Descriptive evaluation and accuracy of a mobile app to assess fall risk in seniors: Retrospective Case Control Study (Preprint)
BACKGROUND Fall risk assessment is complex. Based on current scientific evidence, a multifactorial approach including the analysis of physical performance, gait parameters and both extrinsic and intrinsic risk factors is highly recommended. Using these determinants, a smartphone-based application was designed to assess the individual risk of falling with a score that combines multiple fall risk factors into one comprehensive metric. OBJECTIVE This study provides a descriptive evaluation of the designed fall risk score as well as an analysis of its discriminative ability based on real-world data. METHODS Anonymous data from 242 seniors was analyzed retrospectively. Data was collected between June 2018 and May 2019 using the fall risk assessment app. First, we provide a descriptive statistical analysis of the underlying dataset. Subsequently, multiple learning models (Logistic Regression, Gaussian Naive Bayes, Gradient Boosting, Support Vector Classification and Random Forest Regression) are trained on the dataset to obtain optimal decision boundaries. The receiver operating curve with its corresponding area under the curve (AUC) and sensitivity were the primary performance metrics utilized to assess the fall risk score’s ability to discriminate fallers from non-fallers. For the sake of completeness, specificity, precision and overall accuracy were provided for each model as well. RESULTS Out of 242 participants with a mean age of 84.6 ± 6.7 years, 139 (57.4%) reported no previous falls (non-faller), while 103 (42.5%) reported a previous fall (faller). The average fall risk was 29.5 ± 12.4 points. The performance metrics for the Logistic Regression Model were AUC = 0.9; Sensitivity = 100%; Specificity = 52%; Accuracy = 73%. The performance metrics for the Gaussian Naive Bayes Model were AUC = 0.9; Sensitivity = 100%; Specificity = 52%; Accuracy = 73%. The performance metrics for the Gradient Boosting Model were AUC = 0.85; Sensitivity = 88%; Specificity = 62%; Accuracy = 73%. The performance metrics for the Support Vector Classification Model are AUC = 0.84; Sensitivity = 88%; Specificity = 67%; Accuracy = 76%. The performance metrics for the Random Forest Model were AUC = 0.84; Sensitivity = 88%; Specificity = 57%; Accuracy = 70%. CONCLUSIONS Descriptive statistics for the dataset were provided as comparison and reference values. The fall risk score exhibited a high discriminative ability to distinguish fallers from non-fallers, irrespective of the learning model evaluated. The models had an average AUC of 0.86, an average sensitivity of 93% and an average specificity of 58%. Average overall accuracy was 73%. Hence, the fall risk app has the potential to support caretakers in easily conducting a valid fall risk assessment. The fall risk score’s prospective accuracy will be further validated in a prospective trial.