Dynamic frailty trajectories, multidimensional resilience, and risk of incident hip fracture: A prospective cohort study with competing risk analysis

• Rising frailty trajectories are strong predictors of incident hip fractures. • Incident hip fracture risk shows a plateau in accelerated frailty trajectories. • High resilience is independently associated with a 56% lower hip fracture risk. • This protective association is robust, particularly in adults under 75 years of age. Hip fractures represent a major public health challenge in aging populations. While frailty is a recognized risk factor, evidence regarding the protective association of multidimensional resilience trajectories remains insufficient. Data from five waves of the China Health and Retirement Longitudinal Study (CHARLS, 2011–2020), including 7,105 participants aged ≥ 60. A multidimensional resilience index (MDRI) was quantified via the system-level residual method. Latent Class Growth Modelling (LCGM) identified dynamic trajectories of frailty and resilience. Fine-Gray models evaluated their associations with incident hip fracture risk, treating death as a competing risk. Three frailty trajectories were identified: Low-Stable (53.4%), Moderate-Rising (21.2%), and High-Rising (25.4%). Compared to Low-Stable, both Moderate-Rising ( SHR = 1.48; 95% CI: 1.11–1.97; P = 0.007) and High-Rising ( SHR = 1.50; 95% CI: 1.13–1.99; P = 0.005) groups increased fracture risks, suggesting a risk plateau during frailty acceleration. High-level MDRI trajectories showed a potent independent protective association ( SHR = 0.44; 95% CI: 0.30–0.64; P < 0.001). This protection was robust across sex and socioeconomic subgroups ( P interaction > 0.05).While consistent across age groups ( P interaction = 0.177), the association was more pronounced in individuals aged < 75 years ( SHR = 0.42; 95% CI: 0.27–0.67). Rising frailty trajectories, rather than baseline status alone, are strong predictors of incident hip fractures. MDRI confers a robust and independent protective association, reducing fracture risk by 56%. Fracture prevention strategies should move beyond static risk assessments towards monitoring the dynamic acceleration of frailty and actively promoting resilience-building assets in older populations.