Association between Serum Cytokeratin-18 Neoepitope M30 (CK-18 M30) Levels and Chronic Hepatitis B: A Meta-Analysis

Background: Cytokeratin-18 Neoepitope M30 (CK-18 M30) has been reported to be associated with chronic HBV infection and severity of liver injury; however, the results of these studies are inconsistent. Objectives: We sought to investigate the association between serum CK-18 M30 levels and the severity of liver injury in chronic hepatitis B (CHB) patients. Methods: A systematic literature search was performed in PubMed, Embase, and Cochrane Library databases for relevant studies published in English up to August 2017. Heterogeneity among individual studies was investigated for summarizing all the studies. The standard mean difference (SMD) and 95% confidence interval (CI) were calculated using a random-effects model or fixed-effects model. Finally, the sensitivity analysis and publication bias were performed to evaluate the accuracy of this meta-analysis. Statistical analysis was conducted using Review Manager 5.3 and Stata 12.0. Results: Five case-control studies were included in the ultimate analysis, recruiting 488 CHB patients, 276 inactive carriers, and 193 healthy controls. The major results of the meta-analysis revealed significantly elevated serum CK-18 M30 levels in chronic HBV infected patients including CHB patients with severe liver injury and inactive HBV carriers when compared to healthy controls (SMD = 1.13, 95% CI: 0.75 - 1.50, P < 0.001; SMD = 0.63, 95% CI: 0.38 - 0.89, P < 0.001, respectively). Furthermore, the serum CK-18 M30 levels were significantly higher in CHB patients with severe liver injury than in inactive carriers (SMD =1.29, 95% CI: 0.60 - 1.98, P < 0.001). The sensitivity and publication bias analysis verified the stability and reliability of our analysis. Conclusions: The elevated serum CK-18 M30 levels could be regarded as a useful non-invasive biomarker for the diagnosis of chronic HBV infection, and were associated with the severity of liver injury in chronic Hepatitis B patients. The serum CK-18 M30 levels could reflect the liver inflammation in inactive carriers, representing the early stage of chronic HBV infection.