AbstractBackground and AimsUp to 30% of patients with severe alcoholic hepatitis (sAH) die within 3 months of presentation. The degree of ductular reaction, characterized by accumulation of biliary and liver progenitor cells, confers a poor prognosis. Keratin fragments are established serological surrogates of liver injury and keratin 19 (K19) is a histological marker of the ductular reaction. We assessed the relationship between serum K19 levels (viz. CYFRA21‐1), histology and outcome in patients with sAH.MethodsSerum CYFRA21‐1 was quantified in pre‐treatment serum samples from 824 patients enrolled in the STOPAH trial. The cohort was randomly divided into two groups to test mortality associations; histological analyses were performed using the 87 cases with suitable samples.ResultsCYFRA21‐1 levels were elevated in sAH and strongly predicted alcoholic steatohepatitis (ASH) on biopsy (area under the receiver operated characteristic [AUROC] 0.785 [95% Confidence Interval 0.602–0.967]) and 90‐day survival (AUROC 0.684/0.693). The predictive ability of CYFRA21‐1 was comparable with the model of end‐stage liver disease (MELD) score and was independently associated with survival in multivariable analysis. CYFRA21‐1 moderately correlated with hepatocellular injury markers M30/M65 but displayed a more robust predictive ability. A combination of MELD and CYFRA21‐1 conferred a modest improvement in the AUROC value (0.731/0.743).ConclusionsIn sAH serum, CYFRA21‐1 levels associate with the presence of ASH on biopsy and independently predict 90‐day survival. As a single marker performance is comparable to established scoring systems. Therefore, CYFRA21‐1, which is available in many clinical laboratories, may become a useful component of prognostic models.