Risk factors and outcomes of acute kidney injury in patients with acute liver failure.

BACKGROUND & AIMS: Patients with acute liver failure (ALF) frequently develop renal dysfunction, yet its overall incidence and outcomes have not been fully assessed. We investigated the incidence of acute kidney injury (AKI) among patients with ALF, using defined criteria to identify risk factors and to evaluate its effect on overall outcomes.

METHODS: We performed a retrospective review of data from 1604 patients enrolled in the Acute Liver Failure Study Group, from 1998 through 2010. Patients were classified by the Acute Kidney Injury Network criteria, as well as for etiology of liver failure (acetaminophen-based, ischemic, and all others).

RESULTS: Seventy percent of patients with ALF developed AKI, and 30% received renal replacement therapy (RRT). Patients with severe AKI had higher international normalized ratio values than those without renal dysfunction (P < .001), and a higher proportion had advanced-grade coma (coma grades 3 or 4; P < .001) or presented with hypotension requiring vasopressor therapy (P < .001). A greater proportion of patients with acetaminophen-induced ALF had severe kidney injury than of patients with other etiologies of ALF; 34% required RRT, compared with 25% of patients with ALF not associated with acetaminophen or ischemia (P < .002). Of the patients with ALF who were alive at 3 weeks after study entry, significantly fewer with AKI survived for 1 year. Although AKI reduced the overall survival time, more than 50% of patients with acetaminophen-associated or ischemic ALF survived without liver transplantation (even with RRT), compared with 19% of patients with ALF attribute to other causes (P < .001). Only 4% of patients requiring RRT became dependent on dialysis.

CONCLUSIONS: Based on a retrospective analysis of data from more than 1600 patients, AKI is common in patients with ALF and affects short- and long-term outcomes, but rarely results in chronic kidney disease. Acetaminophen-induced kidney injury is frequent, but patients have better outcomes than those with other forms of ALF.