Purpose: Identification of risk factors for impaired renal function at hospital discharge in critically ill patients with acute kidney injury (AKI) requiring renal replacement therapy (RRT). Methods: A single-center retrospective cohort study was performed evaluating demographic and clinical parameters as potential risk factors for a modest to severely impaired renal function at hospital discharge in patients with AKI requiring RRT in the intensive care unit. Results: Of the 353 patients in our cohort, 90 (25.5%) patients had pre-existing chronic kidney disease (CKD). An estimated glomerular filtration rate (eGFR) <= 60 mL min(-1) 1.73 m(-2) at hospital discharge occurred in 64.0% of which 63.7% without known renal impairment before hospital admission and 8.2% of all cases left the hospital dialysis-dependent. Multivariable logistic regression showed that age (OR = 1.051, P < .001), serum creatinine concentration at start of RRT (OR = 1.004, P < .001 Conclusions: Elderly and patients with pre-existing CKD are at a high risk for modest to severely impaired renal function at hospital discharge after AKI requiring RRT. (C) 2013 Elsevier Inc. All rights reserved.