COPD assessment test and FEV₁: do they predict oxygen uptake in COPD?

Area of Science:

• Pulmonology
• Cardiorespiratory Physiology
• Clinical Exercise Testing

Background:

• Chronic Obstructive Pulmonary Disease (COPD) presents complex local and systemic effects requiring multifactorial evaluation.
• Assessing disease severity and individual impact necessitates understanding limitations in maximal aerobic capacity.
• Peak oxygen uptake (VO₂peak) is a key indicator of aerobic capacity, but its direct measurement can be challenging in clinical practice.

Purpose of the Study:

• To investigate the correlation between readily available clinical variables and maximal aerobic capacity in COPD patients.
• To develop predictive models for estimating peak oxygen uptake (VO₂peak) using accessible clinical data.
• To identify simple tools for assessing aerobic fitness in individuals with COPD.

Main Methods:

• A cohort of COPD patients underwent clinical evaluation and cardiopulmonary exercise testing.
• Pearson or Spearman correlation analyses were used to assess the relationship between VO₂peak, FEV₁ (% pred.), and COPD Assessment Test scores (CATs).
• Simple and multiple linear regression models were employed to estimate VO₂peak from clinical variables.

Main Results:

• VO₂peak demonstrated a strong positive correlation with FEV₁ (% pred.) (r=0.70) and a moderate negative correlation with CATs (r=-0.54).
• A regression model using FEV₁ explained 50% of the variance in VO₂peak, with an error of 2.231 mL⋅kg^-1⋅min^-1.
• A combined model using both CATs and FEV₁ explained 55% of the variance, reducing the error to 2.156 mL⋅kg^-1⋅min^-1.

Conclusions:

• Maximal aerobic capacity in COPD patients is significantly correlated with widely used clinical variables like CATs and FEV₁.
• FEV₁ and CAT scores serve as valuable predictors for estimating VO₂peak in COPD.
• These findings support the use of accessible clinical data for non-invasive assessment of aerobic capacity in COPD management.