Translation, validation and psychometric properties of the Dutch version of the Inflammatory Bowel Disease-Fatigue (IBD-F) self-assessment scale

BACKGROUND: In patients with inflammatory bowel disease (IBD), a symptom with major impact on health-related quality of life is fatigue. To assess fatigue and conduct research regarding fatigue in IBD patients, a validated disease specific assessment tool is required. The aim of this study was to translate the Inflammatory Bowel Disease Fatigue patient self-assessment scale (IBD-F) into Dutch and to validate this translated scale in a Dutch IBD population.

METHODS: The study comprised three phases. In phase 1, the original IBD-F was translated into Dutch. Phase 2 comprised a pilot-test of the pre-final Dutch IBD-F to assess content validity by applying a semi-structured interview design. In phase 3, construct validity, internal consistency and test-retest reliability were assessed using a cross-sectional design.

RESULTS: Phase 1 resulted in the pre-final version of the Dutch IBD-F. After five semi-structured interviews with IBD patients in phase 2, minor adjustments were made which resulted in the final version of the Dutch IBD-F. Evaluation of this final version in 133 IBD patients showed adequate psychometric properties: good convergent validity with the Multidimensional Fatigue Inventory subscales (Spearman's r 0.57-0.86) and excellent internal consistency (Cronbach's alpha 0.94 for Section I and 0.97 for Section II). Test-retest reliability in 102 patients was shown to be good (Section I ICC 0.85 (95% CI 0.79-0.90) and Section II ICC 0.88 (95% CI 0.83-0.92)).

CONCLUSIONS: The thorough translation process resulted in a comprehensible, valid and reliable version of the Dutch IBD-F. Convergent validity with the MFI-20 appeared to be good. This study found excellent internal consistency and good test-retest reliability.