Unravelling associations between fatigue and key outcomes in patients with COPD

Fatigue is a prevalent, multi-dimensional and burdensome symptom in chronic obstructive pulmonary disease (COPD), yet it is still underdiagnosed, undertreated and little understood. This study explored associations between fatigue and key outcomes in COPD and which of them could explain fatigue. A cross-sectional study with people with COPD was conducted. Assessments included the modified functional assessment of chronic illness therapy-fatigue subscale (mod-FACIT-FS; lower scores mean worst fatigue), modified Medical Research Council dyspnea scale (mMRC), six-minute walk test (6MWT), COPD assessment test (CAT) and St. George’s Respiratory Questionnaire (SGRQ). Correlations were explored with the Pearson’s (r)/Spearman’s (rs) coefficients. Multiple linear regressions were performed with the stepwise model and the variance inflation factor (VIF) was confirmed. 89 people with COPD (68±9years; 76%male; 50±18FEV1pp) were enrolled. Significant moderate correlations were found between the mod-FACIT-FS and all outcomes (mMRC:rs=-0.53; 6MWT:r=0.50; CAT:r=-0.56; SGRQ:r=-0.63; p<0.01). The linear regression model showed that SGRQ, 6MWT and CAT explained 51% of the variability in the mod-FACIT-FS (p<0.01; VIF