Validation of a Staging System for Acute Kidney Injury in Patients With Cirrhosis and Association With Acute-on-Chronic Liver Failure

BACKGROUND & AIMS: In patients with cirrhosis of the liver, acute kidney injury (AKI) is classified into 3 stages. Recent studies indicate that there are 2 subgroups of stage 1 disease, associated with different outcomes and serum levels of creatinine (SCr): stage 1A (SCr < 1.5 mg/dL) and stage 1B (SCr >= 1.5 mg/dL). We performed a prospective study to validate, in a large series of patients with cirrhosis, the association between this new description and patient outcomes, and assess the relationship between AKI stage and the presence of acute-on-chronic liver failure. METHODS: We collected data from 547 consecutive patients admitted for cirrhosis with acute decompensation to 2 tertiary hospitals (Italy and Spain), from February 2011 through June 2015. A total of 290 patients had AKI (53%; 197 had stage 1 disease); AKI stages were determined based on levels of SCr at diagnosis. Patients were followed up until death, liver transplantation, or for 90 days. The primary outcome was 90-day survival; secondary outcomes were progression and resolution of AKI and association with acute-on-chronic liver failure. RESULTS: Based on level of sCr at diagnosis, 58 patients had stage 1A disease and 139 had stage 1B disease. Of patients with stage 1A disease, 82% survived for 90 days; of patients with stage 1B disease, 55% survived for 90 days (P = .001). Hepatorenal syndrome and acute tubular necrosis were the most common causes of stage 1B AKI, and hypovolemia was the most common cause of stage 1A AKI. AKI progressed in a higher proportion of patients with 1B than 1A AKI (31% vs 15%; P = .017) and resolved in a higher proportion of patients with 1A disease (90% vs 52% of patients with stage 1B; P < .001). Stage 1B disease, but not 1A, was an independent predictor of AKI progression and mortality. ACLF developed in a significantly greater proportion of patients with stage 1B disease (76%) than stage 1A disease (22%; P < .001), which could account for the poor outcomes of patients with stage 1B disease. CONCLUSIONS: In a large group of patients with decompensated cirrhosis, we validated the association between AKI stages IA and IB (based on level of sCR) with survival times and AKI progression. We also associated these subgroups of AKI with development of acute-on-chronic liver failure. These findings are important for management of patients with decompensated cirrhosis.