Clinical Characteristics of Individuals with COPD, Pre-COPD, Smokers with Normal Lung Function in Korea: Updated Analysis of the KOCOSS Cohort.

Background: Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung disease characterized by persistent airflow limitation and is a leading cause of mortality worldwide. Pre-COPD refers to a pre-disease state associated with an increased risk of COPD development. This study aims to evaluate the clinical characteristics of individuals with COPD, pre-COPD, and smokers with normal lung function in South Korea, and to provide an updated analysis of the KOCOSS cohort data.

Methods: We analyzed data from 4,502 participants in the KOCOSS database collected between 2012 and 2025, including 4,197 with COPD, 126 with pre-COPD, and 179 smokers with normal lung function. Baseline characteristics were compared across these groups.

Results: Patients with COPD were more likely to be male, older, and had a lower body mass index than those with pre-COPD and smokers with normal lung function. Symptom burden, as assessed by the COPD Assessment Test and modified Medical Research Council dyspnea scale, was highest in patients with COPD, followed by pre-COPD and smokers with normal lung function. Patients with COPD had the highest overall use of respiratory medications (89.3%), including inhalers and other treatments, followed by pre-COPD individuals (61.5%) and smokers with normal lung function (47.4%). Hypertension was the most common comorbidity across all groups, with no significant differences in the prevalence of comorbidities.

Conclusion: This analysis of the KOCOSS cohort highlights the distinct clinical characteristics of individuals with COPD, pre-COPD, and smokers with normal lung function. Notably, individuals without spirometric COPD still showed substantial symptom burden and inhaler use.