Incidence, prevalence, and causes of death of patients with autoimmune hepatitis: A nationwide register-based cohort study in Finland.

BACKGROUND

Epidemiological studies of autoimmune hepatitis are scarce and often based on single centre registries.

AIMS

We conducted a nationwide register study of incidence, prevalence, survival, and causes of death of autoimmune hepatitis patients in Finland.

METHODS

Autoimmune hepatitis cases 1995-2015 were retrieved from the national database of special reimbursements for drugs costs. Data on causes of death were retrieved from Statistics Finland.

RESULTS

After incomplete registration of AIH during the first years, the incidence of autoimmune hepatitis stabilised to 1.1/100,000 person-years (1.6 in women and 0.52 in men) in 2008-2015. The prevalence of autoimmune hepatitis at the end of 2015 was 14.3/100,000, 23.0/100,000 in women and 6.6/100,000 in men. The all-cause standardized mortality ratio (SMR) of autoimmune hepatitis patients was 1.81 (95% confidence interval (CI) 1.47-2.20). The SMR was increased in all age groups and in both sexes. The SMR for hepatocellular carcinoma was 20.6 (95% CI 10.3-36.8), and for digestive diseases in overall 13.5 (95% CI 8.2-20.8), constituting mainly from autoimmune hepatitis and liver cirrhosis.

CONCLUSION

Incidence of autoimmune hepatitis has remained stable, with clear female predominance. Autoimmune hepatitis is associated with a markedly increased risk of death with hepatocellular cancer forming the greatest risk.