High prevalence of previously undiagnosed COPD in individuals undergoing lung cancer screening in Korea.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) remains substantially underdiagnosed, particularly in individuals with mild or early-stage disease. Individuals undergoing lung cancer screening represent a high-risk population due to significant smoking exposure; however, the burden of previously undiagnosed COPD in this real-world clinical setting remains insufficiently characterized. METHODS: This retrospective observational study included individuals who underwent national lung cancer screening using low-dose computed tomography (LDCT) at a tertiary referral center between September 2019 and December 2022. The study population consisted of individuals referred for pulmonologist consultation after screening, reflecting real-world clinical practice. Participants without a prior diagnosis of COPD who underwent pulmonary function testing were included. Clinical characteristics, pulmonary function parameters, and CT findings were analyzed. Multivariable logistic regression analysis was performed to identify factors associated with previously undiagnosed COPD. RESULTS: Among 279 individuals who underwent pulmonologist consultation, 170 had available spirometry and were included in the analysis. Of these, 63 individuals (37.1%) met spirometric criteria for COPD despite having no prior diagnosis. Participants with previously undiagnosed COPD were more likely to report dyspnea and demonstrated greater physiologic impairment and structural lung abnormalities, including a trend toward lower diffusion capacity and CT-defined emphysema. In multivariable analysis, dyspnea, reduced DLCO, and CT-defined emphysema were independently associated with COPD. CONCLUSIONS: A substantial proportion of individuals undergoing lung cancer screening were found to have previously undiagnosed COPD. These findings highlight a gap in real-world screening workflows and support the potential value of integrating spirometry or respiratory assessment into lung cancer screening programs to facilitate early detection and timely management of COPD in high-risk populations.