Purpose: Cancer-related fatigue (CRF) is one of the most common symptoms experienced by cancer patients (CPs). The Brief Fatigue Inventory (BFI) is a reliable instrument to assess CRF in CPs. The aim of this study was to evaluate the psychometric properties of the Italian version of the BFI (BFI-I).
Methods: The BFI-I was developed by using the forward-backward translation approach. The psychometric properties of the BFI-I were assessed in terms of acceptability, internal consistency, and validity. Outpatient CPs filled in BFI-I along with the Medical Outcome Study Quality of Life Short Form 36 (SF36). Demographic and health data were collected.
Results: The BFI-I had an overall Cronbach alpha for the nine items of 0.94. The inter-item mean correlation was 0.64, and coefficients ranged from 0.47 to 0.81 for the nine items. The results of the factor analysis suggested a 1-factor solution explaining 68 % of the variance, supporting the hypothesis of unidimensionality of the BFI-I. The BFI-I score was compared to SF36 subscales score to evaluate concurrent validity. An expected inverse correlation between the BFI-I and the vitality subscale of the SF36 was observed (r = -0.67, 95 % confidence interval -0.73 to -0.59). The correlation with the other subscales of the SF36 ranged between -0.56 and -0.13. Discriminant validity analysis showed the BFI-I mean score significantly increased with increasing Eastern Cooperative Oncology Group values (p < 0.001).
Conclusions: BFI-I is a clinical instrument with satisfactory psychometric properties to assess CRF in Italian CPs.