity because patients with ACO have significantly worse outcomes, conferring greater economic and social burdens. Some guidelines for ACO recommend add-on therapy of long-acting muscarinic antagonists (LAMAs) to inhaled corticosteroids (ICS) and long-acting β2 agonists (LABAs). However, this approach is based on extrapolation from patients with asthma or COPD alone. Therefore, there is still no consensus on the treatment strategy for ACO based on sufficient evidence. When ACO is diagnosed for the first time, the severity of asthma and COPD is determined. The more severe severity of each is used as a reference. The following treatment is recommended: ICS+LABA, ICS+LABA, and ICS+LABA+LAMA starting from the mildest disease, followed by theophylline, leukotriene receptor antagonist, anti-IgE antibody, anti-IL5 antibody, oral steroids, and in cases of high sputum production, macrolides, and expectorants, etc., are added sequentially when sputum production is increased. The degree of exacerbation of ACO is classified into three categories: mild, moderate, and severe. Mild disease presents with mild dyspnea and wheezing attacks, and inhalation of a short-acting β2 agonist (SABA) is recommended for asthma and COPD, as is the case for ACO. If the patient has been treated with budesonide/formoterol in the stable phase, this drug can also treat attacks. If SABA inhalation or additional budesonide/formoterol inhalation fails to improve, i.e., moderate or severe exacerbations, systemic administration of steroids has to be indicated.