The role of FEV1/FVC in the prediction of acute exacerbation of COPD

Background: Whether the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) can be used as a biomarker to predict the risk of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is unclear. Methods: To investigate the predictive role of FEV1/FVC for AECOPD, we analyzed data from an observational and multicenter cohort study of 2043 patients with COPD in KOREA. Exposures were post-bronchodilator FEV1/FVC and/or percentage predicted FEV1 (FEV1%pred). The outcome was the development of AECOPD during the first year of follow-up. Results: During the first year of follow-up, the proportion of patients who developed AECOPD increased as FEV1/FVC decreased (P < 0.01). FEV1/FVC and FEV1%pred had similar predictive power for AECOPD, with optimal predictive cut-offs of approximately 0.5 for FEV1/FVC and 50 % for FEV1%pred. When the participants were classified into groups based on these cut-offs, compared with a high both-lung function group (FEV1/FVC >= 0.5 and FEV1%pred >= 50 %), the low-FEV1 group (FEV1/FVC >= 0.5 and FEV1%pred<50) had a modestly increased risk of severe AECOPD (adjusted odds ratio[aOR] = 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 (FEV1%pred<50 % and FEV1/FVC<0.5) (aOR = 5.16; 95 % CI = 3.34-7.97). Conclusions: FEV1/FVC is a spirometric biomarker predictive of AECOPD. In countries where FEV1%pred is not available for their population, FEV1/FVC could be used as a biomarker for assessing the risk of AECOPD. In countries where accurate FEV1%pred is available, both FEV1%pred and FEV1/FVC could be used to provide additional information to assess the risk of AECOPD. Key message: This study showed that FEV1/FVC had similar predictive power for AECOPD compared with percentage predicted FEV1. Furthermore, the use of both FEV1 and FEV1/FVC provides additional information for the risk assessment of AECOPD.