Frailty transitions and types of death in Chinese older adults: a population-based cohort study

BACKGROUND: Little is known about the adverse effects of frailty transitions. In this study, we aimed to characterize the transitions between frailty states and examine their associations with the type of death among older adults in China, a developing country with a rapidly growing aging population. METHODS: We used data of 11,165 older adults (aged 65-99 years) from the 2002 and 2005 waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Overall, 44 health deficits were used to construct frailty index (FI; range: 0-1), which was then categorized into a three-level variable: nonfrail (FI ≤0.10), prefrail (0.10< FI ≤0.21), and frail (FI >0.21). Outcome was four types of death based on bedridden days and suffering state (assessed in the 2008 wave of CLHLS). RESULTS: During the 3-year period, 3,394 (30.4%) participants had transitioned between different frailty states (nonfrail, prefrail, and frail), one-third transitioned to death, and one-third remained in previous frailty states. Transitions to greater frailty (ie, "worsening") were more common than transitions to lesser frailty (ie, "improvement"). Among four categories of frailty transitions, "worsening" and "remaining frail" had increased risks of painful death, eg, with odds ratios of 1.92 (95% confidence interval [CI] =1.41, 2.62) and 4.75 (95% CI =3.32, 6.80), respectively, for type 4 death (ie, ≥30 bedridden days with suffering before death). CONCLUSION: This large sample of older adults in China supports that frailty is a dynamic process, characterized by frequent types of transitions. Furthermore, those who remained frail had the highest likelihood of experiencing painful death, which raises concerns about the quality of life in frail populations.