The characteristics of airflow obstruction and its association with treatment response in the real world in different GOLD groups of COPD patients

Abstract Background: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 separated spirometry from combined assessment to guide treatment. We aimed to analyze the characteristics of airflow obstruction and its association with treatment response in the real world in different GOLD groups of 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 patient demographics, pulmonary function, COPD assessment test (CAT), Clinical COPD Questionnaire (CCQ), modified Medical Research Council (mMRC), exacerbations, mortality and treatments were collected to analyze the airflow obstruction and its association with treatment response. 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 among different groups (P < 0.001). Groups B and D had more airflow obstruction and ventilatory disorder than Groups A and C (P < 0.05). In the same groups with different GOLD grades, the differences were mainly observed in BMI, CAT, CCQ and treatment with long-acting muscarinic antagonist (LAMA) and LAMA + long-acting β2-agonist (LABA) + inhaled corticosteroid (ICS) (P < 0.05). After 18 months of follow-up, the number of exacerbations and hospitalizations were significantly different among different groups, with Group D having the highest values. Also, there were more frequent exacerbators and a higher mortality rate in Group D. However, in the same groups with different GOLD grades, the mortality rates and number of exacerbations, hospitalizations and frequent exacerbators showed no differences. Conclusion: There were significant differences in pulmonary function in different groups. However, different GOLD grades had no impact on future exacerbations and mortality rate in the same groups.