Current situation of asthma-COPD overlap syndrome (ACOS) in Chinese patients older than 40 years with airflow limitation: rationale and design for a multicenter, cross-sectional trial (study protocol).

BACKGROUND

Asthma and chronic obstructive pulmonary disease (COPD) are the frequently occurring chronic airway diseases, and the overlapping syndrome observed in the majority of patients has been recently defined as asthma-COPD overlap syndrome (ACOS) by the Global Initiative for Chronic Obstructive Lung (GOLD, 2014) and Global initiative for Asthma (GINA, 2015). The proportion, features, and clinical practice of ACOS still remain elusive in China. We are conducting this multicenter, cross-sectional, observational study (NCT02600221) to investigate the distributions of chronic obstructive diseases in patients >40 years of age with chronic airflow limitation in China along with determination of the main clinical practice and features of these diseases. The study will also explore the factors that may influence the exacerbations and severity of ACOS in Chinese patients (>40 years of age).

METHODS

A total of 2,000 patients (age, ≥40 years; either sex) who are clinically diagnosed as having asthma, COPD/chronic bronchitis/emphysema, or ACOS for at least 12 months with airflow limitation [post-bronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV/FVC): <0.7] will be enrolled from approximately 20 sites in China between December 2015 and December 2016. The proportion of ACOS among patients older than 40 years based on GINA 2015 and GOLD 2014 definitions is the primary variable. Following were the secondary variables: the proportions of COPD and asthma among the patients, distributions of the severity of airflow limitation, distribution of groups according to GOLD 2011 group definition (A, B, C, D), and the distribution of medication by drug class in patients with ACOS, asthma, and COPD. Acute exacerbation history, hospitalization, and severity of ACOS as evaluated using COPD Assessment Test, Asthma Control Questionnaire-5, and Modified British Medical Research Council in patients with ACOS were also assessed.

IMPLICATIONS

This will be the first study to disseminate scientific knowledge on the current situation, main clinical practice, and features of ACOS, asthma, and COPD conditions in Chinese patients. The insights will be helpful in designing optimal management strategies for ACOS and redefining the healthcare development programs.