Intensity of continuous renal-replacement therapy.
To the Editor: In the Randomized Evaluation of Normal versus Augmented Level (RENAL) Replacement Therapy Study (Oct. 22 issue),1 investigators compared low-intensity versus high-intensity renal-replacement therapy. One of the secondary outcomes was the development of new organ failure. However, the criteria for “nonrenal organ failure” were not provided. Second, in subgroup analyses, the RENAL study showed that there was no mortality benefit with high-intensity treatment in patients with sepsis, cardiovascular dysfunction, or failure of at least one nonrenal organ. In a study involving 1847 critically ill patients receiving renal-replacement therapy, we recently reported that the number of failed organ systems at the time of such therapy had a significant effect on the rate of death in the intensive care unit, ranging from 38% in patients with one organ failure to 85.6% in patients with more than three failed organ systems.2 The RENAL study was not designed to perform subgroup analyses in patients with three or more associated failed organ systems. The question remains whether renal-replacement therapy should be individualized in patients with acute kidney injury and multiorgan failure and whether there is a role for high-intensity renal-replacement therapy in this group.