Epidemiology, comorbidities, treatments and outcomes of autoimmune liver diseases: A French nationwide study.

Background & Aims: The epidemiology, clinical management, and prognosis of autoimmune liver diseases (AILDs) - including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) - vary according to geography and time. This study aimed to provide a comprehensive evaluation of the burden of AILDs in a Western European country. Method: A nationwide retrospective study was performed using the French national health data system from 2009 to 2019. AIH and PBC were identified via ICD-10 codes, while PSC was defined using composite criteria. Prevalence, incidence, geographic patterns, comorbidities, treatments, liver transplant, and standardized mortality ratio were assessed. Results: A total of 30,255 AILD cases were identified, representing 5% of chronic liver disease cases. The prevalence per 100,000 inhabitants was 14.9 for AIH, 15.0 for PBC, and 4.2 for PSC. Geographic variation was observed, with significant regional clustering of AIH and PBC cases. The incidence of AIH increased significantly over time, whereas that of PBC and PSC declined. Patients with AILDs exhibited higher rates of diabetes and all-cause malignancies compared to the general population. Ursodeoxycholic acid was underprescribed in PBC, while corticosteroids were frequently overused in both PBC and PSC, and ursodeoxycholic acid in AIH. Liver transplantation was performed four times more often in PSC than in either AIH or PBC. All AILDs were associated with elevated 10-year standardized mortality ratios: 1.80 for AIH, 1.74 for PBC, and 2.59 for PSC. Conclusion: These findings confirm the rising incidence of AIH - but not PBC or PSC - the non-random geographic distribution of AIH and PBC, a higher risk of diabetes and cancer across all AILDs, and persistent excess mortality despite current treatment options. Impact and implications: The true burden of autoimmune liver diseases (AILDs) remains inadequately characterized. In this extensive study conducted in France, based on health insurance and hospital records collected between 2009 and 2019, we characterized the epidemiology, comorbidities, treatments and outcomes of autoimmune hepatitis, primary biliary cholangitis and primary sclerosing cholangitis. We confirm the rising incidence of AIH, the non-random geographic distribution of both autoimmune hepatitis and primary biliary cholangitis, the elevated risk of diabetes and cancer, and a persistently increased mortality across all AILDs - most notably in primary sclerosing cholangitis, where both excess mortality and the need for liver transplantation is higher than in other AILDs. These findings highlight the persistent gaps and unmet needs in the management of AILDs.