Admission clinical and functional assessments for predicting inpatient fall risk using machine learning models.

Objectives: Falls are a major patient safety concern in inpatient care. This study aimed to develop machine learning models using multidimensional clinical factors to improve early identification of high-risk patients. Methods: A retrospective dataset of 483,174 adult inpatients was analyzed. Logistic Regression, Support Vector Machine, Random Forest, Extreme Gradient Boosting, and Multi-Layer Perceptron were applied. Models were trained with and without SMOTENC and evaluated using five-fold cross-validation, with emphasis on AUC-ROC, recall, and F1-score. Results: Key predictors included fall history, medication use, dizziness, sensory impairment, and reduced functional status. Without SMOTENC, models achieved moderate AUC-ROC values ranging from 0.62 to 0.72, but exhibited extremely low recall and F1-scores for fall events. After applying SMOTENC, AUC-ROC remained stable in the range of 0.67 to 0.70, while recall improved substantially to approximately 50 to 60 percent. Random Forest and XGBoost demonstrated relatively stable AUC-ROC performance, whereas MLP showed limited generalization ability. Conclusions: Machine learning models can capture clinically relevant fall risk factors, with AUC-ROC indicating moderate discrimination. Severe class imbalance substantially limits minority event detection. Although SMOTENC improves recall, it introduces a precision-recall trade-off, underscoring the need to interpret AUC-ROC alongside class-specific metrics in imbalanced clinical datasets.