Abstract
Introduction: Chronic Obstructive Pulmonary Disease (COPD) is confirmed by a FEV1/FVC ratio < 0,7 post bronchodilatator. The measurement of FEV 1 and FVC is performed by forecd spirometry with a minimal expiratory duration of 6s or the presence of a plateau of at least 1s. However, the expiratory duration can increase in COPD patients due to the decrease in pulmonary elastic recoil.
Objectives: In this study we aimed to compare FVC to FEV6 and evaluate reliabilty of FEV1/FEV6 ratio in COPD diagnosis.
Methods: This retrospective study included 86 patients with COPD suspicion adressed to our Pulmonary Function Testing departement to perform forced spirometry. Aside of analysis of clinical and spirometric data of each patient, we compared FVC to FEV6 before and after reversibility test. The Receiver Operator Curve (ROC) analysis was used to look for the cut off value of FEV1/FEV6 ratio to confirm COPD.
Results: The mean age of our population was 60.5 years ± 13.23 with a sex ratio of 0.72. When comparing FVC to VEM6, we found that FVC was higher than VEM6 in 54.7% of patients in baseline spirometry and in 46.5% after reversibility test. This difference was significantly higher in the 64% COPD confirmed patients (p<0.001). Concerning FEV1/FEV6 ratio, the area under curve (AUC) was 0.959 (p < 0.001). The cut-off value with optimal sensitivity (98%) and specificity (97%) was equal to 0.736 with kappa=0.853.
Conclusion: Due to the significant difference between FVC and VEM6 especially in COPD patients, we suggest the prolongation of expiratory duration over 6s as much as possible. In the absence of an expiratory plateau on the volume-time curve, the use of a ratio of FEV1/VEM6 <0.736 would be more accurate.
Footnotes
Cite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA3440.
This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2021