Serum keratin-18 detects hepatic inflammation and predicts progression in compensated alcohol-associated liver disease.

Alcohol-associated liver fibrosis accumulates over decades, driven by hepatic inflammation and cell death. We investigated the diagnostic accuracy of keratin-18 degradation, measured using serum M30 and M65 levels, and the ActiTest for hepatic inflammatory activity in patients with compensated alcohol-associated liver disease (ALD). Furthermore, we evaluated the prognostic accuracy of markers for liver-related events and all-cause mortality. All findings were compared with routine liver function tests: Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyltransferase. Our prospective, biopsy-controlled, single-center study included 265 patients with ongoing or prior excessive alcohol intake, representing the full spectrum of compensated ALD. We defined hepatic inflammatory activity as a combined score of lobular inflammation and ballooning. For severe hepatic inflammatory activity (n = 40), we found excellent diagnostic accuracy for M30 (area under the receiver operating characteristics curve [AUROC] = 0.90), M65 (AUROC = 0.86), and AST (AUROC = 0.86). Elevated M30 (M30 > 240 U/L) had the highest positive predictive value (PPV) and specificity, significantly higher than M65, ActiTest and ALT, but not AST (M30: sensitivity = 83%, specificity = 82%, positive predictive value = 45%, negative predictive value = 95%). Patients were followed up for 1445 patient-years. All markers, except for ALT, significantly predicted liver-related events and all-cause mortality. After adjusting for advanced fibrosis, drinking behavior and body mass index, M30 and M65 remained significant predictors of liver-related events, whereas M30 and AST were significant predictors of all-cause mortality. Conclusion: M30 and AST accurately detect severe hepatic inflammatory activity in patients with compensated ALD. M30 was the only significant predictor of both liver-related events and all-cause mortality after adjusting for advanced fibrosis, body mass index, and drinking behavior at inclusion.