Impact of age on functional recovery following hospital-based rehabilitation in older adults

With a rapidly aging population, accurately predicting rehabilitation outcomes in older adults is increasingly important. As the impact of age on recovery trajectories in geriatric rehabilitation remains unclear, we conducted a retrospective observational study to evaluate the effect of older age on improvements in rehabilitation functional outcomes. We included 158 patients (median age: 84 years; IQR: 77.0-88.0) admitted in 2024 to a geriatric rehabilitation unit. Functional status was assessed at admission and discharge using the Modified Barthel Index (autonomy), Hendrich II Fall Risk Model (fall risk), and Tinetti Scale (balance and gait). Patients were stratified into age tertiles and compared using the Kruskal-Wallis and Mann-Whitney U tests. Multivariable linear regression models evaluated the independent associations of age, sex, and frailty index with functional outcomes. Comparisons of changes in functional outcomes between the youngest (T1) and oldest (T3) age tertiles were performed using the Mann-Whitney U test. Older age was associated with worse baseline functional status, reflected by lower Barthel and Tinetti scores and higher Hendrich II scores. However, in multivariable models, frailty index-but not chronological age-was the strongest independent predictor of all functional outcomes, including Barthel (β = -89.9, p < 0.001), Tinetti (β = -39.9, p < 0.001), and Hendrich II (β = 6.8, p < 0.001). Both younger and older patients achieved significant functional gains, particularly in mobility, whereas improvements in autonomy and fall risk were more limited among the oldest individuals. In conclusion, chronological age was associated with poorer baseline performance but did not impair motor recovery. Frailty, rather than age itself, emerged as the key determinant of rehabilitation outcomes. These findings underscore the importance of integrating standardized frailty assessments to guide rehabilitation strategies and promote equitable access to multidisciplinary rehabilitation for older adults.