Timed Up and Go, gait speed, and grip strength: associations and discriminative performance for falls in community-dwelling older adults - results from the KORA-age study

Background Physical performance measures are commonly used in geriatric assessment and have been associated with falls, but their ability to discriminate between older adults with and without falls may be limited. We compared the Timed Up and Go (TUG) test, gait speed, and grip strength within a population-based cohort, considering associations, discriminatory performance, incremental discrimination, and established clinical TUG thresholds. Methods We analyzed data from 1,079 community-dwelling adults aged ≥ 65 years participating in KORA-Age. Fall status was classified for 819 participants based on self-reported falls in the 12 months preceding the 3-year follow-up interview. Associations of baseline TUG, gait speed, and grip strength with reported falls were examined using sequential logistic regression models adjusted for age and sex, additional clinical covariates, and frailty. Discriminatory performance was assessed using the area under the receiver operating characteristic curve (AUC), with DeLong tests used to evaluate incremental discrimination beyond age and sex. We additionally examined combinations of the three performance measures and predefined TUG thresholds. Inverse-probability weighting was used in sensitivity analyses to address selective follow-up. Results Poorer TUG performance remained associated with reported falls after additional adjustment for frailty (OR per 1-s increase 1.095, 95% CI 1.018–1.176), whereas the association with slower gait speed was attenuated after frailty adjustment and grip strength was not associated with falls. The age- and sex-adjusted reference model had an AUC of 0.680; corresponding AUCs after adding TUG, gait speed, or grip strength were 0.700, 0.692, and 0.675, respectively, with no clear evidence of incremental discrimination. Combining all three performance measures did not improve discrimination beyond TUG alone. Higher TUG thresholds identified smaller groups with a higher prevalence of falls and greater specificity but progressively lower sensitivity. Inverse-probability-weighted analyses yielded similar associations. Conclusion TUG remained associated with reported falls after multivariable and additional frailty adjustment, but none of the three physical performance measures showed clear incremental discrimination beyond age and sex. Combining the measures did not improve discrimination, and established TUG thresholds showed limited sensitivity. These findings support distinguishing statistical associations with falls from the ability of physical performance measures to discriminate between older adults with and without falls. Clinical trial number Not applicable.