<p>Clinical Characteristics and Outcomes of Patients with Asthma–COPD Overlap in Japanese Patients with COPD</p>

Abstract

Purpose Asthma–COPD overlap (ACO) has been reported as an association with a lower quality of life, frequent exacerbations, and higher mortality than those with COPD alone. However, clinical characteristics and outcomes of ACO remain controversial. Patients and Methods We conducted a prospective observational study analyzing data of patients with stable COPD enrolled from the Ishinomaki COPD Network Registry. Patients with features of asthma who had a history of respiratory symptoms that vary over time and intensity, together with documented variable expiratory airflow limitation, were identified, and then defined as having ACO. The characteristics, frequency of exacerbations, and mortality during the 3-year follow-up were compared between patients with ACO and patients with COPD alone. Results Among 387 patients with COPD, 41 (10.6%) were identified as having ACO. Patients with ACO tended to be younger, have higher BMI, have a shorter smoking history, and use more respiratory medications, especially inhaled corticosteroids. Inflammatory biomarkers including fractional exhaled nitric oxide, blood eosinophil count, total immunoglobulin E (IgE) level, and presence of antigen-specific IgE were significantly higher in patients with ACO than in those with COPD alone. Lung function, mMRC score, CAT score, and comorbidity index were not different between the groups. The annual rate of all exacerbations and severe exacerbations required hospital admission were not different between ACO and COPD alone (0.20 vs 0.14, 0.12 vs 0.10, events per person, respectively). Mortality was significantly higher in patients with COPD alone compared with those with ACO during the study period (P=0.037). Conclusion The results of our study indicate that ACO is not associated with poor clinical features nor outcomes in an outpatient COPD cohort receiving appropriate treatment.

Update on Asthma–COPD Overlap (ACO): A Narrative Review

“…38 Finally, a Japanese study did not find poor clinical outcomes in patients with ACO receiving appropriate treatment. 44 Clinical differences between ACO, asthma and COPD were more evident in the initial description of ACO cohorts compared with the more recent studies. 22,45,46 Again, this difference may be due to differences in ACO definitions and methodology of the studies.…”

“… 38 Finally, a Japanese study did not find poor clinical outcomes in patients with ACO receiving appropriate treatment. 44 …”

Heterogeneity of asthma–chronic obstructive pulmonary disease (COPD) overlap from a cohort of patients with severe asthma and COPD

“…Patients with ACO extracted from severe asthma cohort showed poor FEV 1 with more frequent exacerbation than the pure severe asthma group. 9 , 10 , 17 However, inconsistent results were reported in the COPD cohort, especially on lung function and the risk of exacerbation 7 , 18 – 23 These differences in outcomes between studies might have resulted from different study populations and criteria used to define ACO. Few studies have been conducted on differences between asthma- and COPD-predominant ACO.…”