Predictors of functional limitation trajectories after injury in a nationally representative U.S. older adult population.

Purpose: Studies examining postinjury functional status have demonstrated that individuals with severe injuries often do not return to baseline levels of physical functioning. We sought to investigate the impact injuries have on changes in physical functioning across the life course of older adults. The study's objectives were to (1) identify trajectories of long-term functional limitations after injury in the older adult population to better characterize the recovery process and (2) predict which individuals are most at risk for poor functional trajectories after injury.

Methods: A retrospective cohort study was conducted using six waves of data from the Health and Retirement Study, which surveys Americans older than 50 years every two years. A group-based trajectory model was used to identify trajectories of functional limitations in injured participants. Using multivariate regression, we identified significant predictors of each trajectory.

Results: Five distinct trajectories were identified: Trajectory 1--consistently low functional limitations scores (18.9%), Trajectory 2--increase in functional limitations after injury followed by a gradual, incomplete recovery (46.3%), Trajectory 3--increase in functional limitations followed by further decline in functioning (10.5%), Trajectory 4--increase in functional limitations after injury followed by a gradual, complete recovery (13.4%), and Trajectory 5--consistently high functional limitations scores (10.8%). Gender, multiple health conditions, and insurance status predicted trajectory membership.

Conclusions: Functional limitations after injury follow distinct trajectories that can be predicted by baseline individual characteristics.