Renal Replacement Therapy -- Sooner or Later?

Greg Martin, MD


June 06, 2016

Initiation Strategies for Renal-Replacement Therapy in the Intensive Care Unit

Gaudry S, Hajage D, Schortgen F, et al; AKIKI Study Group
N Engl J Med. 2016 May 15. [Epub ahead of print]


Acute kidney injury (AKI) is a common and challenging condition to manage in critically ill patients, with many studies over the past decade attempting to better define, characterize, and optimize treatment. In particular, the timing of renal replacement therapy (RRT) in critically ill patients with AKI remains contentious.[1,2]

Gaudry and colleagues sought to determine whether earlier or later initiation of RRT would result in better outcomes in patients who were either mechanically ventilated or on vasopressors (or both) but without an acute indication for dialysis.[3] They randomly assigned 620 patients to initiate RRT either earlier (at randomization) or later (when an acute indication for dialysis arose).

There was no overall difference in 60-day mortality (48.5% vs 49.7%), and 49% of patients in the delayed group never initiated RRT. Catheter-related bloodstream infections were more frequent in the early RRT group (10% vs 5%; P=.03), and diuresis occurred earlier in the delayed RRT group.

The authors concluded that there was no difference in mortality with earlier RRT and that a delayed strategy often averted the need for RRT.


The major finding of this study is there are no differences in major clinical outcomes attributable to the timing of RRT initiation in critically ill patients, at least in those with the most severe AKI (Kidney Disease: Improving Global Outcomes [KDIGO] classification stage 3)[4] who are mechanically ventilated or on vasopressors (or both). Although those qualifiers could make a difference, it seems unlikely that the timing of RRT initiation would produce substantially better outcomes in different intensive care unit populations, such as patients with less severe AKI or those not on vasopressors.

Regardless, it appears that delayed initiation of RRT is superior in some respects. For example, at the individual patient level, delayed RRT resulted in earlier and more significant urine output (shown in this study particularly as a greater probability of adequate urine output). And from the perspective of providers and health systems, delayed RRT resulted in less use of dialysis by half. For critically ill patients with severe AKI, delayed initiation of RRT is appropriate, pending the development of an indication for more acute initiation.