Impact of Renal Replacement Therapy on Mortality and Renal Outcomes in Critically Ill Patients with Acute Kidney Injury: A Population-Based Cohort Study in Korea between 2008 and 2015

The outcomes depending on the type of renal replacement therapy (RRT) or pre-existing kidney disease in critically ill patients with acute kidney injury (AKI) have not been fully elucidated. All adult intensive care unit patients with AKI in Korea from 2008 to 2015 were screened. A total of 124,182 patients, including 21,165 patients with pre-existing kidney disease, were divided into three groups: control (no RRT), dialysis, and continuous RRT (CRRT). In-hospital mortality and progression to end-stage kidney disease (ESKD) were analyzed according to the presence of pre-existing kidney disease. The CRRT group had a higher risk of in-hospital mortality. Among the patients with pre-existing kidney disease, the dialysis group had a lower risk of in-hospital mortality compared to other groups. The risk of ESKD was higher in the dialysis and CRRT groups compared to the control group. In the CRRT group, the risk of ESKD was even higher in patients without pre-existing kidney disease. Although both dialysis and CRRT groups showed a higher incidence of ESKD, in-hospital mortality was lower in the dialysis group, especially in patients with pre-existing kidney disease. Our study supports that RRT and pre-existing kidney disease may be important prognostic factors for overall and renal outcomes in patients with AKI.