Preprocessing Handling to Enhance Detection of Type 2 Diabetes Mellitus based on Random Forest

Diabetes is a non-communicable disease that has a death rate of 70% in the world. Majority of diabetes cases, 90-95%, are of diabetes cases are type 2 diabetes which is caused by an unhealthy lifestyle. Type 2 diabetes can be detected earlier by using examination that contains diabetes-related parameters. However, the dataset does not always contain complete information, the distribution between positive and negative classes is mostly imbalanced, and some parameters have low importance to the decision class. To overcome the problems, this study needs to carry out preprocessing to improve detection precision and recall. In this paper, propose an approach on dataset preprocessing, which is applied to diabetes prediction. The preprocessing approach consists of the following process: missing value process, imbalanced data process, feature importance process, and data augmentation process. The data preprocessing process uses the median for missing value, random oversampling for imbalanced data, the Gini score in the random forest for feature importance, and posterior distribution for data augmentation. This research used random forest and logistic regression as classification algorithms. The experimental results show that the classification increased by 20% precision and 24% recall by applying proposed method and random forest method compared to without proposed method and random forest method.