Elucidating clinical context of lymphopenia by nonlinear modelling

A nonlinear approach for detecting relative lymphopenia is suggested by using a health data record based on simple clinical parameters. Two classification methods, neural networks and decision trees, were applied to detect whether a patient has a positive or a negative lymphopenia outcome. Due to a large dimension of input space, a feature selection method was used in the pre-processing stage. All tested models were validated on the same out-of-sample dataset, and a 10-fold cross-validation procedure for testing generalization ability of the models was conducted. The models were compared according to their classification accuracy in the sense of the average hit rate, specificity and sensitivity. The results show that (1) the best neural network model slightly outperforms the decision tree model, (2) the reduced model provides even higher accuracy than the models with all available data, and (3) both methods similarly rank five important predictors of lymphopenia. The paper discusses the relevance of extracted features, and suggests some guidelines for further research.