Characteristics of Specialist-Diagnosed Asthma-COPD Overlap in Severe Asthma: Observations from the Korean Severe Asthma Registry (KoSAR)

Abstract

BACKGROUND: While the clinical characteristics and outcomes of asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) have been frequently compared with those of COPD or asthma, the prevalence and features of ACO in patients with severe asthma are unclear. <br>OBJECTIVES: Evaluation of the prevalence and clinical features of ACO using the Korean severe asthma registry. <br>METHODS: At the time of registration, ACO was determined in patients with severe asthma by attending specialists. Patients were classified into ACO and non-ACO groups, and the demographic and clinical characteristics of these two groups were compared. <br>RESULTS: Of 482 patients with severe asthma, 23.7% had ACO. Patients in the ACO group were more likely to be male (P &lt; .001), older (P &lt; .001), and ex- or current smokers (P &lt; .001) compared with those in the non-ACO group. Patients in the ACO group had lower mean forced expiratory volume in 1 second (P &lt; .001) and blood eosinophil percentage (P = .006), but higher blood neutrophil percentage (P = .027) than those in the non-ACO group. The ACO group used more inhaled long-acting muscarinic antagonist (P &lt; .001), methylxanthine (P = .001), or sustained systemic corticosteroid (P = .002). In addition, unscheduled emergency department visits due to exacerbation were more frequent in the ACO group (P = .006). <br>CONCLUSION: Among patients with severe asthma, those with ACO were older, predominantly male, and were more likely to have a smoking history than those with asthma only. Patients with ACO used more systemic corticosteroid and had more frequent exacerbations related to emergency department visits than those with severe asthma only.