THE INFLAMMATORY BOWEL DISEASE-FATIGUE PATIENT SELF-ASSESSMENT SCALE: TRANSLATION, CROSS-CULTURAL ADAPTATION AND PSYCHOMETRIC PROPERTIES OF THE BRAZILIAN VERSION (IBD-F BRAZIL).

Background: Fatigue is a common symptom in patients with inflammatory bowel diseases (IBD). A translated and culturally adapted, instrument with robust psychometric for measuring fatigue in Brazilian patients with IBD is needed.
Objective: To translate and cross-culturally adapt the inflammatory Bowel Disease Fatigue Scale (IBD-F) into Brazilian-Portuguese and to test its measurement properties in Brazilian patients with IBD.
Methods: Data from 123 patients with IBD were collected. In addition to IBD-F, the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) was used. The measurement properties tested were: internal consistency, reproducibility (reliability and agreement), construct validity, internal and external responsiveness, and ceiling and floor effects.
Results: The Brazilian-Portuguese version of the IBD-F showed excellent internal consistency (Cronbach's alpha of 0.95), excellent reproducibility (ICC=0.97) and a minimal detectable change of 6.0 points. The construct validity was demonstrated with a good correlation between the IBD-F and FACIT-F (r=- 0.46). Effect sizes used for measuring internal responsiveness were moderate among those with Crohn's (0.66) disease and low in patients with ulcerative colitis (0.24). The Brazilian-Portuguese version of the IBD-F presented with high external responsiveness for Crohn's disease (0.84) and with low external responsiveness for ulcerative colitis (0.33). The area under the curve considered for responsiveness was 0.84. Twenty-five percent of floor effects and no ceiling effect were recorded.
Conclusion: The Brazilian-Portuguese version of IBD-F has adequate measurement properties and its use can be recommended in clinical practice and research.