AKIKI2 Trial

The Lancet

April 3, 2021

Comparison of two delayed strategies for renal replacement therapy initiation for severe acute kidney injury (AKIKI 2): a multicentre, open-label, randomized, controlled trial.

Summarized by: 

Mazen Kherallah

What was the research question?

Is more delayed initiation of renal replacement therapy (RRT) in critically ill patients with severe acute kidney injury (KDIGO 3) associated in a better outcome in terms of more RRT-free days, compared with a delayed strategy.


How did they do it?

  • ·Multicenter, unblinded, randomized trial in 39 ICUs in France.

  • Patients with KDIGO 3 who had oliguria for more than 72 h or a blood urea nitrogen concentration higher than 112 mg/dL were randomized into two groups with 1:1 assignment.

  • 137 patients in the control group (delayed strategy): RRT started after meeting above criteria

  • 141 patients in the intervention group (more-delayed strategy): RRT initiation was postponed until mandatory indication (hyperkalaemia, metabolic acidosis, or pulmonary oedema) or until blood urea nitrogen concentration reached 140 mg/dL.

  • Patients with compelling need for RRT were excluded.

  • Primary outcome: days alive and RRT-free at 28 days post randomization in an intent to treat analysis.


What did they find?

  • The number of complications potentially related to acute kidney injury or to RRT were similar between groups.

  • No difference in the median number of RRT-free days between the more delayed vs the delayed group (12 days vs. 12 , p= 0.93).

  • Potential harm with more-delayed strategy: The hazard ratio for death at 60 days was 1·65 (95% CI 1·09–2·50, p=0·018).

  • The number of complications potentially related to acute kidney injury or renal replacement therapy did not differ between groups.

  • No difference was detected for the number of ventilator or vasopressor-fere days, length of stay, or the rate of renal recovery between the two groups.


Any limitations?

  • Likely underpowered as they estimated need of 270 patients for 80% power to detect a 4-day different in RRT-free days.

  • High risk of type II error (the null hypothesis rejected when it is in fact false: false negatives).


What does it mean?

  • Longer postponing of RRT in patients with acute kidney injury and oliguria or BUN >112 mg/dL, and no compelling need of immediate RRT did not confer additional benefit and was potentially harmful.

  • Intensivists should strongly consider initiating RRT in critically ill patients with acute kidney injury with no acute complications (hyperkalemia, fluid overload, or acidosis) within 72 hours of oliguria or BUN >112 mg/dL.

AKIKI2 Trial