Effect of symptoms on physical performance in COPD.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients experience multiple symptoms including dyspnea, anxiety, depression, and fatigue, which are highly correlated with each other. Together, those symptoms may contribute to impaired physical performance.

OBJECTIVES: The purpose of this study was to examine interrelationships among dyspnea, anxiety, depressive symptoms, and fatigue as contributing factors to physical performance in COPD.

METHODS: This study used baseline data of 282 COPD patients from a longitudinal observational study to explore the relationship between depression, inflammation, and functional status. Data analyses included confirmatory factor analyses and structural equation modeling.

RESULTS: Dyspnea, anxiety and depression had direct effects on fatigue, and both dyspnea and anxiety had direct effects on physical performance. Higher levels of dyspnea were significantly associated with impaired physical performance whereas higher levels of anxiety were significantly associated with enhanced physical performance.

CONCLUSION: Dyspnea was the strongest predictor of impaired physical performance in patients with COPD.