The longitudinal decrease in exercise tolerance and disease progression in mild-to-moderate COPD

Exercise intolerance serves as a prognostic marker for poor respiratory outcomes in mild-to-moderate COPD. However, the longitudinal change in exercise tolerance and its association with disease progression remains unknown. We aimed to explore the association of longitudinal change in exercise tolerance with disease progression in mild-to-moderate COPD.

This community-based, prospective cohort study was conducted in China from 2019 to 2024. The participants completed baseline questionnaires, spirometry, chest computed tomography, and cardiopulmonary exercise testing (CPET), and underwent annual acute exacerbation assessment and spirometry over 3 years. Participants were categorized by the longitudinal change in peak oxygen uptake from baseline to 3 years into groups with non-declined or declined exercise tolerance.

Overall, 213 participants with mild-to-moderate COPD who completed baseline and 3-year CPET were analyzed, including 131 (61.5%) with exercise tolerance decline. For every 5% longitudinal decrease in exercise tolerance, there was greater progression of air trapping (adjusted difference = 0.18%/year, 95% CI 0.01-0.34, P = 0.033) and a faster decline in postbronchodilator FEV₁ (adjusted difference = -4.2 ml/year, 95% CI -8.3 to -0.1, P = 0.044). Compared with the non-declined exercise tolerance group, the group with exercise tolerance decline demonstrated greater progression of emphysema (adjusted difference = 0.40%/year, 95% CI 0.10-0.69, P = 0.008) and air trapping (adjusted difference = 1.26%/year, 95% CI 0.41-1.84, P = 0.002).

The longitudinal decrease in exercise tolerance over 3 years was associated with accelerated lung function decline and air trapping progression, suggesting it may be a marker associated with disease progression in mild-to-moderate COPD.