There is evidence of overlap between autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC), two autoimmune hepatobiliary diseases. This retrospective analysis aimed to investigate extra-hepatic auto-immune diseases and compare outcomes of hospitalized patients with AIH-PBC overlap with AIH and PBC. We hypothesize that there are differences in rates of major adverse liver outcomes (MALO’s) when comparing these groups.

We conducted a retrospective cohort study using National Inpatient Sample 2016-2020. Patients with AIH, PBC and AIH-PBC were identified using respective ICD-10 codes. We performed weighted logistic and linear regression for predicting complications of cirrhosis, hospitalization outcomes, among AIH-PBC overlap cases when compared separately to AIH and PBC only populations as controls.

A total of 2,454 AIH, 1,464 PBC, and 276 AIH-PBC overlap patients were identified, corresponding to weighted totals of 12,270, 7,320 and 1,380 patients, respectively. On multivariate analysis, we found that patients with AIH-PBC are more likely to have ascites (OR 3.03; p<0.001) and portal hypertension (OR 3.75; p < 0.001) compared to AIH; whereas no significant difference was found out compared to PBC. There was no difference in the mortality and liver transplant needs in AIH-PBC overlap group. Overall higher rheumatological disease was present in the AIH-PBC overlap patients compared to AIH (26.45% vs 8.96%, p=<0.001) and PBC (26.45% vs 9.08%, p=<0.001). Specifically, AIH-PBC patients had higher prevalence of Sjogren’s syndrome (p<0.001), SLE (p < 0.001), and systemic sclerosis (p<0.001).

AIH-PBC Overlap syndrome is associated with increased rates of certain cirrhotic complications when compared to patients with AIH only. They do not differ in terms of clinical outcomes such as mortality when adjusted for demographics and comorbidities. Patients with AIH-PBC had a higher prevalence of rheumatological disorders; especially Sjogren’s, SLE, and systemic sclerosis.