Abstract

Background and aims: Acute kidney injury (AKI) in cirrhosis is morbid, but the incidence rates of different etiologies of AKI are not well described in United States patients. We compared incidence rates, practice patterns, and outcomes across etiologies of AKI in cirrhosis.

Methods: Retrospective cohort study of 11 hospital networks of consecutive adult patients admitted in 2019 with AKI and cirrhosis. Etiology of AKI was adjudicated based on pre-specified clinical definitions (prerenal/hypovolemic AKI, hepatorenal syndrome [HRS-AKI], acute tubular necrosis [ATN], other).

Results: 2,063 patients were included (median age 62 [IQR 54, 69] years, 38.3% female, median MELD-Na score 26 ^19,31). The most common AKI etiology was prerenal AKI (44.3%), followed by ATN (30.4%) and HRS-AKI (12.1%); 6.0% had other AKI, and 7.2% were unable to classify. 8.1% patients received a liver transplant, 36.5% died by 90-days. Patients with prerenal AKI had the lowest rate of death (22.2%; p <0.001) whereas patients with HRS-AKI and ATN were higher, but not significantly different from each other (49.0% vs. 52.7%; p = 0.42). Using prerenal AKI as reference, the adjusted sHR for 90-day mortality was higher for HRS-AKI (sHR 2.78 [95% CI 2.18-3.54]; p <0.001) and ATN (sHR 2.83 [2.36-3.41]; p <0.001). In adjusted analysis, higher AKI stage and lack of complete response to treatment was associated with an increased risk of 90-day mortality (p <0.001 for all).

Conclusion: AKI is a severe complication of cirrhosis. HRS-AKI is uncommon and has similar outcomes to ATN. Etiology of AKI, AKI stage/severity, and non-response to treatment were associated with mortality. Further optimization of vasoconstrictors for HRS-AKI and supportive therapies for ATN are needed.

Impact and implications: Acute kidney injury (AKI) in cirrhosis carries high morbidity, and management is determined by etiology of the injury. However, a large and well-adjudicated multicenter database from U.S. centers that uses updated AKI definitions is lacking. Our findings demonstrate that acute tubular necrosis and hepatorenal syndrome have similar outcomes (∼50% mortality at 90 days), though hepatorenal syndrome is uncommon (12% of all AKI cases). These findings represent practice patterns at U.S. transplant/tertiary centers and can be used as a baseline prior to the U.S. adoption of terlipressin.