The outcomes of critically ill patients with acute kidney injury receiving renal replacement therapy

Introduction: Acute kidney injury (AKI) is common among critically ill patients and associated with a high mortality. We report here on the outcomes of patients with AKI who received renal replacement therapy (RRT) on our intensive care unit (ICU). We were interested in which parameters measured at the time of ICU admission were predictive of mortality and the long term renal sequelae for these patients. Patients and Methods: All ICU patients in a large UK teaching hospital who received RRT for AKI over a 6-year period were identified and reviewed retrospectively. Results: There were 5582 admissions to ICU during this period of which 821 (14.7%) received RRT for AKI. The mean age was 59 years with ICU and hospital mortality rates of 55% and 66% respectively. Logistic regression analysis indicated that being older (OR 1.02 (1.01-1.03)) or having a lower pH (OR 0.07 (0.02-0.27)) or hemoglobin (OR 0.82 (0.74-0.91)) at the time of admission were predictive of mortality. Less than 7% of survivors were RRT dependant at hospital discharge and the majority had pre-existing renal impairment. For those patients with data available, there was a significant rise in the serum creatinine by 12 months post discharge (p<0.001). Conclusions: The mortality for critically ill patients receiving RRT for AKI is high, with two-thirds dying before hospital discharge. The requirement for long-term dialysis was 6.5% of survivors in our series which is much lower than that published elsewhere. Survivors of AKI who regained independent renal function had evidence of lasting renal injury.