Rapid FEV₁/FVC Decline Is Related With Incidence of Obstructive Lung Disease and Mortality in General Population

BACKGROUND: Forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) naturally decreases with age; however, an excessive decline may be related with increased morbidity and mortality. This study aimed to evaluate the FEV1/FVC decline rate in the Korean general population and to identify whether rapid FEV1/FVC decline is a risk factor for obstructive lung disease (OLD) and all-cause and respiratory mortality. METHODS: We evaluated individuals aged 40-69 years who underwent baseline and biannual follow-up spirometric assessments for up to 18 years, excluding those with airflow limitations at baseline. Based on the quartiles of the annual FEV1/FVC decline rate, the most negative FEV1/FVC change (1st quartile of annual FEV1/FVC decline rate) was classified as rapid FEV1/FVC decline. We investigated the risk of progression to OLD and all-cause and respiratory mortality in individuals with rapid FEV1/FVC decline. RESULTS: The annual FEV1/FVC decline rate in the eligible 7,768 patients was 0.32 percentage point/year. The incidence rate of OLD was significantly higher in patients with rapid FEV1/FVC decline than in those with non-rapid FEV1/FVC decline (adjusted incidence rate, 2.119; 95% confidence interval [CI], 1.932-2.324). Rapid FEV1/FVC decline was an independent risk factor for all-cause mortality (adjusted hazard [HR], 1.374; 95% CI, 1.105-1.709) and respiratory mortality (adjusted HR, 1.353; 95% CI, 1.089-1.680). CONCLUSION: The annual FEV1/FVC decline rate was 0.32%p in the general population in Korea. The incidence rate of OLD and the hazards of all-cause and respiratory mortality were increased in rapid FEV1/FVC decliners.