Evolutionary relationship between antimitochondrial antibody positivity and primary biliary cholangitis in Taiwan: a 16-year hospital cohort study

Background: How antimitochondrial antibody (AMA)-positive patients evolve to have primary biliary cholangitis (PBC) in viral hepatitis–endemic areas is unknown. Objectives: We aimed to investigate this evolution in Taiwan. Design/methods: A 16-year medical center-based cohort study of 2,095,628 subjects was conducted in Taiwan, an Asian country endemic to viral hepatitis. AMA-positive subjects were those with positive AMA with alkaline phosphatase (ALP) ⩽1.5 times the upper limit of normal (ULN), and PBC was defined as positive AMA with ALP >1.5 × ULN. Results: AMA-positive subjects had a lower average age- and sex-adjusted prevalence than PBC patients (4.68/105 versus 11.61/105, p = 0.0002), but their incidence was comparable (0.99/105 versus 1.12/105, p = 0.36). The former group had a borderline significantly lower mean age (56.59 years versus 58.10 years, p = 0.06) and a lower female-to-male ratio (2.85:1 versus 5.44:1, p