The impacts of multimorbidity trajectories and patterns on functional limitations over time in middle-aged and older adults

BACKGROUND: Although multimorbidity is a risk factor for functional limitations, few studies have simultaneously examined the impacts of multimorbidity trajectories and patterns on long-term functional limitations change. We aim to identify multimorbidity trajectories and patterns and explore their relationships with functional limitations in middle-aged and older adults. METHODS: This study included 6302 participants aged ≥50 from the English Longitudinal Study of Ageing survey 2008-2021. Group-based trajectory model was conducted to identify multimorbidity trajectories from 22 chronic conditions (2008-2014). Exploratory factor analysis was employed to assess multimorbidity pattern using data collected in 2014. The impacts of multimorbidity trajectories and patterns on the change in functional limitations across the subsequent 7 years (2014-2021) were examined through generalized estimating equation models. RESULTS: This study identified four multimorbidity trajectories: low-maintaining, new-increasing, moderate-increasing, and high-maintaining trajectory and four multimorbidity patterns: multi-system, cardiovascular, vision impairment, and metabolic-skeletal patterns. Across all multimorbidity trajectories and patterns, functional limitations showed sustained increases over time, with levels consistently higher than reference groups (all P < 0.001). There were significant interactions of multimorbidity trajectories and patterns with time, particularly for high-maintaining trajectory (T6:β = -0.218, P = 0.007; T7:β = -0.271, P = 0.004), multi-system pattern (T6:β = -0.323, P = 0.001; T7:β = -0.593, P < 0.001), and metabolic-skeletal pattern (T6:β = -0.313, P < 0.001; T7:β = -0.481, P < 0.001), indicating the high-maintaining multimorbidity trajectory, multi-system and metabolic skeletal patterns accelerated the progression of functional limitations. CONCLUSIONS: Implement targeted preventive interventions and personalized health management strategies for high-risk multimorbidity patients to delay disability onset.