Characteristic geoepidemiology and phenotype of autoimmune hepatitis: an 8-year population-based study in Taiwan

Data on the geoepidemiology and phenotype of autoimmune hepatitis (AIH) among individuals in Asia are limited.

AIH patients were identified from the Taiwan National Health Insurance administrative database (n=24,867,461) with the ICD-10 CM code K75.4.

A total of 8909 AIH patients (females, n=6018) were included. The average age- and sex-adjusted prevalence (2016-2023) and incidence rates (2017-2023) were 20.505 per 100,000 population and 4.739 per 100,000 population per year, respectively. The overall annual percentage changes for prevalence and incidence were 25.56% (p<0.0001) and 4.85% (p<0.0001), respectively. Compared with AIH patients in southern Taiwan, AIH patients in northern Taiwan accounted for the majority (72.70%) and were younger at diagnosis (54.17 vs. 55.62 years, p=0.0011). The 8-year liver cirrhosis (LC), hepatocellular carcinoma (HCC), liver transplantation (LT), mortality and LT-free mortality cumulative incidence rates (CIRs) were 19.21%, 3.78%, 1.48%, 21.12% and 20.93%, respectively. The 8-year CIRs for hypertension, hyperlipidemia and diabetes were 44.77%, 46.84%, and 32.24%, respectively, and these diseases were the most common extrahepatic diseases. Lower hepatic and cardiometabolic complications and mortality but higher autoimmune complication CIRs were detected in northern than in southern Taiwan AIH patients. Higher hepatic and autoimmune complications but lower cardiometabolic complications and mortality CIRs were detected in female than in male AIH patients. Sex, age, residency, income, hepatic complications, diabetes and hyperlipidemia were associated with LC; sex, age, LC, ascites and diabetes were associated with HCC; and sex, age, residency, income, diabetes, hepatic complications, hyperlipidemia, systemic lupus erythematosus, thyroid diseases, systemic sclerosis and non-HCC cancers were associated with LT-free mortality.

In Taiwan, the prevalence and incidence rates of AIH have increased over time. Care tailored to the patient's sex, age, residency, income and different complications is needed to improve outcomes.