Validating new coding algorithms to improve identification of alcohol-associated and nonalcohol-associated cirrhosis hospitalizations in administrative databases.

BACKGROUND: Alcohol (AC) and nonalcohol-associated cirrhosis (NAC) epidemiology studies are limited by available case definitions. We compared the diagnostic accuracy of previous and newly developed case definitions to identify AC and NAC hospitalizations. METHODS: We randomly selected 700 hospitalizations from the 2008 to 2022 Canadian Discharge Abstract Database with alcohol-associated and cirrhosis-related International Classification of Diseases 10th revision codes. We compared standard approaches for AC (ie, AC code alone and alcohol use disorder and nonspecific cirrhosis codes together) and NAC (ie, NAC codes alone) case identification to newly developed approaches that combine standard approaches with new code combinations. Using electronic medical record review as the reference standard, we calculated case definition positive and negative predictive values, sensitivity, specificity, and AUROC. RESULTS: Electronic medical records were available for 671 admissions; 252 had confirmed AC and 195 NAC. Compared to previous AC definitions, the newly developed algorithm selecting for the AC code, alcohol-associated hepatic failure code, or alcohol use disorder code with a decompensated cirrhosis-related condition or NAC code provided the best overall positive predictive value (91%, 95% CI: 87-95), negative predictive value (89%, CI: 86-92), sensitivity (81%, CI: 76-86), specificity (96%, CI: 93-97), and AUROC (0.88, CI: 0.85-0.91). Comparing all evaluated NAC definitions, high sensitivity (92%, CI: 87-95), specificity (82%, CI: 79-86), negative predictive value (96%, CI: 94-98), AUROC (0.87, CI: 0.84-0.90), but relatively low positive predictive value (68%, CI: 62-74) were obtained by excluding alcohol use disorder codes and using either a NAC code in any diagnostic position or a primary diagnostic code for HCC, unspecified/chronic hepatic failure, esophageal varices without bleeding, or hepatorenal syndrome. CONCLUSIONS: New case definitions show enhanced accuracy for identifying hospitalizations for AC and NAC compared to previously used approaches.

Acute severe hepatitis as a presenting symptom in clinically stable patients admitted with SARS-CoV-2 Omicron infection.

BACKGROUND: Suggested mechanisms for SARS-CoV-2 direct liver infection have been proposed by others to involve both cholangiocytes and hepatocytes. Early clinical studies have highlighted abnormal liver biochemistry with COVID-19 infection as often not being severe, with elevated liver enzymes <5X the upper limit of normal. METHODS: Liver enzymes were evaluated and compared in patients admitted with a diagnosis of COVID-19 in a deidentified Internal Medicine-Medical Teaching Unit/hospitalist admission laboratory database. Comparisons in the incidence of severe liver injury (alanine aminotransferase >10 times upper limit of normal) were made for patients with pre-Omicron SARS-CoV-2 (November 30, 2019, to December 15, 2021) and Omicron SARS-CoV-2 (December 15, 2021, to April 15, 2022). Comprehensive hospital health records were also reviewed for the 2 patient cases discussed. One patient had a liver biopsy that was evaluated with H&E and immunohistochemistry staining using an antibody against COVID-19 spike protein. RESULTS: The evaluation of a deidentified admissions laboratory database found the incidence of severe liver injury was 0.42% with Omicron versus 0.30% with pre-Omicron variants of COVID-19. In both patient cases discussed, abnormal liver biochemistry and a negative comprehensive workup strongly suggest COVID-19 as the cause of severe liver injury. In the one patient with liver biopsy, immunohistochemistry staining suggests SARS-CoV-2 presence in the portal and lobular spaces in association with immune cell infiltration. CONCLUSIONS: The Omicron variant of SARS-CoV-2 should be considered in the differential diagnosis of severe acute liver injury. Our observation suggests that this new variant, either through direct liver infection and/or mediating immune dysfunction, can result in severe liver injury.

ADAM Metalloproteinase Domain 17 Regulates Cholestasis-Associated Liver Injury and Sickness Behavior Development in Mice.

Disintegrin and metalloproteinase domain-containing protein 17 (ADAM17) is a ubiquitously expressed membrane-bound enzyme that mediates shedding of a wide variety of important regulators in inflammation including cytokines and adhesion molecules. Hepatic expression of numerous cytokines and adhesion molecules are increased in cholestatic liver diseases including primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), however, the pathophysiological role of ADAM17 in regulating these conditions remains unknown. Therefore, we evaluated the role of ADAM17 in a mouse model of cholestatic liver injury due to bile duct ligation (BDL). We found that BDL enhanced hepatic ADAM17 protein expression, paralleled by increased ADAM17 bioactivity. Moreover, inhibition of ADAM17 bioactivity with the specific inhibitor DPC 333 significantly improved both biochemical and histological evidence of liver damage in BDL mice. Patients with cholestatic liver disease commonly experience adverse behavioral symptoms, termed sickness behaviors. Similarly, BDL in mice induces reproducible sickness behavior development, driven by the upregulated expression of cytokines and adhesion molecules that are in turn regulated by ADAM17 activity. Indeed, inhibition of ADAM17 activity significantly ameliorated BDL-associated sickness behavior development. In translational studies, we evaluated changes in ADAM17 protein expression in liver biopsies obtained from patients with PBC and PSC, compared to normal control livers. PSC and PBC patients demonstrated increased hepatic ADAM17 expression in hepatocytes, cholangiocytes and in association with liver-infiltrating immune cells compared to normal controls. In summary, cholestatic liver injury in mice and humans is associated with increased hepatic ADAM17 expression. Furthermore, inhibition of ADAM17 activity improves both cholestatic liver injury and associated sickness behavior development, suggesting that ADAM17 inhibition may represent a novel therapeutic approach for treating patients with PBC/PSC.