Evaluation of Clinical Characteristics and Lung Function Trajectories in Young COPD Patients Within the General Population.

Purpose: Young chronic obstructive pulmonary disease (COPD), distinct from COPD in older individuals, often remains underdiagnosed despite its potential for early interventions. This study aimed to identify the characteristics of young COPD patients and the patterns of lung function trajectory. Patients and Methods: This study was based on a large community-based cohort database in Korea. Young COPD was defined as COPD diagnosed in patients aged ≤ 50 years. We analyzed the clinical characteristics and lung function changes over 12 years, comparing young and old COPD patients. Results: Among the 9,577 patients enrolled in this study, 815 (8.5%) were diagnosed with COPD. The young COPD group had a higher proportion of females, never-smokers and a higher body mass index (BMI), compared to the older COPD group. The prevalence of young COPD increased from 117 (3.64%) to 334 (6.88%) according to the lower limit of normal (LLN) criteria. Analysis of lung function over 12 years revealed that the rate of decline in FEV1 (L), FEF25-75% (L), and FEV1/FVC ratio was slower in young COPD than in old COPD. Multivariate Cox analysis identified female sex, higher FEV1 (%), and young COPD as independent predictive factors for time-to-first normalization of airflow obstruction. Old COPD and low FEV1 (%) were identified as independent risk factors for time-to-first dyspnea. Conclusion: Young COPD is characterized by a higher proportion of females, non-smokers, and elevated BMI compared to old COPD. It has potential for lung function recovery and serves as an independent prognostic factor for the normalization of airflow obstruction.