As the global population ages, understanding the trajectories of disability in older adults is crucial for improving health outcomes and quality of life. This study aimed to identify patterns of disability index trajectories and associated factors influencing these trajectories in older adults.

A total of 3,227 older adults aged 60 years and older were recruited from four waves of the China Health and Retirement Longitudinal Study (CHARLS, 2011–2018). We used group-based trajectory model to jointly estimate trajectories of disability index and attrition probability, while assessing baseline factors associated with the trajectory membership.

Our findings revealed four distinct trajectories of disability index: slightly limited-gradual deterioration (n = 1661, 51.5%), fluctuating change (n = 588, 18.2%), slightly limited-substantial deterioration (n = 397, 12.3%), and stable severely limited (n = 581, 18.0%). Women, unmarried, lower educational level, living in rural areas, no pension, comorbidity, poor self-rated health, a history of falls, short sleep duration, inadequate social activity, weakness, slowness, and poor chair standing were significantly associated with a higher probability of being in poorer disability index trajectories.

This study highlights the heterogeneity of disability index trajectories in older adults and the multifaceted factors that influence them. Our findings underscore the importance of targeting early prevention or intervention based on the determinants of these trajectories to individual needs to maintain or delay the rate of deterioration of disability in older adults.