P-7 EPIDEMIOLOGY OF AUTOIMMUNE HEPATITIS IN LATIN AMERICA: PRELIMINARY RESULTS FROM ALLATIN COHORT

No Autoimmune hepatitis (AIH) is a rare disease characterized by a destructive immune response to hepatocytes in the absence of an identified causative agent. The epidemiology of AIH in Latin America is largely unknown. This study aims to address the epidemiology of AIH in Latin America. This ongoing retrospective, international, multicentric cohort study, sponsored by ALEH, enrolls AIH patients from different countries in Latin America. Data were accrued on 200 patients [Brazil (36.3%), Argentina (22.3%), Chile (21.8%), Cuba (7.3%), Costa Rica (5.2%), Ecuador (5.2%), and Mexico (2.1%)], 85.9% female, with a mean age at AIH diagnosis of 43.8 years. The most common form of disease presentation was chronic asymptomatic elevation of liver enzymes (40.9%), while acute severe hepatitis and fulminant hepatitis were observed in 7.2% and 2.8% of cases, respectively. Cirrhosis was present in 39% of patients at diagnosis. AIH type 1 was diagnosed in 93.7%, type 2 in 1.6%, while 4.8% were seronegative. Overlap with primary biliary cholangitis and primary sclerosing cholangitis was reported in 5.7% and 2.9% of cases, respectively. Most patients were symptomatic (66.8%) at diagnosis, with jaundice (42.4%) and asthenia (28.3%) being the main symptoms. Hashimoto thyroiditis (11.4%) and lupus (4.9%) were the most common extrahepatic autoimmune diseases associated with AIH. Prednisone was prescribed to 86%, azathioprine to 81%, and mycophenolate to 8% of patients as first-line treatments. Complete biochemical response after the first 12 months of treatment was achieved by 66.9% of patients. Mycophenolate (60%) was the preferred option for second-line therapy, which was prescribed to 10.7% of the individuals. Of the patients, 10.5% died, while 1.5% underwent liver transplantation. Hepatocellular carcinoma was diagnosed in 1.1% of patients. Our unprecedented data shed light on AIH epidemiology and management in Latin America.