The multidimensional fatigue inventory (MFI-20): psychometrical testing in a Norwegian sample of inflammatory bowel disease (IBD) patients.

OBJECTIVES

To evaluate the psychometric properties of the Norwegian version of the multidimensional fatigue inventory (MFI-20) in patients with inflammatory bowel disease.

METHODS

Participants were recruited from nine hospitals in the southeastern and western parts of Norway. Clinical and sociodemographic data were collected, and participants completed the MFI-20, as well as the Fatigue Questionnaire (FQ). In addition to a confirmatory factor analysis, validity, reliability, test-retest and responsiveness were evaluated.

RESULTS

In total, 410 patients were included. The Norwegian MFI-20 had an acceptable model fit when compared to the original five-dimensional structure. A positive correlation was observed between the dimensions of MFI-20 and the FQ. MFI-20 scores increased according to subjective disease activity, but no differences were observed when using a calprotectin cut-off < or > =250 µg/g mg/kg. All MFI-20 dimensions except 'reduced motivation' in both ulcerative colitis (UC) and Crohn's disease (CD) patients had alpha Cronbach alpha values ≥70, and test-retest reliability revealed good to excellent values. Merely one dimension (Reduced activity) in UC patients reporting improvement did not reach the threshold for acceptable responsiveness according to Guyatt statistics.

CONCLUSIONS

The Norwegian version of MFI-20 is valid, reliable and responsive. The instrument can safely be used in studies using fatigue as an endpoint.