A two-layer nested heterogeneous ensemble learning predictive method for COVID-19 mortality.

The COVID-19 epidemic has had a great adverse impact on the world, having taken a heavy toll, killing hundreds of thousands of people. In order to help the world better combat COVID-19 and reduce its death toll, this study focuses on the COVID-19 mortality. First, using the multiple stepwise regression analysis method, the factors from eight aspects (economy, society, climate etc.) that may affect the mortality rates of COVID-19 in various countries is examined. In addition, a two-layer nested heterogeneous ensemble learning-based prediction method that combines linear regression (LR), support vector machine (SVM), and extreme learning machine (ELM) is developed to predict the development trends of COVID-19 mortality in various countries. Based on data from 79 countries, the experiment proves that age structure (proportion of the population over 70 years old) and medical resources (number of beds) are the main factors affecting the mortality of COVID-19 in each country. In addition, it is found that the number of nucleic acid tests and climatic factors are correlated with COVID-19 mortality. At the same time, when predicting COVID-19 mortality, the proposed heterogeneous ensemble learning-based prediction method shows better prediction ability than state-of-the-art machine learning methods such as LR, SVM, ELM, random forest (RF), long short-term memory (LSTM) etc.

Adverse drug reaction detection on social media with deep linguistic features.

Adverse reactions caused by drugs are one of the most important public health problems. Social media has encouraged more patients to share their drug use experiences and has become a major source for the detection of professionally unreported adverse drug reactions (ADRs). Since a large number of user posts do not mention any ADR, accurate detection of the presence of ADRs in each user post is necessary before further research can be conducted. Previous feature-based methods focus on extracting more shallow linguistic features that are unable to capture deep and subtle information in the context, ultimately failing to provide satisfactory accuracy. To overcome the limitations of previous studies, this paper proposes a novel method that can extract deep linguistic features and then combine them with shallow linguistic features for ADR detection. We first extract predicate-ADR pairs under the guidance of extended syntactic dependencies and ADR lexicon. Then, we extract semantic and part-of-speech (POS) features for each pair and pool the features of different pairs to generate a holistic representation of deep linguistic features. Finally, we use the collection of deep features and several shallow features to train the predictive models. A series of experiments are performed on data sets collected from DailyStrength and Twitter. Our approach can achieve AUCs of 94.44% and 88.97% on the two data sets, respectively, outperforming other state-of-the-art methods. The results demonstrate the potential benefits of deep linguistic features for ADR detection on social data. This method can be applied to multiple other healthcare and text analysis tasks and can be used to support pharmacovigilance research.

An improved support vector machine-based diabetic readmission prediction.

BACKGROUND AND OBJECTIVE: In healthcare systems, the cost of unplanned readmission accounts for a large proportion of total hospital payment. Hospital-specific readmission rate becomes a critical issue around the world. Quantification and early identification of unplanned readmission risks will improve the quality of care during hospitalization and reduce the occurrence of readmission. In clinical practice, medical workers generally use LACE score method to evaluate patient readmission risks, but this method usually performs poorly. With this in mind, this study presents a novel method combining support vector machine and genetic algorithm to build the risk prediction model, which simultaneously involves feature selection and the processing of imbalanced data. This model aims to provide decision support for clinicians during the discharge management of patients with diabetes. METHOD: The experiments were conducted from a set of 8756 medical records with 50 different features about diabetic readmission. After preprocessing the data, an effective SMOTE-based method was proposed to solve the imbalance data problem. Further, in order to improve prediction performance, a hybrid feature selection mechanism was devised to select the important features. Subsequently, an improved support vector machine-based (SVM-based) method was developed and the genetic algorithm was used to tune the sensitive parameter of the algorithm. Finally, the five-fold cross-validation method was applied to compare the performance of proposed method with other methods (LACE score, logistic regression, naïve bayes, decision tree and feed forward neural networks). RESULTS: Experimental results indicate that the proposed SVM-based method achieves an accuracy of 81.02%, a sensitivity of 82.89%, a specificity of 79.23%, and outperforms other popular algorithms in identifying diabetic patients who may be readmitted. CONCLUSIONS: Our research can improve the performance of clinic decision support systems for diabetic readmission, by which the readmission possibility as well as the waste of medical resources can be reduced.