The longitudinal association between resilience and frailty in older adults with chronic diseases in China: A national longitudinal study.

BACKGROUND: Frailty seriously threatens health outcomes in older adults with chronic diseases. Identifying modifiable protective factors is a public health priority. Existing evidence on resilience is largely cross-sectional, which leaves a gap in understanding its relationship with long-term frailty. OBJECTIVE: This study characterizes trajectories and heterogeneity of resilience and frailty, identifies predictors of trajectory class membership, and explores their longitudinal dynamic association in Chinese older adults with chronic diseases. METHODS: Data from 1278 older adults with chronic diseases were derived from the Chinese Longitudinal Healthy Longevity Survey (2008-2018). Unconditional latent growth curve models (LGCM) examined average trajectories. Growth mixture models (GMM) identified distinct frailty trajectory classes, followed by firth multinomial logistic regression for predictors. A parallel process latent growth curve model (PP-LGCM) estimated co-development and dynamic interrelationships. RESULTS: Resilience showed no significant change over time (Mslope = -0.024, p > 0.05), while frailty significantly increased (Mslope = 0.030, p < 0.001). GMM identified three frailty trajectories: low-frailty slow-growth (83.8%), low-frailty rapid-growth (10.3%), and high-frailty maintenance (5.9%). PP-LGCM showed that resilience intercept was negatively associated with frailty intercept (β = -0.619, p < 0.001) and slope (β = -0.350, p < 0.01), and resilience slope was negatively associated with frailty slope (β = -0.754, p < 0.001). CONCLUSION: Resilience is inversely related to the progression of frailty. Higher baseline resilience may be associated with lower initial frailty and slower worsening. Heterogeneous frailty trajectories highlight high‑risk subgroups for targeted interventions.