Abstract
The Korea Chronic Obstructive Pulmonary Disorders Subgroup Study Team (Korea COPD Subgroup Study team, KOCOSS) is a multicenter observational study that includes 956 patients (mean age 69.9 ± 7.8 years) who were enrolled from 45 tertiary and university-affiliated hospitals from December 2011 to October 2014. The initial evaluation for all patients included pulmonary function tests (PFT), 6-minute walk distance (6MWD), COPD Assessment Test (CAT), modified Medical Research Council (mMRC) dyspnea scale, and the COPD-specific version of St. George's Respiratory Questionnaire (SGRQ-C). Here, we report the comparison of baseline characteristics between patients with early- (Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage I and II/groups A and B) and late-stage COPD (GOLD stage III and IV/groups C and D). Among all patients, the mean post-bronchodilator FEV1 was 55.8% ± 16.7% of the predicted value, and most of the patients were in GOLD stage II (520, 56.9%) and group B (399, 42.0%). The number of exacerbations during one year prior to the first visit was significantly lower in patients with early COPD (0.4 vs. 0.9/0.1 vs. 1.2), as were the CAT score (13.9 vs. 18.3/13.5 vs. 18.1), mMRC (1.4 vs. 2.0/1.3 vs.1.9), and SGRQ-C total score (30.4 vs. 42.9/29.1 vs. 42.6) compared to late-stage COPD (all P < 0.001). Common comorbidities among all patients were hypertension (323, 37.7%), diabetes mellitus (139, 14.8%), and depression (207, 23.6%). The data from patients with early COPD will provide important information towards early detection, proper initial management, and design of future studies.