Value of cardiopulmonary exercise testing in the assessment of symptoms and quality of life in Asian patients with chronic obstructive pulmonary disease

Bora Lee; Yeon-Mok Oh; Sei Won Lee; Sang-Do Lee; Jae Seung Lee

doi:10.21037/jtd-23-185

Value of cardiopulmonary exercise testing in the assessment of symptoms and quality of life in Asian patients with chronic obstructive pulmonary disease

J Thorac Dis. 2023 Jul 31;15(7):3662-3672. doi: 10.21037/jtd-23-185. Epub 2023 Jul 18.

Authors

Bora Lee¹, Yeon-Mok Oh¹, Sei Won Lee¹, Sang-Do Lee¹, Jae Seung Lee¹

Affiliation

¹ Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Abstract

Background: The natural course of chronic obstructive pulmonary disease (COPD) is characterized by symptom exacerbation and quality-of-life reduction. Therefore, symptoms should be properly assessed. Some studies have demonstrated a weak correlation between cardiopulmonary exercise testing (CPET) parameters and symptoms in patients with COPD; however, data on Asian patients are lacking. We investigated the value of CPET parameters in assessing symptoms and quality of life in Asian patients with COPD.

Methods: Of 681 patients who underwent CPET at Asan Medical Center between January 2020 and June 2022, we analyzed 195 patients with COPD in this retrospective study. A cycle ergometer was used for the incremental protocol. The modified Medical Research Council (mMRC) dyspnea scale and COPD Assessment Test (CAT) were administered to assess the patients' symptoms.

Results: The mMRC grade was related to maximal oxygen uptake (VO₂ max, L/min) (Spearman's correlation coefficient ρ=-0.295, P<0.001) and physiological dead space/tidal volume ratio at peak exercise (V_D/V_T peak) (ρ=0.256, P<0.001). The CAT score was significantly correlated with VO₂ max (L/min) (Spearman's correlation coefficient ρ=-0.297, P<0.001) and V_D/V_T peak (ρ=0.271, P<0.001), but had no correlation with breathing reserve (ρ=-0.122, P=0.089). The optimal cut-off values of VO₂ max and V_D/V_T peak for predicting the onset of clinically significant dyspnea were 1.099 L/min and 0.295, respectively.

Conclusions: VO₂ max and V_D/V_T peak comprehensively reflect the symptoms and health-related quality of life of patients with COPD.

Keywords: COPD Assessment Test (CAT); Cardiopulmonary exercise testing (CPET); chronic obstructive pulmonary disease (COPD); dyspnea; modified Medical Research Council (mMRC); quality of life.