For a long time, cardiovascular diseases have been the leading cause of death worldwide. Machine learning has found significant usage in the medical field as it can find patterns in data. Classification models can help cardiologists to diagnose heart diseases and minimize misdiagnosis accurately. In this paper, we explored a dataset related to heart disease and compared the accuracy of 43 machine learning classification models. The dataset for this research was downloaded from Kaggle; it contained 1190 observations, 11 features (age, sex, chest pain type, resting blood pressure, serum cholesterol, fasting blood sugar, resting electrocardiogram results, maximum heart rate achieved, exercise induced angina, oldpeak, the slope of the peak exercise ST segment) and a binary target variable (no heart disease or observed cardiovascular disease). For data exploration, preprocessing, training, testing, and predictor importance analysis, we used MATLAB R2004a software and the Classification Learner app included in this software. Before training machine learning classification models, we divided the dataset into a training set (90% of observations) and a test set (10% of observations). To prevent overfitting during the training of classification models, 10-fold cross-validation was used. The result showed that the best accuracy was reached with an optimized ensemble classification model (validation accuracy: 0.9262 and test accuracy: 0.9580). After calculating the permutation importance of each feature, we observed that the most important feature among all 11 features was the slope of the peak exercise ST segment.
This paper compares different optimizable machine learning classification models to predict eight types of anemia from complete blood count (CBC) data. For the research, we used a publicly available Kaggle dataset containing 1281 observations, 14 predictors, and the diagnosis as the categorical target variable with nine categories (eight types of anemia and the healthy category). First, we examined the dataset and observed the histograms of some of the predictors. We compared the values of predictors of observations with no anemia to the observations where any anemia was diagnosed. Next, we used MATLAB R2024a to train and test nine optimizable machine-learning classification models. These models were Ensemble, Tree, SVM, Efficient Linear, Neural Network, Kernel, KNN, Naïve Bayes, and the Discriminant. Bayesian optimization was used to optimize the hyperparameters of all these models. We used 90% of observations for training and 10% of observations for testing. During the training, 10-fold cross-validation was used to prevent overfitting. The results showed the best accuracy was reached with the Ensemble classification model using the bag ensemble method (validation accuracy: 99.22%, test accuracy: 100%). Finally, we inspected our best classification model in more detail. We calculated the permutation feature importance to determine the contribution of each predictor to the final model. The results showed 6–7 important predictors, while the most important feature was the amount of hemoglobin.