Prediction of physical functioning and general health status trajectories on mortality among persons with cognitive impairment

Background The concern posed by the confluence of aging and cognitive impairment is growing in importance as the U.S. population rapidly ages. As such, we sought to examine the predictive power of physical functioning (PF) and general health status (GHS) trajectories on mortality outcomes among persons with cognitive impairment (PCIs). Methods We used group-based trajectory models to identify latent group memberships for PF trajectories in 1,641 PCIs and GHS trajectories in 2,021 PCIs from the National Health and Aging Trends Survey (2011-2018) and applied logistic regressions to predict mortality using these memberships controlling for individual characteristics. Results We identified six trajectory groups for PF and four groups for GHS. Trajectory group memberships for both outcomes significantly predicted mortality. For PF, group memberships largely captured the average levels over time, and worse trajectories (i.e., lower baselines and faster declines) were associated with higher odds of death. The highest mortality risk was associated with the group experiencing a sharp decline early in its PF trajectory, although its average level across time was not the lowest. For GHS, we observed two groups with comparable average levels across time, but the one with a convex-shape trajectory had much higher mortality risks compared to the one with a concave-shape trajectory. Conclusions Our findings highlighted that health trajectories predicted mortality among PCIs, not only because of general levels but also because of the shapes of declines. Close monitoring health deterioration of PCIs is crucial to understand the health burden of this population and to make subsequent actions.