Autoimmune hepatitis (AIH) is a chronic progressive liver disease characterized by circulating autoantibodies and hyperglobulinemia. This study was conducted to identify the features of AIH accompanied by systemic lupus erythematosus (SLE‐AIH) that differ from those of primary AIH (P‐AIH), and to evaluate factors that affect the outcome for SLE‐AIH patients.

From May 1995 to April 2014, clinical data (including liver pathology) from 164 patients with P‐AIH and 23 patients with SLE‐AIH were collected from an electronic database at a tertiary referral center. AIH was diagnosed according to the diagnostic scoring system for AIH (revised in 1999). SLE patients fulfilled at least 4 of the 1997 revised American College of Rheumatology criteria. Progression was defined as occurrence of cirrhosis, hepatocellular carcinoma, liver transplantation, or death from hepatic failure.

The age at the time of AIH diagnosis was lower and initial levels of serum IgG were higher in SLE‐AIH than in P‐AIH patients. Progression was more common in P‐AIH, and hepatocellular carcinoma, liver transplantation, or death occurred only in P‐AIH patients. Among 23 patients with SLE‐AIH, 8 with cirrhosis had higher levels of serum IgG than 15 patients without cirrhosis (mean ± SD 4,077.4 ± 1,641.0 mg/dl and 2,560.7 ± 932.2 mg/dl, respectively; P = 0.017). Moreover, a serum IgG level more than 2‐fold the upper normal limit was associated with a high risk of cirrhosis in SLE‐AIH (odds ratio 11.00 [95% confidence interval 1.420–85.201]; P = 0.026).

Initially high levels of serum IgG are a poor prognostic factor for SLE‐AIH. Additionally, the long‐term outcome for SLE‐AIH might be better than for P‐AIH.