Psychometric properties of the Polish version of the Multidimensional Fatigue Inventory-20 in cancer patients.

Abstract

Multidimensional questionnaires estimating cancer-related fatigue (CRF) as a symptom cluster or a clinical syndrome primarily have been used and validated in English-speaking populations. However, cultural issues and language peculiarities can affect CRF assessment The main aims of this study were to evaluate the psychometric properties of the Polish version of the Multidimensional Fatigue Inventory-20 (MFI-20) and to deliver to clinicians a multidimensional tool for CRF assessment in Polish-speaking patients with cancer. After forward-backward translation procedures, the Polish version of MFI-20 was administered to 340 cancer patients. The Polish MFI-20 was appraised in terms of acceptability, reliability, and validity. Internal consistency was assessed by calculating Cronbach's alpha coefficients. Structural validity was evaluated with confirmatory factor analysis. The translated MFI-20 was well accepted; 90% of subjects fully completed the questionnaire. The overall Cronbach's alpha coefficient was 0.9, ranging from 0.57 to 0.81. All correlation coefficients among Numeric Rating Scale-fatigue, fatigue-related items from the European Organization for Research and Treatment of Cancer Quality of Life Core-30 questionnaire, and the MFI--20 were statistically significant (P < 0.001). Confirmatory factor analysis demonstrated good structural validity and revealed only three dimensions in the Polish version of the MFI-20-physical and mental fatigue as well as reduced motivation. The Polish version of the MFI-20 is well accepted by patients, reliable, and a valid instrument to assess CRF in Polish cancer patients.