Page 88 - Livre électronique des RFTP 2025

P41. FEV1/FEV6 RATIO: A USEFUL TOOL FOR COPD

IDENTIFICATION?

SOUMAYA KHALDI¹⁻², KHOULOUD KCHAOU¹⁻², YOSRA ABDELHEDI¹, CHAIMA
BRIKI¹, NOURELHOUDA BEN MRAD¹, SALOUA BEN KHAMSA JAMELEDDINE¹⁻²

¹ DEPARTMENT OF PHYSIOLOGY AND FUNCTIONAL EXPLORATIONS, ABDERRAHMENE MAMI
HOSPITAL, ARIANA
² LABORATORY OF PHYSIOLOGY, NUTRITION, AND BIOMOLECULES (LR-17-ES-03), BIOTECHNOLOGY
CENTER OF SIDI THABET, UNIVERSITY OF MANOUBA, TUNIS

Background : Spirometry is the gold standard test in obstructive lung diseases as
Chronic Obstructive Pulmonary Disease (COPD), but achieving Forced Vital
Capacity (FVC) can be challenging for some patients. Forced Expiratory Volume in
6 s (FEV6) has emerged as a potential alternative, requiring less effort while
maintaining diagnostic accuracy.

Aim : To determine a fixed cut off of the FEV1/FEV6 ratio to diagnose COPD
corresponding to a post-bronchodilator FEV1/FVC < 70% as recommended by
GOLD guidelines.

Method : It was a cross-sectional study including 84 male smokers suspected of
having COPD, referred for pulmonary function testing. We analyzed Forced
Expiratory Volume in 1 s (FEV1%) before and after bronchodilation, FEV6%, FVC%,
and dyspnea (mMRC-score). The diagnostic performance of the FEV1/FEV6 ratio in
identifying COPD was evaluated using a Receiver Operating Characteristic (ROC)
curve, with an optimal cut-off determined based on sensitivity and specificity.

Results : The mean age was 62.06±8.68 years. The mean tobacco consumption was
48.42±34.351 pack-year. The mean post-bronchodilator FEV1/FVC ratio and
FEV1/FEV6 were 58.81±15.49%, and 55.58±11.36%, respectively. In the study
population, 69% of the patients had COPD (post-bronchodilator FEV1/FVC ratio <
70%) and 31% were healthy smokers. A strong correlation was observed between
the post-bronchodilator ratio FEV1/FVC and FEV1/FEV6 (r= 0.931, p<0.001). The
ROC curve analysis identified an optimal cutoff value for the FEV1/FEV6 ratio at
48.99, which allowed for the identification of patients with COPD. At this threshold,
the sensitivity and specificity of the FEV1/FEV6 ratio were 100% and 99.9%,
respectively.

(Note: The conclusion in the original OCR for P41 contains "A cut-off of FEV1/FEV6 <
72.68%...". This seems contradictory to the result finding an optimal cutoff at 48.99. I will
include the conclusion as written in the OCR, but point out this potential discrepancy if
needed for clarification.)

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