Developing a battery of physical performance tests to predict functional disability in Japanese older adults: A longitudinal study from the Kasama study

• Published in: Geriatrics & gerontology international 2024-12, Vol.24 (12), p.1343-1349
• Main Authors: Lim, Namhoon, Tsunoda, Kenji, Nagata, Koki, Asano, Yujiro, Seol, Jaehoon, Jindo, Takashi, Tsuji, Taishi, Okura, Tomohiro
• Format: Article
• Language: English
• Subjects: Activities of Daily Living; Aged; Aged, 80 and over; Aging; Disability Evaluation; Disabled Persons; East Asian People; Female; Geriatric Assessment - methods; Hand Strength - physiology; healthy life expectancy; Humans; Japan; Longitudinal Studies; long‐term care; Male; Medical screening; motor function; nursing home; Older people; physical function; Physical Functional Performance; Postural Balance - physiology; Predictive Value of Tests; Proportional Hazards Models; Quality of life
• ISSN: 1444-1586; 1447-0594; 1447-0594
• DOI: 10.1111/ggi.15008

Aim Preventing functional disability benefits the quality of life of older adults and mitigates the economic burden of an aging society. However, the most effective physical performance tests and optimal cut points for identifying older adults at risk of functional disability remain unclear, and Japan lacks physical function‐based assessment tools. We aimed to identify the physical performance tests related to functional disability and to develop a predictive test battery for it. Methods We included 975 older adults (mean 72.8 ± 5.2 years, 55.4% women) in Kasama City, Japan. Functional disability was defined as certification of care level 2 or above based on the long‐term care insurance system. Cox proportional hazards analysis examined the association between physical performance tests and incident functional disability. Results During a mean follow‐up of 8.6 years (maximum 14 years), 236 participants (24.2%) developed functional disability. After adjusting for covariates, higher performances in grip strength, single‐leg balance with eyes open (SLB), timed up‐and‐go (TUG), five‐repetition sit‐to‐stand (5‐STS), and 5‐m habitual walk were significantly associated with a lower risk of functional disability. In a stepwise model, SLB, TUG, and 5‐STS were key predictors of functional disability. Receiver operating characteristic analysis determined optimal cut points of 32.6/32.7 s for SLB, 6.5/6.6 s for TUG, and 7.8/7.9 s for 5‐STS. We developed a predictive battery combining these cut points (area under the curve = 0.78). Conclusions The developed battery of physical performance tests predicts future functional disability and is useful for screening older adults at high risk. Geriatr Gerontol Int 2024; 24: 1343–1349. We developed a battery of physical performance tests to predict functional disability by combining the cut points for single‐leg balance with eyes open, timed up‐and‐go, and five‐repetition sit‐to‐stand. This simple battery of physical performance tests could be useful for screening older adults at higher risk for functional disability.