The Characteristics of Airflow Limitation and Future Exacerbations in Different GOLD Groups of COPD Patients

Qing Song,1– 3 Yi-Yang Zhao,1– 3 Yu-Qin Zeng,1– 3 Cong Liu,1– 3 Wei Cheng,1– 3 Min-Hua Deng,4 Xin Li,5 Li-Bing Ma,6 Yan Chen,1– 3 Shan Cai,1– 3 Ping Chen1– 3 1Department of Respiratory and Critical Care Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, People’s Republic of China; 2Research Unit of Respiratory Disease, Central South University, Changsha, Hunan, 410011, People’s Republic of China; 3Diagnosis and Treatment Center of Respiratory Disease, Central South University, Changsha, Hunan, 410011, People’s Republic of China; 4Department of Respiratory, PLA Rocket Force Characteristic Medical Center, Beijing, 100088, People’s Republic of China; 5Division 4 of Occupational Disease, Hunan Occupational Disease Prevention and Treatment Hospital, Changsha, Hunan, 410000, People’s Republic of China; 6Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541000, People’s Republic of ChinaCorrespondence: Ping ChenDepartment of Respiratory and Critical Care Medicine, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Road, Changsha, Hunan, 410011, People’s Republic of ChinaTel +86 731 8529 5248Fax +86 731 8529 5848Email pingchen0731@csu.edu.cnBackground: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 separated pulmonary function from combined assessment. We aimed to analyze the characteristics of airflow limitation and future exacerbations in different GOLD groups of chronic obstructive pulmonary disease (COPD) patients.Methods: For this prospective observational study, stable COPD outpatients were enrolled and divided into Groups A, B, C and D based on GOLD 2017, and followed-up for 18 months. Data on demographics, pulmonary function, COPD assessment test (CAT), Clinical COPD Questionnaire (CCQ), modified Medical Research Council (mMRC), exacerbations, mortality and treatments were collected. A post-bronchodilator ratio of forced expiratory volume in one second to forced vital capacity < 0.70 confirms the presence of airflow limitation.Results: A total of 993 subjects were classified into Groups A (n = 170, 17.1%), B (n = 360, 36.3%), C (n = 122, 12.3%), and D (n = 341, 34.3%). There were significant differences in mMRC, CAT, CCQ, exacerbations and hospitalizations rates among the different groups (P < 0.001). Groups B and D had more severe airflow limitation than Groups A and C (P < 0.05). In the same groups with different severity of airflow limitation, the differences were mainly observed in body mass index, CAT, CCQ and treatment with long-acting muscarinic antagonist (LAMA) and LAMA + long-acting β 2-agonist + inhaled corticosteroid (P < 0.05). After 18 months of follow-up, the exacerbations and hospitalizations rates were significantly different among different groups (P < 0.05). However, in the same groups with different airflow limitation severity, the mortality rates and number of exacerbations, hospitalizations and frequent exacerbators showed no differences.Conclusion: In the GOLD groups, different severity of airflow limitation had no impact on future exacerbations and mortality rate. It implies that pulmonary function is not a good indicator for predicting exacerbation.Keywords: chronic obstructive pulmonary disease, Global Initiative for Chronic Obstructive Lung Disease, pulmonary function, exacerbation