The Role of FEV1/FVC in the Prediction of Acute Exacerbation of COPD

Abstract

Abstract Background: Whether the ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) can be used as a spirometric biomarker to predict future risks of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is unknown. This study evaluated whether reduced FEV1/FVC is associated with an increased risk of AECOPD and whether that risk is further increased when both FEV1/FVC and the percentage of predicted FEV1 (FEV1 %pred) are decreased. Methods: Data from a prospective observational and multicenter cohort study of 2,043 patients in Korea with chronic obstructive pulmonary disease were analyzed. The exposures were post-bronchodilator (BD) FEV1/FVC and/or FEV1%pred. The main outcome was AECOPD during the first year of follow-up. Results: The incidence rate of AECOPD increased as post-BD FEV1/FVC decreased (P < 0.001). Post-BD FEV1/FVC and FEV1 %pred had similar predictive powers for AECOPD, with optimal predictive cut-offs of approximately 0.5 for post-BD FEV1/FVC and 50%pred for FEV1. When the participants were classified into groups based on these cut-off values, compared with a high both-lung function group (post-BD FEV1/FVC ≥ 0.5 and FEV1 ≥ 50%pred), the low-FEV1 group (post-BD FEV1/FVC ≥ 0.5 and FEV1 < 50%pred) had a modestly increased risk of severe AECOPD (adjusted hazard ratio [aHR] = 3.12, 95% confidence interval [CI] = 1.59–6.16), while the risk of severe AECOPD was the highest in the low both-lung function group (aHR = 5.16, 95% CI = 3.34–7.97) (FEV1 < 50%pred and post-BD FEV1/FVC < 0.5). Conclusion: Post-BD FEV1/FVC is a spirometric biomarker predictive of AECOPD. In countries where accurate FEV1 %pred is not available for their population, post-BD FEV1/FVC could be used as an alternative biomarker to assess the future risk of AECOPD. In countries where accurate FEV1 %pred is available, both FEV1 %pred and post-BD FEV1/FVC could be used to provide additional information for assessments of the future risk of AECOPD.