Assessment of the Validity and Internal Consistency of a Performance Evaluation Tool Based on the Japanese Version of the Modified Barthel Index for Elderly People Living at Home

[Purpose] This study aimed to examine the validity and internal consistency of the Japanese version of a performance evaluation tool for activities of daily living (ADL) based on the modified Barthel Index (PET-MBI) among elderly people at home. [Subjects] The subjects were elderly people living at home in Japan. [Methods] A cross-sectional study was performed at five home care facilities for elderly people in Japan. ADL performance was evaluated for 128 participants using the PET-MBI, which included 10 self-care items. We used confirmatory factor analysis to estimate the factorial validity. We assessed data model fitness with the χ(2) statistic, the Goodness of Fit Index (GFI), Adjusted Goodness of Fit Index (AGFI), and Root Mean Square Error of Approximation (RMSEA). Cronbach's alpha coefficient was used to determine the internal consistency. [Results] The mean age of the participants was 79.1±8.9 years. Among the 126 participants included in the analysis, 67 were women (53.2%). The single-factor model demonstrated a fair fit to the data, with the χ(2) statistic = 74.9 (df =35), GFI = 0.88, AGFI = 0.81, and RMSEA = 0.096, and the path coefficients of each item ranged from 0.44 to 0.95. The alpha coefficient of the 10-item scale was 0.93. [Conclusion] The PET-MBI for elderly people at home was well validated.