Reliability of transient elastography for the detection of fibrosis in Non-Alcoholic Fatty Liver Disease and chronic viral hepatitis

Abstract

Transient elastography (TE) is validated in chronic hepatitis C (CHC) to evaluate hepatic fibrosis; however, limited data are available in chronic hepatitis B (CHB) and non-alcoholic fatty liver disease (NAFLD). This prospective study is aimed to assess the accuracy and the efficacy of TE for the detection of fibrosis in patients with chronic liver disease of different etiology and to evaluate the effect of steatosis on the liver stiffness measurement (LSM). TE was performed in 219 consecutive patients with chronic liver disease (35% CHC, 32% CHB, and 33% NAFLD) within 6 months of the liver biopsy. LSM was related to the fibrosis stage in each group (CHC: p = 0.596, p < 0.001; CHB: p = 0.418, p < 0.001; NAFLD: p = 0.573, p < 0.001), but the correlation was less strong in CHB and NAFLD than in CHC patients. In CHB patients with histological cirrhosis (F4), the median stiffness value was almost two times lower than in patients with severe fibrosis (F3). In NAFLD patients with advanced fibrosis (F3) and severe steatosis (> 33%), the LSM values were lower than expected and were similar to those of patients with initial fibrosis (F1) and fat < 33%. TE underestimated the stage of fibrosis in 75% of patients with F3 and steatosis > 33%. At multiple logistic regression analysis, in CHC and CHB patients, LSM was the only predictive variable of severe fibrosis/cirrhosis (OR = 1.42, p = 0.003 and OR = 1.354, p = 0.003, respectively), while in NAFLD subjects BMI and AST (OR = 1.433, p = 0.002 and OR = 1.053, p = 0.020, respectively) but not LSM were independently related with advanced fibrosis and cirrhosis. This study confirms that TE can be considered a valid support to detect fibrosis in chronic liver disease related to HCV but it should be interpreted cautiously in CHB and NAFLD patients, where host or disease-related factors may modify its accuracy.