Timed Up and Go (TUG) Reference Values and Predictive Cutoffs for Fall Risk and Disability in Singaporean Community-Dwelling Adults: Yishun Cross-Sectional Study and Singapore Longitudinal Aging Study

Abstract

Objectives: The "timed up and go" (TUG) test is a simple and widely used test of overall functional mobility. There is a paucity of TUG normative data among Asian individuals who differ in habitual gait speed and fall risk from Western population. The objectives of this study were to determine TUG reference values and optimum cutoffs predicting prevalent and incident disability for community-dwelling adults.

Design: One cross-sectional (Study 1-Yishun Study) and one longitudinal (Study 2-Singapore Longitudinal Aging Study) study in Singapore.

Setting and participants: Study 1 comprised 538 nondisabled, community-dwelling adults aged between 21 and 90 years. Study 2 comprised 1356 community-dwelling older adults aged ≥55 years followed for 3 years.

Methods: Study 1 collected TUG reference values and assessed physiological fall risk (PFR) using the Physiological Profile Assessment (PPA). Study 2 assessed association of TUG with disability with the Barthel Index and the Lawton scale at baseline and follow-up.

Results: From Study 1, mean TUG time for individuals aged 60 to 74 years was 9.80 seconds, shorter than values reported for Westerners of 12.30 seconds. It was significantly associated with high PFR [odds ratio (OR) 1.14, 95% confidence interval (CI) 1.03-1.27], 74.0% agreement, Cohen's kappa = 0.314 (95% CI 0.238-0.390); area under the curve = 0.85 (95% CI 0.80-0.90). A TUG cutoff of 10.2 seconds discriminated high PFR from low PFR with 84.4% sensitivity and 72.6% specificity. In Study 2, the threshold for observing significantly increased risk of disability was ≥9.45 seconds for prevalent disability (OR 2.98, 95% CI 1.41-6.78), functional decline (OR 2.68, 95% CI 1.33-5.80), and incidental disability (OR 2.25, 95% CI 1.08-4.97).

Conclusions and implications: TUG reference values and cutoff predicting disability for community-dwelling older adults in Singapore are consistent with Asian data and lower than for Western individuals. TUG could be used to guide development and evaluation of risk screening of adverse health outcomes across the life span in Singapore.

Keywords: Disability; physiological falls risk; reference values; threshold values; timed up and go.