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.
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.
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.