Heterogeneous lung function trajectories in individuals with newly diagnosed COPD after referral from lung cancer screening: a real-world longitudinal study

Longitudinal changes in lung function in individuals with COPD newly diagnosed after referral from lung cancer screening have not been well characterized. We aimed to evaluate the trajectory of lung function decline and explore factors associated with accelerated decline in this group of COPD patients. This retrospective observational study included individuals who were referred for consultation with a pulmonologist after lung cancer screening and had available follow-up spirometry at a tertiary referral center. All participants had baseline post-bronchodilator airflow obstruction (FEV 1 /FVC < 0.70) and no prior diagnosis of COPD. Annual changes in forced expiratory volume in 1 s (FEV 1 ) were calculated. Extreme values exceeding ± 0.3 L/year were excluded. Rapid decliners were defined as individuals with an annual FEV 1 decline > 60 mL/year. Clinical characteristics, pulmonary function parameters, and radiologic findings were compared between rapid and non-rapid decliners. A total of 33 individuals were included after exclusion of outliers. The mean annual FEV 1 change was − 0.02 ± 0.09 L/year, demonstrating considerable variability across individuals. Eleven of the 33 participants (33.3%) were classified as rapid FEV 1 decliners. Baseline FEV 1 was significantly higher in rapid decliners than in non-rapid decliners, whereas no other baseline clinical characteristics differed significantly between the groups. Lung function trajectories among individuals with COPD newly diagnosed after referral from lung cancer screening were heterogeneous, with a subset demonstrating rapid decline. Although no clear predictors of rapid decline were identified, longitudinal assessment may provide additional insights beyond cross-sectional evaluation in this population. Larger prospective studies are warranted to better define risk factors for accelerated lung function decline.