Prognosis of probable autoimmune hepatitis patients: a single-center study in Japan

Autoimmune hepatitis (AIH) is an idiopathic inflammatory liver disease with genetic susceptibility and unknown environmental triggers. The gold standard for diagnosis, International Autoimmune Hepatitis Group (IAIHG) scoring system, classifies AIH as definite or probable. Conventional research on probable AIH has focused on the Caucasian population and there is little data pertaining to the Asian population. This study aimed to assess and compare the prognosis of Japanese patients with probable and definite AIH. In the current study, patients with probable and definite AIH diagnosed based on IAIHG scores between 1987 and 2018 were enrolled. As a result, 72 patients with definite AIH and 49 patients with probable AIH were evaluated. Univariate analysis revealed age, fibrosis stage 4, and the fibrosis-4 index were prognostic factors for overall survival. Multivariate analysis indicated that age and liver cirrhosis significantly affected the overall survival. When the cut off albumin-bilirubin score was set appropriately, cirrhosis was differentially diagnosed using albumin-bilirubin score with 100% sensitivity and 70.5% specificity. Classification of probable or definite disease did not alter overall survival with statistical significance. In conclusion, our findings suggest that probable AIH should be managed as definite AIH is managed in Japanese population. The albumin-bilirubin score helps identify liver cirrhosis and is a prognostic biomarker for overall survival.