Clinical Characteristics and Frequency of Chronic Obstructive Pulmonary Disease Exacerbations in Korean Patients: Findings From the KOCOSS Cohort 2012-2021

Abstract

Background: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) exert a substantial burden on patients and healthcare systems; however, data related to the frequency of AECOPD in the Korean population are limited. Therefore, this study aimed to describe the frequency of severe, and moderate or severe AECOPD, as well as clinical and demographic characteristics of patients with chronic obstructive pulmonary disease (COPD) in South Korea.

Methods: Data from patients aged > 40 years with post-bronchodilator forced expiratory volume in 1 second (FEV₁)/forced vital capacity ≤ 70% of the normal predicted value from the Korea COPD Subgroup Study database were analyzed (April 2012 to 2021). The protocol was based on the EXAcerbations of COPD and their OutcomeS International study. Data were collected retrospectively for year 0 (0-12 months before study enrollment) based on patient recall, and prospectively during years 1, 2, and 3 (0-12, 13-24, and 25-36 months after study enrollment, respectively). The data were summarized using descriptive statistics.

Results: Data from 3,477 Korean patients (mean age, 68.5 years) with COPD were analyzed. Overall, most patients were male (92.3%), former or current smokers (90.8%), had a modified Medical Research Council dyspnea scale score ≥ 1 (83.3%), and had moderate airflow limitation (54.4%). The mean body mass index (BMI) of the study population was 23.1 kg/m², and 27.6% were obese or overweight. Hypertension was the most common comorbidity (37.6%). The mean blood eosinophil count was 226.8 cells/μL, with 21.9% of patients having ≥ 300 cells/μL. A clinically insignificant change in FEV₁ (+1.4%) was observed a year after enrollment. Overall, patients experienced a mean of 0.2 severe annual AECOPD and approximately 1.1 mean moderate or severe AECOPD. Notably, the rates of severe AECOPD remained generally consistent over time. Compared with patients with no exacerbations, patients who experienced severe exacerbations had a lower mean BMI (21.7 vs. 23.1 kg/m²; P < 0.001) and lower lung function parameters (all P values < 0.001), but reported high rates of depression (25.5% vs. 15.1%; P = 0.044) and anxiety (37.3% vs. 16.7%; P < 0.001) as a comorbidity.

Conclusion: Findings from this Korean cohort of patients with COPD indicated a high exacerbation burden, which may be attributable to the unique characteristics of the study population and suboptimal disease management. This highlights the need to align clinical practices with the latest treatment recommendations to alleviate AECOPD burden in Korea.

Trial registration: ClinicalTrials.gov Identifier: NCT05750810.

Keywords: Chronic Obstructive Pulmonary Disease; Exacerbation; KOCOSS Cohort; Registries; Respiratory Function Tests; South Korea.

Fig. 1. Change in FEV1 according to BEC and exacerbation. (A) Change in FEV₁ between years 0–3 and (B) decline in FEV₁ between year 1 and year 3 in Korean patients with COPD from the KOCOSS cohort based on blood eosinophil counts (< 300 vs. ≥ 300 cells/μL), and a history of exacerbations. BEC < 300 cells/μL without exacerbations (n = 114); BEC ≥ 300 cells/μL without exacerbations (n = 35); BEC < 300 cells/μL with exacerbations (n = 83); BEC ≥ 300 cells/μL with exacerbations (n = 36).

BEC = blood eosinophil count, FEV₁ = forced expiratory volume in 1 second, COPD = chronic obstructive pulmonary disease, KOCOSS = Korea COPD Subgroup Study.