Autoimmune hepatitis-PBC overlap syndrome: a simplified scoring system may assist in the diagnosis

Primary biliary cirrhosis (PBC) with features consistent with autoimmune hepatitis (AIH) has been described as an overlap syndrome. Recently, a simplified AIH scoring system has been proposed by the International Autoimmune Hepatitis Group (IAIHG), which is based on only four clinical components. We aimed to evaluate the performance of the new simplified AIH scoring system as a diagnostic instrument for PBC-AIH overlap syndrome compared with the revised 1999 IAIHG criteria. Furthermore, we sought to compare the outcome in PBC patients with and without the features of AIH overlap.

Retrospective analysis of PBC patients was carried out. Parameters relevant to the revised criteria were recorded, and outcomes were compared between those with and without features of overlap.

Of 368 patients (318 females) with a definite diagnosis of PBC, 43 (12%) were diagnosed as probable PBC-AIH overlap with the revised criteria and 23 (6%) with the simplified criteria. In both scoring systems the frequency of cirrhosis, portal hypertension, gastrointestinal (GI) bleeding, ascites, and esophageal varices was significantly higher in the overlap group at the time of follow-up. Patients with features of overlap according to the new criteria had more frequent liver-related death and liver transplantation (P=0.0025, log rank test).

The simplified AIH scoring system appears to be more specific in patients with PBC and could assist in clinical assessment. Worse outcome was observed in patients with overlap features, demonstrated as increased liver-related mortality with the new criteria. The new criteria should be able to replace the revised criteria for the diagnosis of PBC-AIH overlap syndrome.