Current situation of asthma–COPD overlap in Chinese patients older than 40 years with airflow limitation: a multicenter, cross-sectional, non-interventional study

BACKGROUND AND AIMS: Asthma–chronic obstructive pulmonary disease (COPD) overlap (ACO) is poorly recognized in China. Our study determined the distribution of ACO and its clinical characteristics among patients (aged ⩾40 years) with airflow limitation at Chinese tertiary hospitals. METHODS: This cross-sectional, non-interventional study (NCT02600221), conducted between December 2015 and October 2016 in 20 Tier-3 Chinese hospitals, included patients aged ⩾40 years with post-bronchodilator (BD) FEV(1)/FVC <0.7. The primary variable was distribution of ACO in adults with post-BD forced expiratory volume /forced vital capacity (FEV(1)/FVC) <0.7 based on Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2015 and 2017 reports. Other variables included determination of characteristics of ACO and its clinical recognition rate. RESULTS: In 2003 patients (mean age 62.30 ± 9.86 years), distribution of ACO, COPD and asthma were 37.40%, 48.50% and 14.10%, respectively. Proportions of patients with A, B, C and D grouping were 11.70%, 31.00%, 6.90% and 50.30% as per GOLD 2017, whereas they were 15.10%, 51.10%, 3.60% and 30.20% as per GOLD 2015. Similar clinical symptoms were reported in all three groups. A higher percentage of ACO patients presented with dyspnea, wheezing and chest tightness. Compared with the COPD group, a greater proportion of ACO patients reported wheezing (74.6% and 65.40%), while a lower proportion in the ACO group reported cough (79.40% versus 82.70%) and expectoration (76.50% versus 81.60%). Blood eosinophil count ⩾0.3 × 10(9)/L was observed in 34.6% of ACO patients. The clinical recognition rate of ACO was 31.4%. CONCLUSION: Despite ACO affecting two-fifths of the study population, the initial diagnosis rate was low at 6% in China, thus warranting concerted efforts to improve ACO diagnosis. CLINICALTRIALS.GOV: [ClinicalTrials.gov identifier: NCT02600221] registered 22 October 2015, https://clinicaltrials.gov/ct2/show/NCT02600221 The reviews of this paper are available via the supplemental material section.