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

Abstract

Background Forced expiratory volume in 1 second (FEV 1 )/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 FEV 1 /FVC decline rate in the Korean general population and to identify whether rapid FEV 1 /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 FEV 1 /FVC decline rate, the most negative FEV 1 /FVC change (1 st quartile of annual FEV 1 /FVC decline rate) was classified as rapid FEV 1 /FVC decline. We investigated the risk of progression to OLD and all-cause and respiratory mortality in individuals with rapid FEV 1 /FVC decline. Results The annual FEV 1 /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 FEV 1 /FVC decline than in those with non-rapid FEV 1 /FVC decline (adjusted incidence rate, 2.119; 95% confidence interval [CI], 1.932–2.324). Rapid FEV 1 /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 FEV 1 /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 FEV 1 /FVC decliners.

Spirometric Interpretation and Clinical Relevance According to Different Reference Equations

“… 11 Additionally, it should be noted that the percentage of predicted value of FEV 1 and FEV 1 /FVC ratio naturally decreases by 1.24% point and 0.32% point, respectively, with age in the general population. 20 21 This suggests that if airway obstruction or airflow limitation is determined based on a conventional fixed value, it can be underestimated in younger individuals and overestimated in older individuals.…”