Hepatic Steatosis And Necro-Inflammato ry Activity Overestimate Liver Stiffness by Transient Elastography in Staging Liver Fibrosis in Chronic Hepatitis C

Introduction: Transient Elastography (TE) is a non-invasive method to evaluate liver fibrosis by measuring Liver Stiffness (LS). However, its role in the full management of chronic hepatitis C patients is not completely appraised as well as its limitations are scantly explored. In particular the impact of liver steatosis and necro-inflammatory activity require being more investigated. Thus, this study was aimed to further assess the reliability of TE in evaluating liver fibrosis and the impact of hepatic necro-inflammatory activity and steatosis on the performance of TE. Patients and Methods: Enrolled were 258 consecutive patients with chronic hepatitis C who underwent to liver biopsy. Hepatic fibrosis was scored according to METAVIR, steatosis and necro-inflammatory activity were also scored. LS ranges were defined according to Castéra. Concordance between liver biopsy and TE was evaluated by Kappa index test. The performance of TE was assessed by ROC curves and by calculating AUROC. Factors independently associated with LS were weight up by logistic regression analysis. Results: The data showed a high diagnostic accuracy of TE for severe fibrosis (≥F3) with an AUROC of 0.80 and 0.95 for F3 and F4, respectively, with a high specificity and sensitivity; but a lower efficiency in discriminate F1 from F2. At univariate analysis TE showed a relationship with liver fibrosis (p<0.0001),liver inflammation (p<0.0001) and steatosis (p<0.006).Overall, multivariate analysis showed that factors independently associate with LS were liver fibrosis (p<0.0001) and inflammation (p<0.005), whereas, steatosis (p<0.005) was independently associated with LS in patients with fibrosis lower then F3. Conclusion: Our study confirms that TE is a reliable tool to individuate chronic hepatitis C patients with advanced liver fibrosis or cirrhosis, but it has lesser accuracy for earlier stages of liver fibrosis. Furthermore, high levels of liver necro-inflammatory activity overestimate LS and steatosis induces misevaluation of LS by TE in non-cirrhotic patients.