Abstract
BACKGROUND: Autoimmune liver diseases, including primary biliary cholangitis (PBC) and autoimmune hepatitis (AIH), are rare chronic conditions with significant morbidity. However, population-based epidemiological data from Latin America remain limited. This study aimed to describe the geographic distribution and demographic patterns of PBC and AIH in Colombia between 2018 and 2024. METHODS: A descriptive, cross-sectional population-based study was conducted using data from the Comprehensive Social Protection Information System (SISPRO) of the Colombian Ministry of Health. Individuals with at least 1 recorded diagnosis coded as K74.3 (PBC) or K75.4 (AIH) according to the International Classification of Diseases, 10(th) Revision (ICD-10), were identified. Administrative prevalence estimates were calculated per 100,000 population, using official population projections from the National Administrative Department of Statistics (DANE). Age- and sex-specific distributions were analyzed, and geographic variation was visualized using choropleth maps at the regional level. RESULTS: A total of 6504 PBC cases and 11,225 AIH cases were identified. The estimated national administrative prevalence was 14.7 per 100,000 population for PBC and 17.0 per 100,000 for AIH. Both conditions showed marked female predominance. PBC was more frequent in women aged 50-69 years. However, AIH demonstrated a broader age distribution, affecting individuals from young adulthood to older age. Higher prevalence estimates were observed in multiple northern regions, particularly in the Caribbean region. CONCLUSIONS: This first nationwide administrative assessment of PBC and AIH in Colombia demonstrates marked sex differences and regional variation, highlighting the need to improve diagnostic awareness and strengthen epidemiological surveillance of autoimmune liver diseases in Latin America.