Chronic Obstructive Pulmonary Disease (COPD) can develop through a lung function trajectory dominated by an accelerated decline of forced expiratory volume in 1 second (FEV1) from normal maximally attained FEV1 in early adulthood (normal maximally attained FEV1 trajectory), but also through a trajectory with FEV1 below norm in early adulthood (low maximally attained FEV1 trajectory).
To test whether the long-term risk of exacerbations and mortality differs between these two subtypes of COPD.
The cohort included 1170 young adults enrolled in Copenhagen City Heart Study during the 1970s and 1980s. In 2001-3, which served as baseline for present analyses, 79 participants had developed COPD through normal maximally attained FEV1 trajectory, 65 through low maximally attained FEV1 trajectory, and 1026 did not have COPD.
From 2001 until 2018, we observed 139 severe exacerbations of COPD and 215 deaths, of which 55 were due to non-malignant respiratory disease. In Cox models, there was no difference with regard to risk of severe exacerbations between the two trajectories, but individuals with normal maximally attained FEV1 had an increased risk of non-malignant respiratory disease mortality (using inverse probability censoring weighting with adjusted hazard ratio [HR], 6.20; 95% confidence interval [CI], 2.09-18.37; P=0.001) and all-cause mortality (adjusted HR, 1.93; 95% CI, 1.14-3.26; P=0.01) compared to individuals with low maximally attained FEV1.
COPD developed through normal maximally attained FEV1 trajectory is associated with an increased risk of respiratory and all-cause mortality compared to COPD developed through low maximally attained FEV1 trajectory.