Relationship between intrinsic capacity, physical resilience and frailty among older adults patients during stroke recovery: a cross-lagged panel study

BACKGROUND: The existing designs are difficult to reveal the causal temporal relationship and dynamic interaction mechanism among intrinsic capacity(IC), physical resilience(PR), and frailty. OBJECTIVE: This study aims to investigate the longitudinal relationships between IC, PR, and frailty in older adults stroke patients during the rehabilitation phase, and to reveal their potential mediating roles. METHODS: From November 2024 to November 2025, this study employed convenience sampling to select stroke patients admitted to the neurology departments of four Grade A tertiary general hospitals in Anhui Province as research subjects. The IC questionnaire, The Physical Resilience Instrument for Older Adults (PRIFOR), and The FRAIL Scale were used as measurement tools, with observations conducted at three time points: discharge (T1),3 months post-discharge (T2), and 6 months post-discharge (T3). The cross-lag model was used to analyze the causal relationships among IC, PR, and frailty in older adults stroke patients during stroke recovery. RESULTS: the FRAIL scores were negatively correlated with PR scores(r = -0.1,00 ~ -0.628) and IC scores(r = -0.136 ~ -0.427), while PR scores were positively correlated with IC scores(r = 0.146 ~ 0.644).Cross-lagged analysis showed (Fig. 1) that IC scores and FRAIL scores had bidirectional predictive effects (β = -0.055 to-0.298, both P < 0.05).Longitudinal mediating effect analysis showed that indirect effect of T2 PR scores between T1 IC scores and T3 FRAIL scores was -0.078 (95%CI = -0.168 ~ -0.074), the direct effect was -0.246 (95%CI = -0.481 ~ -0.252), the total effect was -0.324 (95% CI = -0.583 ~ -0.374), and the mediating effect accounted for 24.07%. CONCLUSIONS: The lower the level of IC, the higher the degree of frailty in the older adults patients with post-stroke recovery, and the PR plays a mediating role between the two.