Regaining pre-fracture basic mobility status after hip fracture and association with post-discharge mortality and readmission-a nationwide register study in Denmark

Background: early mobilization after hip fracture (HF) is an important predictor of outcome, but knowledge of the consequences of not achieving the pre-fracture basic mobility status in acute hospital recovery is sparse.

Objective: we examined whether the regain of pre-fracture basic mobility status evaluated with the cumulated ambulation score (CAS) at hospital discharge was associated with 30-day post-discharge mortality and readmission.

Design: this is a population-based cohort study.

Measures: using the nationwide Danish Multidisciplinary HF Database from January 2015 through December 2015, 5,147 patients 65 years or older undergoing surgery for a first-time HF were included. The pre-fracture and discharge CAS score (0-6 points with six points indicating an independent basic mobility status) were recorded. CAS was dichotomized as regained or not and entered into adjusted Cox regression overall analysis and stratified by sex, age, body mass index, Charlson comorbidity index, type of fracture, residential status and length of acute hospital stay. Outcome measures were 30-day post-discharge mortality and readmission.

Results: overall mortality and readmission were 8.3% (n = 425) and 17.1% (n = 882), respectively. Mortality was 3.5% (n = 71) among patients who regained their pre-fracture CAS score compared with 11.4% (n = 354) among those who did not. Adjusted hazard ratios for 30-day mortality and readmission were 2.76 (95% confidence interval [CI] = 2.01-3.78) and 1.26 (95% CI = 1.07, 1.48), respectively, for patients who did not regain their pre-fracture CAS compared with those who did.

Conclusions: we found that the loss of pre-fracture basic mobility level upon acute hospital discharge was associated with increased 30-day post-discharge mortality and readmission after a first time HF.