A Dynamic Ensemble Learning Algorithm based on K-means for ICU mortality prediction

Abstract This research proposes a Dynamic Ensemble Learning Algorithm based on K-means (DELAK) for intensive care unit (ICU) mortality prediction. Nowadays, the widely applied traditional scoring systems, which predict the mortality risk with some scores reflecting the severity of disease and physiological states of patients in ICU, have shown insufficient predictive performance when faced with large volume of data. Although taking advantage of large volume of data, single machine learning model and ensemble learning methods show an inadequate ability to make personalized predictions for each new patient. Dynamic ensemble selection (DES) methods which are widely studied in pattern recognition field can make personalized prediction but they only select a single classifier instead of ensemble of the results from a pool of classifiers. To overcome the limitations mentioned above, this research proposes an ensemble learning algorithm based on K-means sampling and distance-based dynamic ensemble. K-means sampling helps to achieve the diversity of base classifiers and the distance-based dynamic ensemble is a flexible fusion method which creates a personalized combination of results from base classifiers for each new test sample. To evaluate the performance for mortality prediction of the proposed algorithm, comprehensive experiments are conducted on MIMIC-III dataset. The experimental results show that DELAK achieves outstanding performance in term of AUROC and AUPRC compared with other six fusion strategies, traditional scoring systems, classical ensemble models, i.e. AdaBoost, Bagging and random forest, and dynamic ensemble selection methods. Our proposed DELAK achieves best predictive performance in most mortality prediction tasks.