Objective: Diabetic ketoacidosis is a severe disease condition causing fatalities in both type 1 and 2 diabetes. The management of this condition with fluid and insulin treatment is well documented. However, occurrence of rebound hyperglycemia and hypoglycemia is quite common. Therefore, we analyzed the serial peripheral blood sugar test results of patients who visited the emergency department with diabetic ketoacidosis to identify the relationship between these events and the severity of the disease or prognosis. Methods: One hundred twenty patients who were diagnosed with diabetic ketoacidosis visited the emergency department of a tertiary hospital with hyperglycemia from January 2018 to December 2020. Demographic and laboratory data of these patients were collected and analyzed retrospectively. The patients were divided into groups based on the occurrence and severity of acidosis, and a comparative study was conducted. Results: Of the patients surveyed, 70.8% presented with a rebound hyperglycemic or hypoglycemic event. After emergency treatment, 16 patients were admitted to the intensive care unit. The laboratory tests revealed that there were significant differences in the anion gap between the event and non-event groups. The analysis showed that previous medication, pre-existing chronic kidney disease, and malignancy were significant factors contributing to the severity of acidosis. Conclusion The episodes of rebound hyperglycemia or hypoglycemia were not significantly related to the results of emergency department treatment or the severity of acidosis. Patients with decreased consciousness initially or presence of chronic diseases could exhibit a relationship between these conditions and the severity of acidosis and irregular serial blood sugar change, but these do not inevitably lead to poor outcomes.