Associations of Days Spent at Home Before Hip Fracture With Postfracture Days at Home and 1-Year Mortality Among Medicare Beneficiaries Living With Alzheimer's Disease or Related Dementias.

Background: Hip fracture is a disabling event experienced disproportionately by older adults with Alzheimer's disease or related dementias (ADRD). Claims information recorded prior to a hip fracture could provide valuable insights into recovery potential for these patients. Thus, our objective was to identify distinct trajectories of claims-based days at home (DAH) before a hip fracture among older adults with ADRD and evaluate associations with postfracture DAH and 1-year mortality.

Methods: We conducted a cohort study of 16 576 Medicare beneficiaries living with ADRD who experienced hip fracture between 2010 and 2017. Growth mixture modeling was used to estimate trajectories of DAH assessed from 180 days prior to fracture until index fracture admission, and their joint associations with postfracture DAH trajectories and 1-year mortality.

Results: Before a hip fracture, a model with 3 distinct latent DAH trajectories was the best fit. Trajectories were characterized based on their temporal patterns as Consistently High (n = 14 980, 90.3%), Low but Increasing (n = 809, 5.3%), or Low and Decreasing (n = 787, 4.7%). Membership in the Low and Decreasing prefracture DAH trajectory was associated with less favorable postfracture DAH trajectories, and a 65% higher 1-year mortality rate (hazard ratio 1.65, 95% confidence interval 1.45-1.87) as compared to those in the Consistently High trajectory. Similar albeit weaker associations with these outcomes were observed for hip fracture survivors in the Low but Improving prefracture DAH trajectory.

Conclusions: Distinct prefracture DAH trajectories among hip fracture survivors with ADRD are strongly linked to postfracture DAH and 1-year mortality, which could guide development of tailored interventions.