Anemia as a Mediator: Bridging Frailty Index and Hip Fracture in Chinese elderly Populations

Changqing Li Xiaojiang Zhao Lei Zhang Chao Ma Wenbo Zhang Hong Ding ^*

• Bengbu Medical College, Bengbu, China

Background: Hip fracture is a significant global public health issue. The link and mechanisms between Frailty index (FI) and hip fracture remain unclear. This research examined how anemia mediates the link between FI and hip fracture.The study analyzed data from the 2015 China Health and Retirement Longitudinal Study (CHARLS), which included 6,326 participants aged 60 and above. The mediating role of anemia in the relationship between FI and hip fracture was examined using bootstrap analysis and linear regression models.After controlling for confounding variables, FI is significantly associated with hip fracture (β0 = 4.02 × 10 -3 , P < 0.001) and anemia (β1 = 4.55 × 10 -2 , P < 0.001). Anemia mediates 18.95% of FI's total effect on hip fracture, with an indirect effect size of 7.62 × 10 -4 and a 95% confidence interval(CI) of 1.39 × 10 -4 to 9.32 × 10 -4 . Subgroup analysis indicated that frail and anemic subjects had a significantly higher risk of hip fracture compared to non-frail and non-anemic individuals, with an odds ratio (OR) of 4.61 and a 95%CI of 2.80-7.61. However, no interaction between frailty and anemia was observed regarding hip fracture risk.The findings suggest that FI and anemia were positively associated with hip fracture, and anemia played a mediating role in the association between FI and hip fracture. Intervention based on exercise, nutrition and medical management can combat anemia and reduce FI and may be an effective way to prevent or delay hip fractures.