Today, the existence of a vast amount of electronic health data has created potential capacities for conducting studies aiming to improve the medical services provided to patients and reduce the costs of the healthcare system. One of the topics that has been receiving attention in the field of medicine in recent years is the identification of patients who are likely to be re-hospitalized shortly after being discharged from the hospital. This identification can help doctors choose appropriate treatment methods, thereby reducing the rate of patient re-hospitalization and resulting in effective treatment cost reduction. In this study, the prediction of patient re-hospitalization using text mining approaches and the processing of discharge report texts in the patient's electronic file has been discussed. To this end, the performance of various machine learning models has been evaluated using two approaches: bag of word and bag of concept, in the process of predicting patient readmission. Comparing the efficiency of these approaches has shown the superiority of the random forest model and the bag of concept approach over other machine learning models and approaches. This research has achieved the highest score in predicting the probability of patient re-hospitalization, with a recall score of 68.9%, compared to similar works that have utilized machine learning models in this field.