Transient elastography reliably estimates liver fibrosis in autoimmune hepatitis

Abstract

Aim of the study: Autoimmune hepatitis (AIH) may result in liver fibrosis and cirrhosis. While the gold standard for staging fibrosis is biopsy, transient elastography (TE) represents a non-invasive alternative. TE has been validated in several chronic liver diseases, but no data exist to establish an association between histologic fibrosis on biopsy and TE liver stiffness measurements among a United States cohort of AIH patients. Material and methods: We conducted a retrospective cohort study of 53 AIH patients who received TE assessment and liver biopsy. Histologic fibrosis was classified as advanced (F3-F4) or mild/moderate (F0-F2). Liver stiffness by TE was measured in kilopascals (kPa). We performed a score test for trend to test the association between histologic fibrosis stage and increasing TE kPa categories. Analyses incorporated probe type (medium or extra-large) and body mass index (BMI). Linear regression was used to generate predicted associations between median kPa and histologic fibrosis score with the medium probe. Results: The cohort was primarily female (83%) with median age 56.3 years. Increasing kPa category was associated with worsening fibrosis stage when using the medium probe (p = 0.04), but not the extra-large probe (p = 0.40). BMI, however, differed between these groups (median 25.8 vs. 33.1, respectively, p < 0.001). In adjusted linear regression, increasing median kPa corresponded well to worsening fibrosis stage (p = 0.003). Conclusions: In a United States AIH cohort, increasing TE kPa measurements are associated with worsening histologic fibrosis staging. While medium probe performance was superior to the extra-large probe, significant variation in BMI between groups may explain this difference.