Background: Reduced forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC) is a clinically useful index for airflow limitation. Although FEV₁/FVC naturally decreases with age, excess decline of FEV₁/FVC has been reported in some individuals at high-risk. We investigated whether accelerated decline of FEV₁/FVC is related with an increased incidence of chronic obstructive pulmonary disease (COPD) and all-cause or respiratory mortality in general population. Methods: Our observational longitudinal study evaluated subjects in two cohort studies, who had biannual follow-up for up to 18 years. We included the subjects between 40 and 69 years of age who had baseline and follow-up spirometric assessment. Subjects with airflow limitation at baseline were excluded. Based on the quartiles of the annual FEV₁/FVC decline rate, the group with the most negative change in FEV₁/FVC were classified as rapid FEV₁/FVC decliners. Results: In the eligible 7,778 subjects, annual FEV₁/FVC decline rate was 0.32 percentage point/year. Incidence rate of COPD was significantly higher in the subjects with rapid FEV₁/FVC decline (adjusted incidence rate ratio=2.12, 95% confidence interval [CI]=1.93–2.32). Rapid FEV₁/FVC decline was an independent risk factor for all-cause mortality (adjusted hazard ratio [HR]=1.374, 95% CI=1.105–1.709) and respiratory mortality (adjusted HR=1.353, 95% CI=1.089–1.680). Conclusion: Rapid FEV₁/FVC decline may be a potential clinical indicator to find individuals at high risk for development of COPD or mortality in general population. Periodic screening for lung disease may benefit the patients with rapid FEV₁/FVC decline by detecting early COPD.

Rapid FEV1/FVC decline is a risk factor for chronic obstructive pulmonry disease and mortality in general population