Predictive validity of the functional independence and difficulty scale in community-dwelling Japanese older adults

[Purpose] The newly developed Functional Independence and Difficulty Scale is a tool for assessing the performance of basic activities of daily living in terms of both independence and difficulty. The aim of this study was to examine the predictive validity of the scale for decline of instrumental activities of daily living ability and multiple falls during a 24-month follow-up period. [Subjects and Methods] One-hundred forty older adults (median age 74.0, 60% women) completed baseline data collection and a follow-up postal survey. At baseline, background variables, the Functional Independence and Difficulty Scale, and instrumental activities of daily living ability assessed by the five sub-items of Tokyo Metropolitan Institute of Gerontology Index of Competence were recorded. At follow-up, data on instrumental activities of daily living ability and falls in the previous 12 months were obtained. [Results] Of the 140 participants, 15 (10.7%) declined in instrumental activities of daily living ability and 14 (10.0%) experienced multiple falls. The Functional Independence and Difficulty Scale at baseline independently predicted decline of instrumental activities of daily living ability and multiple falls. [Conclusion] The Functional Independence and Difficulty Scale predicts subsequent decline of instrumental activities of daily living ability and multiple falls.