Trajectories of disability and their relationship with health status and social service use

BACKGROUND/STUDY CONTEXT: This longitudinal study was conducted between 1994 and 2004 in a cohort of southern Taiwan community-living older residents. The study aims to explore the trajectories of disability and how these patterns differed between respondents who survived and those who died during data collection phases; this study also investigated how health status change and social service use predicted the different trajectories of disability.

Disability, chronic disease, depression, and social service usage data were collected over six waves. Clusters of disability were used to define a categorical response variable. Baseline levels and new occurrences of chronic disease and depression and the frequency of social service use during this period were chosen as the predictors of disability trajectories.

Changes in levels of disability during the aging process were identified. Different trajectories clearly reflected heterogeneity within disability clusters and between surviving and nonsurviving respondents. This study highlighted that hypertension and depression were predictors of increased disability among both surviving and nonsurviving respondents, whereas diabetes was only found to be a strong predictor of increased disability for the nonsurviving respondents. In addition, this study found that use of social services such as personal care, homemaker-household, and physical therapy were significantly associated with an increase in disability, whereas use of recreational services seemed to be associated with a decrease in disability.

These findings identify disability to be a highly dynamic process, which can be characterized into different trajectory clusters (e.g., no, mild, and major disability clusters). A greater awareness of these trajectories could be used to better target strategies to prevent and/or manage disabilities in an aging population.