Natural history, spectrum and outcome of stage 3 AKI in patients with acute‐on‐chronic liver failure

There is limited data on natural course and interventions in stage‐3 acute kidney injury (AKI‐3) in patients with acute‐on‐chronic liver failure (ACLF). We studied the factors of AKI‐3 reversal and outcomes of dialysis in ACLF patients.

Consecutive patients with ACLF were prospectively enrolled (n = 1022) and variables determining AKI and its outcomes were analysed.

At 1 month, 337 (33%) patients had AKI‐3, of which, 131 had AKI‐3 at enrolment and 206 developed AKI‐3 during hospital stay. Of patients with AKI‐3 at enrolment, 18% showed terlipressin response, 21% had AKI resolution and 59% required dialysis. High MELD (≥35) (model 1), serum bilirubin (≥23 mg/dL) (model 2) and AARC score (≥11) (model 3) were independent risk factors for dialysis. Dialysis was associated with worse survival in all AKI patients but improved outcomes in patients with AKI‐3 (p = .022, HR 0.69 [0.50–0.95]). Post‐mortem kidney biopsies (n = 61) revealed cholemic nephropathy (CN) in 54%, acute tubular necrosis (ATN) in 31%, and a combination (CN and ATN) in 15%. Serum bilirubin was significantly higher in patients with CN, CN and ATN compared with ATN respectively ([30.8 ± 12.2] vs. [26.7 ± 12.0] vs. [18.5 ± 9.8]; p = .002).

AKI‐3 rapidly increases from 13% to 33% within 30 days in ACLF patients. Histopathological data suggested cholemic nephropathy as the predominant cause which correlated with high bilirubin levels. AKI‐3 resolves in only one in five patients. Patients with AARC grade 3 and MELD >35 demand need for early dialysis in AKI‐3 for improved outcomes.