Validation study of the Japanese version of the brief fatigue inventory.

Fatigue has been recognized as one of the most distressing symptoms in cancer patients. Concise assessment is essential to managing this symptom. To that end, the Brief Fatigue Inventory (BFI), a 9-item questionnaire, was designed to assess fatigue in cancer patients. The purpose of this study was to examine the validity and reliability of the Japanese version of this scale (BFI-J), when compared with previously validated fatigue instruments. We randomly selected 252 cancer patients and presented them with the BFI-J, along with the Cancer Fatigue Scale; Profile of Mood States fatigue, vigor, and depression subscales; and European Organization for Research and Treatment of Cancer QLQ-C30. Specifically, the reliability and construct, criterion, convergent, and discriminant validity of each instrument were evaluated. Additionally, fatigue severity classification was explored using the BFI-J. The results indicated that the BFI-J is a brief, valid, and feasible measure of fatigue for use with Japanese cancer patients.