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

Abstract

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 ARD and evaluate associations with post-fracture DAH and 1-year mortality.

METHODS We conducted a cohort study of 16,576 Medicare beneficiaries living with ADRD who experienced hip fracture between 2010-2017. 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 post-fracture 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 pre-fracture DAH trajectory was associated with less favorable post-fracture 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 pre-fracture DAH trajectory.

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