Conjugated bilirubin in chronic liver disease: an underutilised prognostic biomarker?—a narrative review

Background and Objective: Chronic liver disease (CLD) is a major global health burden, often progressing to cirrhosis, decompensation, and hepatocellular carcinoma. Prognostic models typically rely on serum total bilirubin. However, recent evidence suggests that conjugated bilirubin (C-BIL) may offer superior prognostic utility in assessing disease severity and outcomes in CLD. This narrative review aims to examine the emerging evidence supporting C-BIL as a prognostic and disease stratification biomarker across various clinical contexts, where it has demonstrated enhanced predictive accuracy over traditional measures. Methods: A comprehensive, non-systematic review of the published literature was undertaken using major bibliographic databases and predefined keywords. Relevant studies were selected based on the following criteria: English-language publications, studies conducted in human populations, and articles with clear clinical applicability. Emphasis was placed on studies evaluating C-BIL in prognostic or disease-stratification contexts within CLD. Key Content and Findings: Emerging evidence indicates that incorporation of C-BIL into clinical prognostic models may enhance risk stratification and support more informed clinical decision-making in CLD. Elevated C-BIL appears to reflect impaired hepatocellular excretory function and fibrosis-related biliary obstruction. In addition, recent studies suggest that hepatocyte senescence may represent an additional, biologically plausible mechanism underpinning its prognostic relevance. Conclusions: This review highlights the potential clinical utility of C-BIL as a prognostic biomarker in CLD. While existing evidence supports its role in disease stratification and outcome prediction, further prospective validation and mechanistic studies are required before C-BIL can be adopted as a standard component of prognostic assessment in CLD.