Bile Cast Nephropathy in Patients with Acute Kidney Injury Due to Hepatorenal Syndrome: A Postmortem Kidney Biopsy Study.

Background and Aims: The role of bile cast nephropathy (BCN) in pathogenesis of hepatorenal syndrome (HRS) in decompensated cirrhosis and acute on chronic liver failure (ACLF) is unknown. This study aimed to determine the frequency of BCN detected on postmortem renal biopsy among patients with decompensated cirrhosis and ACLF who had been admitted with acute kidney injury due to HRS (HRA-AKI) and expired during that hospitalization. Methods: One-hundred-twenty-seven postmortem renal biopsies with adequate size (>1 cm in length) were included for analysis. These were obtained from 84 patients with decompensated cirrhosis and 43 patients with ACLF. Results: BCN was detected in 57 of the total 127 (44.8%) renal biopsy specimens. Patients with BCN had significantly higher levels of serum total bilirubin, total leukocyte count and model for end-stage liver disease score, as compared to those without BCN. BCN was detected in 32/43 (74.4%) of the patients with ACLF, as compared to 25/84 (29.7%) of the patients with decompensated cirrhosis (p < 0.001). On multivariate analysis, direct bilirubin (OR (95% CI): 1.27 (1121-1.698); p < 0.001) and presence of ACLF (OR (95% CI): 2.603 (1.054-7.111); p = 0.041) were found to be significant predictors of BCN on postmortem renal biopsy. Conclusion: BCN was found in 72.1% of patients with ACLF and 27.4% patients with decompensated cirrhosis who had been hospitalized with an admitting diagnosis of HRS-AKI and who expired during that hospitalization and underwent postmortem renal biopsy. Direct serum bilirubin and presence of ACLF were found to be significant predictors of BCN on postmortem renal biopsy.