journal articles
A FRAILTY-INTRINSIC CAPACITY INDEX TO PREDICT DISABILITY IN COMMUNITY-DWELLING OLDER JAPANESE ADULTS
Rei Otsuka, Yukiko Nishita, Hyuma Makizako, Hyuma Makizako, Chikako Tange, Mana Tateishi, Shu Zhang, Sayaka Kubota, Kanno Fujikawa, Fujiko Ando, Hiroshi Shimokata, Fumihiro Mizokami, Tomoe Ogayu, Mai Kabayama, Kei Kamide, Shosuke Satake, Hidenori Arai
J Aging Res & Lifestyle 2025;14
PURPOSE: We constructed and validated a frailty-intrinsic capacity (FR-IC) index for predicting disability in community-dwelling older Japanese adults.
METHODS: This longitudinal cohort study included 1179 participants aged ≥60 years (mean age: 71.3 ± 7.4 years, 51 % men). A multidisciplinary geriatric team constructed a 35-item FR-IC index (score range: 0: robust to 1: severe frailty, accumulation model) comprising 15 domains incorporating the intrinsic capacity concept (IC-Vision, IC-Hearing, IC-Locomotor capacity, IC-Cognition, IC-Vitality, and IC-Psychological capacity) based on questionnaires widely used in Japan. To test predictive validity, age- and sex-adjusted Cox proportional hazard models estimated hazard ratios (HRs) for incident disability (care need levels ≥1) by FR-IC index quartiles using the cohort study’s existing data.
RESULTS: The mean FR-IC index score (32 items, three missing) was 0.08±0.05 (range: 0.00–0.31). During a mean follow-up of 9.0 ± 2.8 years, 284 (24 %) adults developed a disability. Compared with the lowest quartile, the adjusted HRs for developing an incident disability in the second to fourth quartiles were 2.32 (95 % confidence interval: 1.15–5.33), 3.18 (1.64–7.15), and 4.15 (2.14–9.32), respectively. The area under the curve of the FR-IC index for incident disability was 0.86. Among healthy participants, defined as robust by the baseline phenotypic physical frailty assessment (n = 437), sex- and age-adjusted HRs for incident support care through the second to third tertiles were 1.72 (0.79–4.30) and 2.51(1.17–6.22), respectively (trend P = 0.028).
CONCLUSIONS: The novel FR-IC index can predict future disability among community-dwelling older Japanese adults. Integrating IC into frailty assessments provides a more comprehensive measure of aging.
CITATION:
Rei Otsuka ; Yukiko Nishita ; Hyuma Makizako ; Kaori Kinoshita ; Chikako Tange ; Mana Tateishi ; Shu Zhang ; Sayaka Kubota ; Kanno Fujikawa ; Fujiko Ando ; Hiroshi Shimokata ; Fumihiro Mizokami ; Tomoe Ogayu ; Mai Kabayama ; Kei Kamide ; Shosuke Satake ; Hidenori Arai (2025): A frailty-intrinsic capacity index to predict disability in community-dwelling older Japanese adults. The Journal of Aging and Lifestyle (JARLife). https://doi.org/10.1016/j.jarlif.2025.100042