Dynamics of functional aging based on latent-class trajectories of activities of daily living

Purpose: This study sought to identify and characterize major patterns of functional aging based on activities of daily living (ADL). Methods: We followed 754 community-living adults aged 70 years or older monthly for ADLs, instrumental ADLs, hospitalization and restricted activity over 10 years. A generalized growth mixture model was used to identify trajectories of ADL disability across seven 18-month intervals. Cumulative burdens of disability and morbidity from different trajectories were examined using a generalized estimating equation Poisson model. Results: Five distinct trajectories emerged. The predominant trajectory maintained ADL independence, with membership probability being 61.6%. The remaining trajectories either stayed at low (1 or 2 ADLs, 13.6%) or high (3 or 4 ADLs, 7.0%) levels of disability or declined gradually toward low (11.2%) or high (6.5%) disability. The independent trajectory was associated with the lowest burdens of disability and morbidity and a decreasing time trend of restricted activity, whereas the high disability trajectory demonstrated opposite trends. About 31% of the cohort remained in the same trajectory throughout the follow-up period. Conclusions: The course of functional aging is heterogeneous and dynamic. Although most older adults maintain functional autonomy, some may experience persistent disability or progress toward severe disability with substantial morbidity. (c) 2013 Elsevier Inc. All rights reserved.