[Frailty trajectories in people aged 50 years and above in China]

Objective: To identify distinct frailty trajectories in a cohort of nationwide community adults aged 50 years and above, and explore the relationship between frailty trajectories and their socioeconomic characteristics and behavioral factors at baseline survey. Methods: Data were from the three waves of "Global Ageing and Adult Health Research" (SAGE) by World Health Organization in China. The frailty index is generated from 32 items. Group-based trajectory modeling using a censored normal model was conducted to identify the patterns in frailty progression over time. Multinomial logistic regression model was used to examine the effect of socioeconomic status and behavioral factors on the frailty trajectories. Results: A total of 4 303 adults aged 50 years and above with complete data from all three rounds of project were included in the final analysis. Three frailty trajectories were identified: low and stable trajectory (LT) (56.8%), moderately increased trajectory (MT) (34.4%) and highly increased trajectory (HT) (8.8%). The results of the multinomial logistic regression analysis showed that the HT group was more likely to be women (OR=1.88, 95%CI:1.22-2.92) and rural residents (OR=1.87, 95%CI:1.29-2.70) compared with the LT group. In terms of household wealth per capita, there was a clear gradient in ORs, the people with lower household wealth were more likely to be classified in the HT group. Conclusion: This study identified three patterns of progression of frailty trajectories in population aged 50 years and above in China and highlighted that interventions should target those vulnerable populations with rapid progression of frailty.