Hepatic inflammation may influence liver stiffness measurements by transient elastography in children and young adults

Objectives: Transient elastography (TE) measures liver stiffness to assess fibrosis. Studies in adults have shown that inflammation increases stiffness, leading to an overestimation of fibrosis. We investigated the contribution of inflammation to liver stiffness measurements (LSMs) in children/young adults. Methods: This was a cohort analysis of children/young adults who underwent TE within 1 year of liver biopsy. Alanine aminotransferase (ALT) was obtained within 30 days of the biopsy and LSM. Fibrosis was assessed by METAVIR stage and inflammation by ALT and Ishak score. Data were stratified into METAVIR F0-F2 versus F3-F4. Change between ALT and LSM over time was also assessed. Results: A total of 154 patients (50% male patients) ages 3 weeks to 24 years (18% <3 years) were studied. Diagnoses included autoimmune (N=38, 25%), viral (N=25, 16%), cholestasis (N=17, 11%), fatty liver (N=9, 6%), biliary atresia (N=8, 5%), metabolic (N=5, 3%), allograft rejection (N=4, 3%), and other (N=48, 31%). Thirty-four percent of patients had F3-F4. In patients with F0-F2, the proportion of those with LSM >8.6 kPa increased with increasing ALT (P=0.002). In patients with F3-F4, there was no association between ALT and LSM (P=0.17). A correlation between change in ALT and LSM was observed in patients with no/minimal fibrosis and inflammatory liver diseases (r=0.33). Conclusions: In children with no/minimal hepatic fibrosis and inflammatory liver disease, high ALT values are associated with LSM in the range typical of advanced fibrosis. However, with more advanced fibrosis, inflammation does not appear to contribute to LSM. Caution must be taken when interpreting LSM for assessing fibrosis severity in the setting of inflammation.