Evaluation of psychological and physiological predictors of fatigue in patients with COPD

Abstract

Abstract Background Fatigue in COPD impairs functional status; however there are few studies examining mechanistic pathways of this symptom. The aims of this study are to compare fatigue between COPD patients and healthy age-matched subjects, and to identify predictors of fatigue in COPD. Methods Seventy four COPD patients, mean age 69.9 (49-87) yrs, mean (SD) % predicted FEV1 46.5 (20.0) % and FEV1/FVC ratio 0.45 (0.13) and 35 healthy subjects, mean age 67.1 (50-84) yrs completed the Multidimensional Fatigue Inventory (MFI 20). Patients' assessment included Depression (HADS), lung function, BMI, muscle strength, incremental shuttle walk test (ISWT), exercise oxygen saturation (SpO2), Borg breathlessness (CR-10) and exertion (RPE). Serum level of Interleukin 6 (IL-6) was recorded. Differences in MFI 20 between groups were examined and predictors of fatigue identified using logistic regression. Results Significant differences (p 2 (R2 = .62); of Physical Fatigue: depression, % predicted FEV1, ISWT and age (R2 = .57); Reduced Activity: % predicted FEV1, BMI and depression (R2 = .36); Reduced Motivation: RPE, depression and end SpO2 (R2 = .37) and Mental Fatigue: depression and end SpO2 (R2 = .38). Conclusion All dimensions of fatigue were higher in COPD than healthy aged subjects. Predictive factors differ according to the dimension of fatigue under investigation. COPD-RF is a multi component symptom requiring further consideration.