Developing and validating a machine learning-based model for predicting in-hospital mortality among ICU-admitted heart failure patients: A study utilizing the MIMIC-III database

Abstract

Background: Although the assessment of in-hospital mortality risk among heart failure patients in the intensive care unit (ICU) is crucial for clinical decision-making, there is currently a lack of comprehensive models accurately predicting their prognosis. Machine learning techniques offer a powerful means to identify potential risk factors and predict outcomes within multivariable clinical data.

Methods: This study, based on the MIMIC-III database, extracted demographic characteristics, vital signs, laboratory test values, and comorbidity information of heart failure patients using structured query language. LASSO regression was employed for feature selection, and various machine learning algorithms were utilized to train models, including logistic regression (LR), random forest (RF), and gradient boosting (GB), among others. An ensemble learning model based on a soft voting mechanism was constructed. Model performance was evaluated using accuracy, recall, precision, F1 score, and AUC values through cross-validation and on an independent test set.

Results: In five-fold cross-validation, the soft voting ensemble learning model demonstrated the best overall performance, with accuracy and AUC values both at 0.86. Additionally, RF and GB models also performed well, with RF achieving an accuracy of 0.79 and an AUC of 0.79 on the independent test set, while the GB model achieved an accuracy of 0.77 and an AUC of 0.79. In contrast, other models such as LR, SVM, and KNN exhibited poorer performance in terms of accuracy and AUC values, indicating the significant advantage of ensemble methods in handling complex clinical prediction tasks.

Conclusion: This study demonstrates the potential of machine learning models, particularly ensemble learning models based on soft voting mechanisms, in predicting in-hospital mortality risk among heart failure patients in the ICU. The overall performance of the ensemble learning model confirms its effectiveness as an adjunct clinical decision-making tool. Future research should further optimize the models and validate them in a broader patient population to enhance their practical utility and accuracy in real clinical settings.

Keywords: Heart failure; in-hospital mortality risk; intensive care unit; machine learning.

Figure 1.

Visualization of the LASSO feature screening process, where (a) represents the relationship curve between the cross-validation score and log(λ); (b) represents the LASSO coefficient profile of the feature; (c) represents the bar chart of the feature coefficient value; (d) represents the 3D visualization of the principal component analysis.

Figure 2.

ROC curve of the model in independent testing.

Figure 3.

Confusion matrices for each model in independent tests.