Page 62 - Livre électronique des RFTP 2025

P19. RESTING INSPIRATORY CAPACITY TO VITAL

CAPACITY RATIO PREDICTS EXACERBATIONS IN COPD

CHAIMA BRIKI, KHOULOUD KCHAOU, SALMA BOUSLAMA, SOUMAYA KHALDI, SALOUA
BEN KHAMSA JAMELEDDINE

DEPARTMENT OF PHYSIOLOGY AND FUNCTIONAL EXPLORATIONS, ABDERRAHMENE MAMI
HOSPITAL, ARIANA

Introduction : Chronic Obstructive Pulmonary Disease (COPD) is characterized by
airflow limitation and hyperinflation, contributing to exercise intolerance and
exacerbation risk. The Inspiratory Capacity to vital Capacity ratio (IC/VC) reflects
ventilatory adaptation and could serve as a non-invasive predictor of exacerbation
risk.

Methods : We conducted a cross-sectional study including 100 stable male COPD
patients. Patients were classified as exacerbators (≥1 exacerbation in the previous
year) and non-exacerbators. Clinical data were collected, including dyspnea
severity (mMRC scale), symptom burden (CAT score), smoking history, and
comorbidities. GOLD 2024 classification (groups A, B, E) was used for patient
stratification. Pulmonary function testing included spirometry with both forced and
slow maneuvers to assess FEV₁, FVC, SVC, and IC. The IC/VC ratio was calculated
at rest.

Results : Mean age was 63.0 ± 8.5 years and mean BMI was 24.3 ± 4.5 kg/m ². The
mean CAT score was 13.2 ± 7.4, and the mean mMRC score was 1.6 ± 0.9. Smoking
exposure averaged 50.1 ± 28.8 pack-years. GOLD group distribution was as follows:
group A (29%), group B (38%), and group E (33%). Exacerbations were reported in
57% of patients.
Spirometry showed a mean FEV₁ of 47.7 ± 18.1%, FVC of 76.6 ± 16.7%, and IC of 64.3
± 21.0%. The mean IC/VC ratio was significantly lower in exacerbators compared to
non-exacerbators (0.62 ± 0.15 vs. 0.69 ± 0.16; p = 0.039). Logistic regression identified
a lower IC/VC ratio as an independent predictor of exacerbations (OR = 0.054; 95%
CI: 0.003–0.98; p = 0.044).

Conclusion : The IC/VC ratio, a simple and non-invasive index, is significantly
associated with exacerbation risk in COPD. It may serve as a surrogate marker of
ventilatory reserve and dynamic hyperinflation and could support better risk
stratification in clinical practice.

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