Development of fall prediction models in community-dwelling older adults: comparison of biological and multidomain models for falls and injurious falls

Falls are a leading cause of morbidity and loss of independence in older adults. Existing fall prediction models vary widely in design and performance, and the added value of incorporating nonbiological factors remains unclear. This study aimed to evaluate the predictive performance of the biological, sociodemographic, behavioral, and environmental domains proposed by the World Health Organization (WHO) for discriminating fall risk in community-dwelling older adults. We conducted a cross-sectional analysis using baseline data from the prospective INITIATE cohort of community-dwelling adults aged ≥ 65 years. LASSO regression with 10-fold cross-validation was used to select biological predictors for any fall and injurious fall outcomes, followed by multivariable logistic regression. Sequential models reflecting sociodemographic, behavioral, and environmental domains were constructed to assess incremental discriminative performance. Model performance was assessed using the area under the ROC curve (AUC), with DeLong’s test used for comparisons. Bootstrap validation (1,000 iterations) was used to assess internal validity. A total of 433 participants were included (median age 76 years; 64% female). For any falls (n = 194, 44.8%), the reduced biological model (mobility limitation, balance, visual acuity, fear of falling) achieved an AUC of 0.64 (95% CI 0.58–0.69). For injurious falls (n = 40, 28.4%), the reduced biological model (Timed Up and Go TUG time, grip strength, executive function, global cognition, and pain interference) achieved an AUC of 0.73 (95% CI 0.64–0.82). Adding sociodemographic, behavioral, and environmental variables produced minimal, nonsignificant improvements for both outcomes (any falls: AUC 0.65, p = 0.46; injurious falls: AUC 0.78, p = 0.30). Parsimonious models based primarily on biological measures can provide clinically meaningful discrimination while remaining feasible for community and outpatient use. The distinct risk profiles for any falls and injurious falls highlight the need for outcome-specific screening approaches. Prospective evaluation and external validation are needed prior to clinical implementation.