Factors influencing performances and indicating risk of falls using the true Timed Up and Go test time of patients with hip fracture upon acute hospital discharge

Objective: To examine the influence and risk of falls of individual factors on timed up and go test (TUG) times using standardized instructions in patients with hip fracture upon discharge from an acute orthopaedic hip fracture unit. Methods: Following instructions, the TUG was performed three times with a rollator (standardized aid), as fast as safely possible. Up to a 1-min rest was given after the first and second TUG trial. Multivariable linear regression analysis was used to investigate the factors influencing TUG-times and corresponding logistic analysis was used to investigate factors indicating risk of falls, using a cut-off of 24 s for TUG. Results: A total of 181 patients (122 women), 60 years or older, with a mean (SD) age of 78.1 (9.1) years were studied. The fastest of three TUG trials performed within a mean of 10.0 (5.2) post-surgery days and used in analyses reached a mean of 25.6 (11.0) s. Multivariable regression analysis showed that greater age (B = 0.24; 2.4s more per decade older), a low pre-fracture function level (New Mobility Score <7 points, B = 6.4s more than high level), having a trochanteric fracture (B = 6.2 s, vs. cervical), and the post-surgery day of testing (B = 0.42, 4.2s per 10 days later) were independently associated with using more time for performing the TUG. Correspondingly, the same four factors indicated an increased risk of falls in the logistic analysis. The linear model explained 28% of the variance on TUG, while the accuracy of the logistic model to predict patients having TUG≥24 s was 69%. Conclusion: The age, pre-fracture function, fracture type and post-surgery day of TUG testing were identified as strong factors influencing TUG performances and TUG-times indicating risk of falls in patients with hip fracture. We suggest that these factors be considered when interpreting TUG test results and in further rehabilitation and fall prevention efforts.