Concurrent extrahepatic autoimmunity in autoimmune hepatitis: implications for diagnosis, clinical course and long‐term outcomes

Background Concurrent extrahepatic autoimmune disease (CEHAID) associated with autoimmune hepatitis (AIH) have been incorporated into the diagnostic criteria stipulated by the International Autoimmune Hepatitis Group (IAIHG). Large comprehensive cohort data on the extrahepatic autoimmunity in AIH remain scanty. Aim To systematically assess features and clinical impact of CEHAID on AIH. Methods Clinical records of 562 patients with AIH from two tertiary centres in the UK were retrospectively reviewed. Results Prevalence of CEHAID in patients with AIH was 42%. Autoimmune thyroid disease was the commonest CEHAID associated with AIH (101/562, 18%). Autoimmune skin diseases were more prevalent in AIH‐2 than AIH‐1 (21.9% vs 7%, P=.009). Personal history of CEHAID was more commonly found in AIH patients with than without first‐degree family history of CEHAID [48/86 (55.8%) vs 169/446 (37.9%), P=.002]. AIH patients with CEHAID were more often women (85.2% vs 76.1%, P=.008), had higher post‐treatment IAIHG score (22 vs 20, P