Intrinsic Capacity Trajectories: Implications for Subsequent Falls and Hospitalizations among Older Adults

Abstract Background Intrinsic capacity (IC) is the composite of an individual's physical and mental capacities. However, the association between IC trajectories and falls and hospitalizations remains uncertain. This study aimed to determine the IC trajectories among older adults, investigating its association with subsequent risk of falls and hospitalizations. Methods This study enrolled 3,902 older adults aged ≥65 from the National Health and Aging Trends Study (NHATS, wave 2015-2019). A bi-factor model was used for repeated measurements of the five IC domains to generate IC scores for four time points (wave 2015-2018). IC trajectories were identified using group-based trajectory modeling (GBTM), and modified Poisson regression was used to analyze the associations between IC trajectories and subsequent fall and hospitalization risk. Results The mean age of the participants was 76.70 years (SD=6.78), and the majority were female (57.3%). Three IC trajectories were identified, including persistently low (17.86%), persistently moderate (33.96%), and persistently high (48.18%). Compared with the persistently low class, the moderate and high classes have significantly lower fall and hospitalization risk. Multivariate-adjusted RRs for fall occurrence were 0.87 (95% CI:0.78-0.98) and 0.74 (95% CI:0.65-0.85), for multiple falls were 0.81 (95% CI:0.68-0.96) and 0.52 (95% CI:0.41-0.66), for hospitalization occurrence were 0.76 (95% CI:0.66-0.87) and 0.48 (95% CI:0.39-0.58), and for multiple hospitalizations were 0.65 (95% CI:0.53-0.80) and 0.37 (95% CI:0.28-0.48), respectively. Conclusions IC trajectories were associated with falls and hospitalizations. Strategies focusing on improving and maintaining IC at a higher level over time could help reduce the subsequent risk of falls and hospitalizations.