Mapping the Final Journey: End-Of-Life Frailty Trajectories and Cause of Death

Background: Frailty changes associated with aging have been well-documented in existing research. However, there is limited evidence on how frailty progresses during the end-of-life stage. We aimed to explore trajectories of frailty in the last year of life and explore how the distribution of these trajectories differs according to the conditions leading to death. Methods: Based on national death registries linkage data in the UK Biobank, 37,465 decedents were included in the analytic sample. Monthly frailty scores were obtained for 1 year prior to death using the Hospital Frailty Risk Score (HFRS; a cumulative deficit measure of frailty). Latent class trajectory models were used to estimate trajectories of frailty. We further analyzed the distribution of these frailty trajectories across different conditions leading to death. Multinomial logistic regression models were applied to examine the associations between predictors and frailty trajectories. Results: Among 37,465 decedents, 2895 (7.7%) died from neurodegenerative diseases. Three distinct frailty trajectories were identified among these decedents: rapidly progressive frailty (6.9%), moderate progression of frailty (21.1%), and advanced and stable frailty (72.0%). These patterns differed significantly from those observed in decedents with other causes of death, who exhibited persistently low frailty (24.7%), intermediate and progressive frailty (46.5%), and advanced and progressive frailty (28.8%). Compared to cancer decedents, individuals with neurodegenerative diseases had higher baseline frailty and a dominant trajectory of advanced and stable frailty. Older age, lower education, and greater chronic disease burden were associated with the advanced and progressive frailty trajectory. Conclusions: Frailty trajectories at the end of life varied by cause of death, with neurodegenerative disease decedents exhibiting more severe frailty. These findings underscored the need for early identification of frailty and tailored end-of-life care strategies, particularly for individuals with neurodegenerative diseases who often experienced prolonged and severe frailty.