The effect of hemodialysis treatment on mortality in patients with acute renal disease in intensive care unit

Background and aims: Acute kidney disease (AKI) is a condition caused by uremic toxins due to impaired renal functio and a reduction in glomerular filtration rate within hours to days. The development of AKI is very common in patients followed up in the intensive care unit (ICU) and has high morbidity and mortality rates. Especially due to the severity of renal insufficiency, the mortality rate in intensive care patients can reach from 30% to 90%, and at the same time, it is seen that prolonged stay in the ICU. The aim of this study was to investigate the effect of hemodialysis, which is commonly used as renal replacement therapy in patients with AKI, on mortality in intensive care patients. Patient scoring systems in the ICU are widely used to predict recovery from disease, determine the severity of the patient and organ dysfunction, evaluate treatment, and compare the performance of intensive care units. In the study, APACHE II score was used to determine the mortality risks of ICU patients. Materials and methods: Patients who were hospitalized due to AKI or who developed AKI after hospitalization in the Intensive Care Unit at Bülent Ecevit University Faculty of Medicine were included in the study. AKI was classified according to ERBP (Europen Renal Best Practice) criteria and mortality risk were determined by APACHE II (Acute Physiology and Chronic Health Evaluation II) scoring. Data of 104 patients were collected using the retrospective method. The patients were divided into two groups as HD and non-HD. In these two main groups, the reason for hospitalization, the use of angiotensin-converting enzyme inhibitor (ACEI), the use of diuretics, the use of radiocontrast agents or antibiotics, chronic diseases (with or without DM), the need for renal replacement therapy (RRT), mechanical ventilator (MV) support, basal urea and creatinine levels and urea and creatinine levels at admission were evaluated. Routine HD patients, the patients with a history of transplant and malignancy, hospitalization less than 24 hours and exitus within 48 hours were excluded. This study aimed to show the effect of hemodialysis treatment on mortality in patients with AKI in the intensive care unit. Results: The ages of the patients were between 18-95 and the mean age was 73.6 ± 13.4 years. The 104 patients, 62 male, and 42 female were included. When we evaluated the patients according to the reason of their admission to the intensive care unit, the largest groups consisted of 31 patients with infectious causes, 24 patients with AKI and 18 patients with acute respiratory failure. 76.9% of 70 patients supported with MV were in stage 3 according to ERBP classification. It was detected that the mortality rate of patients supported with MV and had stage 3 renal injury increased significantly (p = 0.04). And also, it was observed that the patients with AKI did not need RRT in stage 1 and stage 2, and needed RRT in stage 3 (p <0.001). APACHE II scores within 24 hours of admission were recorded. The mean APACHE II score was 28.07 ± 6.99. APACHE II scores were higher in stage 1 and stage 3 (p = 0.005). Patients were evaluated according to the APACHE II score, in terms of RRT requirement and mortality. The percentage of patients' expected mortality rate increased in direct proportion to the APACHE II score. It was demonstrated by the cox regression method that RRT did not affect mortality. When the patients were subdivided according to the APACHE II score, the observed mortality rate was higher than expected in five subgroups. The most likely reasons for this situation may be a large number of patients receiving MV support, prolonged ICU stays, the presence of comorbid diseases, and delayed initiation of supportive treatment due to pre-hospital delays. Besides, the majority of patients in ICU having sepsis (multi-organ failure) could be considered as another reason. Conclusion: As a result of our study, following the literature, receiving early hemodialysis has no positive effect on the mortality rates in critically ill patients who were admitted to the intensive care unit with acute kidney injury. However, there is a significant relationship between mortality rate and severity of acute renal injury, prolonged hospital stay, support of mechanical ventilation, multi-organ failure, and high APACHE II score. Key words: Acut kidney injury, hemodialysis, mortality, APACHE II score, ERBP classification