Transient elastography in autoimmune hepatitis: Timing determines the impact of inflammation and fibrosis

BACKGROUND: There is an unmet need for the non-invasive monitoring of fibrosis progression in patients with autoimmune hepatitis (AIH).

AIMS: To assess the diagnostic performance of transient elastography in patients with AIH and to investigate the impact of disease activity on its diagnostic accuracy.

METHODS: Optimal cut-offs were defined in a prospective pilot-study (n=34) and the diagnostic performance of transient elastography validated in an independent second cohort (n=60). To explore the impact of disease activity on liver stiffness, patients were stratified according to biochemical response and the time interval between start of immunosuppression and transient elastography.

RESULTS: Liver stiffness strongly correlated with histological fibrosis stage (pilot-study: ρ = 0.611, p< 0.001; validation cohort: ρ=0.777, p<0.0001). ROC curves defined an AUROC of 0.95 for diagnosing cirrhosis at the optimal cut-off of 16 kPa. The performance of transient elastography was impaired when patients were analysed in whom transient elastography was performed within 3 months from start of treatment. In this setting, liver stiffness correlated with histological grading (ρ=0.558, p=0.001), but not with staging. In contrast, using the cut-off of 16 kPa, the accuracy for diagnosing cirrhosis was excellent in patients treated for 6 months or longer (AUROC 1.0).

CONCLUSIONS: Liver inflammation has a major impact on liver stiffness in the first months of AIH treatment. However, TE has an excellent diagnostic accuracy for separating severe from non-severe fibrosis after 6 months of immunosuppressive treatment.

LAY SUMMARY: Transient elastography (TE) is a special ultrasound scan, which assesses liver stiffness as a surrogate marker for liver fibrosis/scarring. Transient elastography has been shown to be a reliable non-invasive method to assess liver fibrosis in various chronic liver diseases, it takes less than 5 minutes and has a high patient acceptance. The current study validated for the first time this technique in a large cohort of patients with autoimmune hepatitis (AIH) and demonstrates that it is a reliable tool to detect liver fibrosis in treated AIH. For the monitoring of potential disease progression under treatment, the validation of liver stiffness as non-invasive marker of liver fibrosis will greatly improve patient care in autoimmune hepatitis.