Perception of fatigue and quality of life in patients with COPD.
BACKGROUND
Although dyspnea is considered the primary activity-limiting symptom in patients with COPD, other symptoms, such as fatigue, are frequently reported. The purpose of this study was to determine the relationship between fatigue and pulmonary function, exercise tolerance, depression, and quality of life in patients with COPD.


METHODS
Forty-one patients (age = 62+/-8 years; FEV1 = 1.08+/-0.55 L; FEV1 percent predicted = 35.8+/-17%) from two sites participated in the study. Spirometric measures of pulmonary function were carried out in each patient. The Multidimensional Fatigue Inventory was used to measure five subscales of fatigue: general, physical and mental fatigue, reduction in activity, and reduction in motivation. The St. George Respiratory Questionnaire, used to measure quality of life, has three subscale dimensions (symptom, activity, and impact), as well as an overall or total quality of life score. Depression was measured with the Centers of Epidemiological Studies Depression Scale. In 19 patients, exercise tolerance was determined with the 6-min walking distance.


RESULTS
General fatigue correlated with FEV1, percent predicted (r = -0.32, p < 0.05), exercise tolerance (r = -0.55, p < 0.05), depression (r = 0.44, p < 0.01), and overall quality of life (r = 0.75, p < 0.01). Among the dimensions of fatigue, depression correlated with general and mental fatigue only. Physical dimensions of fatigue correlated with an increase in the severity of pulmonary impairment and reduction in exercise tolerance. The cognitive components of fatigue, such as reduction in motivation and mental fatigue, were not found to be highly correlated with physical dimensions of quality of life. All five subscales of fatigue showed relationship to the functional impact dimension and total impairment score in quality of life.


CONCLUSIONS
These data show a relationship between dimensions of fatigue and pulmonary function, exercise tolerance, and quality of life in COPD. Based on these results, fatigue is an important symptom requiring evaluation and management in patients with COPD. These data clarified also the relationship between depression and fatigue in this patient population.
Breslin
E
E
University of California, Davis, Medical Center, Sacramento 95817, USA.
van der Schans
C
C
Breukink
S
S
Meek
P
P
Mercer
K
K
Volz
W
W
Louie
S
S
D017079:Exercise Tolerance; D005221:Fatigue / Q000209:etiology / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000150:complications* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010465:Perception; D011788:Quality of Life; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires