['In the present study, we investigated the survival of patients who received postoperative renal replacement therapy (RRT) after cardiac surgery. We specifically focused on factors predicting long-term outcome in elderly patients.', 'Data of all patients that received unintentional renal replacement therapy following cardiac surgery between 2004 and 2010 were analyzed. Logistic- and Cox regression analyses were performed to detect the predictors of early and late mortality, respectively.', 'During the study period, 11,899 patients underwent cardiac surgery in our center. Post-operative RRT was performed in 138 patients (1.2%). In this group of patients, 30-day mortality included 72 patients (52%) and the total overall mortality included 107 patients (77.5%). Regression analyses revealed that age predicted 30-day mortality (odds ratio\u2009=\u20091.08 [1.03 to 1.12]) as well as late mortality (odds ratio\u2009=\u20091.05 [1.02 to 1.07].'] Does impact of postoperative renal replacement therapy on long-term outcome after cardiac surgery increase with age?