Relationship between different indices of exercise capacity and clinical measures in patients with chronic obstructive pulmonary disease.
OBJECTIVE
The purpose of this study was to make comparisons between different types of exercise tests used in chronic obstructive pulmonary disease (COPD) to better interpret the results and to select the most suitable testing procedure. Therefore, we evaluated the relationship between exercise capacity and other clinical measures and their relative contributions to exercise capacity in patients with COPD.


METHODS
We studied 36 patients with stable COPD. All patients underwent baseline pulmonary function testing. Dyspnea during activities of daily living was assessed with the Oxygen Cost Diagram (OCD). The Hospital Anxiety and Depression Scale and the St George's Respiratory Questionnaire were used to assess psychologic status and health-related quality of life, respectively. All patients performed the 6-minute walking test, progressive cycle ergometry, and the cycle endurance test.


RESULTS
Each exercise capacity result correlated significantly with pulmonary function, the OCD, and the Activity and Total scores of the St George's Respiratory Questionnaire. Multiple regression analyses revealed that the OCD was an important predictor of exercise capacity, especially for the walking test. Diffusing capacity was also a significant predictor on progressive cycle ergometry. Body mass index was the most significant predictor of the endurance time.


CONCLUSIONS
The 3 different exercise tests had similar characteristics in relation to pulmonary function, dyspnea, and health-related quality of life in patients with COPD. However, some differences were found in the aspects they evaluated.
Oga
Toru
T
Respiratory Division, Kyoto-Katsura Hospital, 17 Yamadahirao, Nishikyo-ku, Kyoto, 615-8256, Japan.
Nishimura
Koichi
K
Tsukino
Mitsuhiro
M
Hajiro
Takashi
T
Ikeda
Akihiko
A
Mishima
Michiaki
M
D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D004417:Dyspnea / Q000503:physiopathology; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011788:Quality of Life; D012044:Regression Analysis; D011795:Surveys and Questionnaires