Heterogeneity in postoperative intrinsic capacity trajectories in older adults with hip fractures: a prospective longitudinal study.

OBJECTIVE

To investigate the group heterogeneity in postoperative intrinsic capacity (IC) recovery trajectories among older hip fracture (HF) patients and identify key independently associated factors.

METHODS

We conducted a prospective longitudinal study of 184 older patients following HF surgery at two tertiary hospitals. IC was assessed at 48 h, pre-discharge, 1 month, and 3 months post-surgery. A multi-state Markov model (MSM) was used to quantify transition intensity and probability between IC states, a latent class growth model (LCGM) was employed to identify heterogeneous trajectories of total IC scores, and predictors of trajectory categories were analyzed via multinomial logistic regression.

RESULTS

MSM revealed that patients in the "severe IC impairment" state had a 96.3% probability of remaining in that state throughout the 3-month follow-up. LCGM further identified three distinct recovery trajectories: the Higher-Level Growth Group (21.2%), the Medium-Level Improvement Group (36.9%), and the Lower-Level Stability Group (41.8%). Multivariate analysis indicated that age 60-69 years was significantly associated with increased odds of belonging to the Medium-Level Improvement Group (OR = 18.12, 95% CI: 4.22-77.86) and the Higher-Level Growth Group (OR = 3.33, 95% CI: 1.10-10.09) compared to the Lower-Level Stability Group. Normal plasma albumin was significantly associated with increased odds of belonging to the Medium-Level Improvement Group (OR = 7.07, 95% CI: 1.30-38.51).

CONCLUSION

From a public health perspective, the identification of three distinct recovery trajectories provides an evidence-based framework for population-level risk stratification. The large subgroup (41.8%) with persistent severe impairment represents a high-risk population that may require targeted resource allocation for post-acute and long-term care. These findings support the development of tiered rehabilitation strategies at the health system level, aligning with the goals of healthy aging.