Assessing Health Care Use Trajectories after the Onset of Functional Disability: Application of a Group-Based Trajectory Model

Objectives: While older adults with activity limitations have high levels of health care use, we do not know how this varies over time. We aimed to assess trajectories of Emergency Department (ED) use and hospitalization after the onset of receipt of help with self-care or mobility. Methods: We used the 2011-2017 National Health Aging Trends Study (NHATS) linked to Medicare claims to identify a cohort of older adults who began to receive help with self-care or mobility in the past year. Primary outcome was the quarterly rates of ED use and/or hospitalization over the 24 months following the onset of receiving help. We fit a Group-Based Trajectory Model to identify the trajectories of ED use or hospitalization and assessed the association of characteristics preceding and concurrent to the onset of help with trajectory group membership. Results: Among 1,687 NHATS respondents newly receiving help with self-care/mobility, health care use escalated and then immediately fell. We found distinct trajectories of ED use and hospitalization: delayed rise (13.5%), falling (26.2%), and persistent (60.4%). Trajectory group membership was predicted by clinical, economic, and regional characteristics; and the individuals in each group differed in terms of concurrent new illnesses and degree of disability. Discussion: While activity limitations are a strong predictor of health care use among older adults, trajectories of health care use are heterogeneous. Along with clinical characteristics, potentially modifiable household and regional factors shaped health care trajectories, indicating that addressing these factors could potentially shift health care use patterns.