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

Abstract

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. 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. 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 (VD/VT 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 VD/VT 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 VD/VT peak for predicting the onset of clinically significant dyspnea were 1.099 L/min and 0.295, respectively. VO2 max and VD/VT peak comprehensively reflect the symptoms and health-related quality of life of patients with COPD.