Using Concept Hierarchies to Improve Calculation of Patient Similarities
D. Girardi, S. Wartner, G. Halmerbauer, M. Ehrenmüller, H. Kosorus, S. Dreiseitl - Using Concept Hierarchies to Improve Calculation of Patient Similarities - Journal of Biomedical Informatics, Vol. 63, No. 1, 2016, pp. 66-73
Objective: We introduce a new distance measure that is better suited than traditional methods at detecting similarities in patient records by re- ferring to a concept hierarchy. Materials and Methods: The new distance measure improves on dis- tance measures for categorical values by taking the path distance between concepts in a hierarchy into account. We evaluate and compare the new measure on a data set of 800 patients. Results: The new measure shows marked improvements over the standard measures, both qualitatively and quantitatively. Using the new measure for clustering patient data reveals structure that is otherwise not visible. Statistical comparisons of distances within patient groups with similar di- agnoses shows that the new measure is signicantly better at detecting these similarities than the standard measures. Conclusion:The new distance measure is an improvement over the cur- rent standard whenever a hierarchical arrangement of categorical values is available.