Timing of Renal Replacement Therapy in Critically Ill Patients

Up to two thirds of critically ill patients develop acute kidney injury (AKI), and up to one in five require renal replacement therapy (RRT). Mortality increases with the severity of AKI, approaching 50% among patients requiring RRT.

The evidence for the optimal time to initiate RRT is conflicting. One major trial (ELAIN) showed a 90-day mortality benefit, while another (AKIKI) did not show a benefit at 60 days. The ELAIN trial was smaller, conducted almost exclusively in postoperative AKI patients, and the difference in timing between early versus late initiation of RRT was less than 24 hours. 

The IDEAL-ICU trial recently published in NEJM addressed this conflicting evidence. In this multicenter trial, investigators randomized 488 adults (mean age, 69 years) with septic shock and severe AKI (at the failure stage of the RIFLE classification) to receive RRT within 12 hours (early strategy) of documented failure stage or after a delay of 48 hours if kidney function did not improve spontaneously (late strategy). Nearly 90% of patients were receiving mechanical ventilation, all received vasopressor support, and nearly two thirds had oliguria or anuria.

Nearly all (97%) patients in the early-strategy group received RRT versus 62% in delayed-strategy group. Approximately 30% of patients in the delayed-strategy group had spontaneous recovery of renal function and therefore did not receive RRT. The median time from diagnosis of AKI to initiation of RRT was earlier in the early-strategy group than in the delayed-strategy group (7.6 vs. 51.5 hours; P<0.001).

The IDEAL-ICU trial was stopped early for futility. The primary outcome of mortality at 90 days did not differ between patients who received early versus late initiation of RRT (58% vs. 54%; P=0.38). Furthermore, no benefits were seen from early initiation of RRT in secondary outcomes of mortality at 28 and 180 days and median length of ICU or hospital stay.

What is my take away?

Early renal replacement therapy in patients with septic shock and severe acute kidney injury did not lower 90-day mortality in the IDEAL-ICU trial.

Browse more From Pages to Practice »

James Yeh, MD MPH is an internist and assistant in medicine at the Massachusetts General Hospital and an instructor in medicine at Harvard Medical School. His clinical and academic interests are in evidence-based medicine, medical education, continuing medical education, cardiopulmonary diseases, cardiovascular risk reduction, critical illness, care transition, polypharmacy, and health communication. He was a NEJM editorial fellow in 2015-2016.