Trajectories of disability in the last year of life

Abstract

Background: Despite the importance of functional status to older persons and their families, little is known about the course of disability at the end of life.

Methods: We evaluated data on 383 decedents from a longitudinal study involving 754 community-dwelling older persons. None of the subjects had disability in essential activities of daily living at the beginning of the study, and the level of disability was ascertained during monthly interviews for more than 10 years. Information on the conditions leading to death was obtained from death certificates and comprehensive assessments that were completed at 18-month intervals after the baseline assessment.

Results: In the last year of life, five distinct trajectories were identified, from no disability to the most severe disability: 65 subjects had no disability (17.0%), 76 had catastrophic disability (19.8%), 67 had accelerated disability (17.5%), 91 had progressive disability (23.8%), and 84 had persistently severe disability (21.9%). The most common condition leading to death was frailty (in 107 subjects [27.9%]), followed by organ failure (in 82 subjects [21.4%]), cancer (in 74 subjects [19.3%]), other causes (in 57 subjects [14.9%]), advanced dementia (in 53 subjects [13.8%]), and sudden death (in 10 subjects [2.6%]). When the distribution of the disability trajectories was evaluated according to the conditions leading to death, a predominant trajectory was observed only for subjects who died from advanced dementia (67.9% of these subjects had a trajectory of persistently severe disability) and sudden death (50.0% of these subjects had no disability). For the four other conditions leading to death, no more than 34% of the subjects had any of the disability trajectories. The distribution of disability trajectories was particularly heterogeneous among the subjects with organ failure (from 12.2 to 32.9% of the subjects followed a specific trajectory) and frailty (from 14.0 to 27.1% of the subjects followed a specific trajectory).

Conclusions: In most of the decedents, the course of disability in the last year of life did not follow a predictable pattern based on the condition leading to death.

Figure 1. Trajectories of Disability in the Last Year of Life among 383 Decedents

The severity of disability is indicated by the mean number of activities of daily living (ADLs) in which the subjects had disability. The solid lines indicate the observed trajectories, and the dashed lines indicate the predicted trajectories. The I bars indicate 95% confidence intervals for the observed severity of disability. The probability that the assigned and observed trajectories would be the same was less than 0.70 (range, 0.51 to 0.69) for only 37 of the decedents (9.7%). For all 37 of these decedents, an adjacent trajectory was associated with the next highest probability of assignment (range, 0.21 to 0.49). Nearly two thirds (23) of these 37 decedents had episodes of recovery from a more severe form of disability, whereas approximately 20% (7) had disability in a single activity in the month before death, without any preceding disability.

Figure 2. Distribution of Disability Trajectories in the Last Year of Life, According to Condition Leading to Death among the 383 Decedents

The values within the bars are the percentages of decedents with the disability trajectories.