Table 2 Comparison of key renal RRT studies in critically Ill patients with AKI

Early versus delayed initiation of RRT on mortality in critically ill patients with AKI (ELAIN) [6]

Single centre

RCT (2016)

231

KDIGO stage 2 AKI, NGAL > 150 ng/mL, ≥ 1 of: severe sepsis, vasopressor use, fluid overload or progression of other organ dysfunction

Early, RRT started within 8 h

OR

Late, RRT started 12 h after developing Stage 3 AKI*

90 Day Mortality. Early = 39.3%, Late = 57.4% (p = 0.03)

Artificial kidney initiation in kidney injury (AKIKI) study group [7]

Multicentre RCT (2016)

620

KDIGO Stage 3 AKI and mechanical ventilation or catecholamine infusion or both

Early, RRT started within 6 h

OR

Late, RRT started if oliguria persisted > 72 h*

60 Day Mortality. Early = 48.5%, Late = 49.7% (p = 0.79)

Initiation of dialysis early versus delayed in the intensive care unit (IDEAL-ICU) study [8]

Multicentre RCT (2018)

488

Septic shock and meeting RIFLE ‘F’ criteria

Early, RRT started within 12 h

OR

Late, RRT started after 48 h

90 Day Mortality. Early = 58%, Late = 54% (p = 0.38)

Standard versus accelerated initiation of RRT in AKI (STARRT-AKI) trial [9]

International Multicentre RCT (2020)

2927

KDIGO Stage 2 or 3 AKI

Accelerated RRT, within 12 h

OR

Standard, RRT started after 72 h*

90 Day Mortality, Accelerated = 43.9%, Standard = 43.7% (p = 0.92)

Comparison of two delayed strategies for RRT initiation for severe AKI (AKIKI 2): a multicentre, open-label, randomised, controlled trial [10]

Multicentre RCT (2021)

278

KDIGO Stage 3 AKI and mechanical ventilation or catecholamine infusion or both. Oliguria or anuria for > 72 h or BUN 112 – 140 mg/dL

Delayed group, RRT start in < 12 h. More delayed group, RRT postponed until BUN ≥ 140 mg/dL or urgent indication

RRT-free days

Delayed = 12 days

More delayed = 10 days

HR^# for death 60 days 1.65 (95% CI 1.09–2.50) for more delayed group