Validation of World Guideline gait speed and TUG cut-offs for fall risk stratification in ambulatory nursing home residents aged ≥ 80 years: a multicenter cross-sectional diagnostic study

Falls are highly prevalent among nursing home residents, particularly among adults aged ≥ 80 years. The World Guidelines for Falls Prevention and Management recommend gait speed ≤ 0.8 m/s and Timed Up and Go (TUG) > 15 s as risk thresholds; however, their discriminatory validity in ambulatory institutionalized populations remains insufficiently examined. To validate the discriminatory performance and clinical utility of guideline-recommended gait speed (≤ 0.8 m/s) and TUG (> 15 s) thresholds for fall risk stratification among ambulatory nursing home residents aged ≥ 80 years. In this multicenter cross-sectional diagnostic accuracy study, 132 ambulatory nursing home residents aged ≥ 80 years were recruited from four care homes in Shanghai. Gait speed, TUG performance, and 12-month retrospective fall history were assessed by trained staff. Logistic regression models were developed using a 7:3 derivation–validation split. Model performance was evaluated using area under the receiver operating characteristic curve (AUC), calibration statistics, Brier scores, and decision curve analysis (DCA). Forty-eight participants (36.4%) reported at least one fall in the past year. In the gait speed model, slower gait speed was significantly associated with higher fall risk (OR = 0.078), with moderate discrimination in both the derivation (AUC = 0.799) and validation cohorts (AUC = 0.794). The TUG model demonstrated comparable discrimination (AUC = 0.771 and 0.783 in derivation and validation cohorts, respectively), with prolonged TUG time associated with increased fall risk (OR = 1.096). Both models showed good calibration (Brier scores = 0.168–0.195). Decision curve analysis indicated positive net clinical benefit across clinically relevant threshold ranges. World Guideline gait speed and TUG thresholds demonstrated acceptable discriminatory performance among ambulatory nursing home residents aged ≥ 80 years. These simple mobility assessments may support fall risk stratification within this ambulatory institutional subgroup; however, findings should not be generalized to residents with advanced frailty or dependence on assistive devices.