Validity of the Functional Assessment of Chronic Illness Therapy Fatigue Scale (FACIT-F) in individuals with Chronic Obstructive Pulmonary Disease in Brazil

ABSTRACT Fatigue is one of the most prevalent symptoms in individuals with Chronic Obstructive Pulmonary Disease (COPD), but it is poorly evaluated. The Functional Assessment of Chronic Illness Therapy Fatigue Scale (FACIT-F) is one of the main instruments used to measure fatigue. However, this instrument has not yet been validated for the Brazilian population with COPD. This study aimed to investigate the validity of the FACIT-F fatigue scale in individuals with COPD. In a cross-sectional study, the impact of symptoms (COPD Assessment Test - CAT), dyspnea (modified Medical Research Council - MRC scale), functional capacity (six-minute step test - 6MST), exertional fatigue (Borg modified scale at the end of 6MST), and the FACIT-F scale to assess multidimensional fatigue were evaluated. Concurrent validity was assessed by associating the FACIT-F with the CAT, and convergent validity by associating it with the number of steps, perceived exertional fatigue, and dyspnea. Discriminant validity was assessed by comparing fatigue with the dyspnea severity strata. In total, 92 participants were studied (69.9±8.8 years, FEV1: 48.4% of predicted). The FACIT-F presented an average of 30.1±10.9 points, strong concurrent validity with the CAT (r=-0.80), strong convergent validity with dyspnea (r=−0.66), and low with exercise capacity (r=0.40) and fatigue on exertion (r=-0.44). FACIT-F was effective in discriminating groups with different intensities of dyspnea. Conclusion: The FACIT-F is a valid tool for assessing fatigue in the Brazilian population with COPD.