Diagnostic accuracy of the Timed Up and Go and Five Times Sit-to-Stand tests for fall risk screening in community-dwelling older adults in northern Thailand: a retrospective study

Background Falls are a major public health concern among older adults, yet simple and context-specific screening tools remain under-validated in Thai settings. This study aimed to evaluate the discriminative performance of the Timed Up and Go Test (TUG) and the Five Times Sit-to-Stand Test (FTSST) for fall risk screening. Methods A total of 113 community-dwelling older adults in Chiang Rai, Thailand, were assessed using TUG, FTSST, and the Thai Fall Risk Assessment Tool (Thai-FRAT). Receiver operating characteristic (ROC) curves and logistic regression were used to examine diagnostic accuracy and determine optimal age-specific cut-off values. Results The TUG showed good discriminative performance (AUC = 0.827), whereas the FTSST demonstrated more modest discrimination (AUC = 0.705). Each one-second increase in TUG and FTSST times was associated with higher odds of fall risk (TUG: OR = 1.16, 95% CI [1.07–1.27]; FTSST: OR = 1.11, 95% CI [1.02–1.20]). Discriminative performance was higher in adults aged 60–74 years (TUG AUC = 0.871; FTSST AUC = 0.828) than in those aged ≥ 75 years (0.756 and 0.590, respectively). Overall cut-off values were 17.16 seconds for the TUG and 15.46 seconds for the FTSST, with lower thresholds in younger-old adults and higher thresholds in the oldest-old. Conclusion The TUG demonstrated robust discriminative performance for community-based fall risk screening, whereas the FTSST may be more suitable as a complementary tool. Incorporating age-specific cut-off values may enhance interpretation and support early identification and prevention of falls among older adults.