Factors Related to Fatigue and Physical Function in COPD: A Secondary Analysis Using National Survey Data.

Fatigue in chronic obstructive pulmonary disease (COPD) is debilitating and associated with considerable morbidity. The aim of this study is to present a model based on the Theory of Unpleasant Symptoms of physiologic, psychologic, and situational factors with COPD-related fatigue and the relationship with physical functioning. This study used data collected from Wave 2 (2010-2011) of the National Social, Health, and Aging Project (NSHAP). A total of 518 adults with self-reported COPD were included in this study. Path analysis was used for hypothesis testing. Depression was the only psychologic factor found to have a direct relation to both fatigue (β = 0.158, < .001) and physical function (β = -0.131, = .001). Factors related to physical function included fatigue, depression, sleep, loneliness, and pain. Additionally, fatigue was indirectly associated with physical function via depression (β = -0.064, = .012). These findings suggest avenues for future research on predictors of COPD-related fatigue in relation to physical functioning.