Terminal Decline in Physical Function in Older Adults

Abstract

Background: It is currently unclear whether (and when) physical function exhibits a terminal decline phase, that is, a substantial acceleration of decline in the very last years before death.

Methods: 702 deceased adults aged 70 years and older from the Yale PEP Study provided 4 133 measurements of physical function (Short Physical Performance Battery, SPPB) up to 20 years before death. In addition, continuous gait and chair rise subtest scores (in seconds) were assessed. Generalized mixed regression models with random change points were used to estimate the onset and the steepness of terminal decline in physical function.

Results: Decline accelerated in the last years of life in all 3 measures of physical function. The onset of terminal decline occurred 1 year before death for the SPPB, and at 2.5 and 2.6 years before death for chair rise and gait speed test scores, respectively. Terminal declines in physical function were 6-8 times steeper than pre-terminal declines. Relative to those whose condition leading to death was frailty, participants who died from dementia and cancer had an up to 6 months earlier and 3 months later onset of terminal decline in SPPB, respectively.

Conclusions: Terminal decline in physical function among older adults is comparable to the more established terminal decline phenomenon in cognition. Our results provide additional evidence of late-life rapid decline in physical function due to impending death.

Keywords: Change points; End of life; Gait speed; Mortality; Motor decline.

Figure 1.

Observed physical performance scores, estimated average trajectories, and estimated trajectory variation. Sample size = 702 participants and 4 133 (SPPB), 3 645 (gait speed test), 3 327 (chair rise test), and 4 ,133 (MMSE) observations, respectively. Lines in spaghetti plots (first column) refer to observed individual trajectories. Population-average trajectories (second column) are based on mean posterior predictions of fixed effects and adjusted for age to death, light gray shading refers to 95% credible interval. Estimated population variation (third column) is based on posterior predictions for a not yet observed older person using both fixed and random effect variance and shows prediction bands of 25% (dark gray), 50%, 75%, and 95% (light gray). CHAIR = chair time score in seconds; GAIT = rapid gait speed in seconds; SPPB = Short Physical Performance Battery; MMSE = Mini-Mental State Examination.