Uncertainty-Aware Model for Reliable Prediction of Sepsis in the ICU
Pimentel MAF., Mahdi A., Redfern O., Santos MD., Tarassenko L.
© 2019 Creative Commons. Predicting the onset of sepsis from clinical data is challenging, as physiological and laboratory measurements are sampled at different frequencies and missing data are not randomly distributed. Our team ("CRASHers") propose a two-model approach, where the first predicts a probability of sepsis and the second estimates the uncertainty of these predictions. We then optimize a "decision rule" using both the probability and uncertainty to make the final prediction. A set of derived features was used to train a Gradient Boosting Machine (GBM) classification model to predict sepsis (within 6 hours). A second GBM regression model was trained to estimate the uncertainty of those predictions using a different set of derived features. Optimal hyperparameters for both models were determined using Bayesian optimisation with 5-fold cross validation (using 70% records from each training set). The outputs from both models were then combined using logistic regression (using 15% of records available) to re-calibrate the probability of sepsis. Due to an error in setting up the test environment for our entries, we did not obtain a valid score in the hidden test set. The combined model was evaluated on the remaining 15% of records available for training (i.e., our validation set). Our uncertainty-aware approach achieved a Utility score of 0.412 on our validation set.