To analyzing and comparing the clinical features of asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) with asthma and COPD to promote the early diagnosis and treatment of ACO.

A total of 140 patients with either COPD or asthma hospitalized in the First Affiliated Hospital of Nanjing Medical University from 2014 to 2018 were recruited, divided into three groups: ACO group (40 cases), asthma group (50 cases), and COPD group (50 cases). The differences of demographic characteristics, laboratory examinations, imaging features, lung functions and hospitalization conditions among the three groups were analyzed to evaluate the feasibility of initially screening ACO patients from those with asthma or COPD by clinical data.

The mean age and proportion of smokers of ACO group were higher than asthma group (P<0.01) and lower than COPD group (P<0.01).17.5% patients with ACO had blood eosinophils ≥300/μl, and 55% patients with ACO showed elevated serum total IgE, both significantly higher than COPD group (P<0.05).47.5% patients with ACO showed elevated blood neutrophils, and 22.5% patients with ACO showed elevated C-reactionprotein(CRP), both significantly higher than asthma group (P<0.05). The average values of forced exhalation volume in the first second (FEV₁)/FVC (FEV₁/FVC), forced exhalation volume in the first second per predicted (FEV₁%pred), peak expiratory flow per predicted and diffusing capacity of the lung for carbon monoxide per predicted of ACO group were lower than those of asthma group respectively (P<0.05). Resistor variable/total lung capacity per predicted of ACO group was significantly higher than that of asthma group (P<0.05), but lower than that of COPD group (P<0.01). The duration of oral glucocorticoids in ACO group was significantly longer than that of COPD group (P<0.05), and the proportion of using inhaled glucocorticoids (97.5%) was significantly higher than that of COPD group (P<0.01), while the duration of using antibiotics showed no significant difference from that of COPD group (P>0.05). By comprehensive analysis of age, smoking history, blood neutrophils and chest CT features, the sensitivity and specificity of differentiating ACO from asthma were calculated to be 90% and 76% respectively.By comprehensive analysis of gender, smoking history, allergy history, blood eosinophils and serum total IgE, the sensitivity and specificity of differentiating ACO from COPD were calculated to be 70% and 76% respectively.

ACO has its own unique features, although there are many clinical manifestations similar to asthma and COPD.It is beneficial for identifying ACO from asthma or COPD preliminarily by means of comprehensive analysis of clinical data.

Asthma-chronic obstructive pulmonary disease overlap; Asthma; Pulmonary disease, chronic obstructive; Clinical features