Alan Bonder, MD, on Extrahepatic Autoimmune Diseases in Patients With Primary Biliary Cholangitis
Primary biliary cholangitis (PBC) is a chronic inflammatory autoimmune disease that will culminate in end-stage biliary cirrhosis if left untreated. Patients with PBC are known to frequently present with other autoimmune diseases, such as Sjögren syndrome, rheumatoid arthritis, and psoriasis.
One of authors of the study report—and our Section Editor for Hepatic Diseases and Disorders—Alan Bonder, MD, from Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, answered our questions about his recent research into extrahepatic autoimmune diseases (EHAIDs) among patients with PBC.
GASTROENTEROLOGY LEARNING NETWORK: What was the primary purpose of this study of EHAIDs in patients with PBC?
ALAN BONDER, MD: The prevalence and clinical significance of EHAIDs had not been evaluated in a large cohort of patients with PBC until this study. We wanted to get better information about the percentage of patients with PBC who also develop EHAIDs.
GLN: You identified 35 different EHAIDs in this population of more than 1500 patients, ranging from Sjögren syndrome to psoriasis. Does the type of EHAID have an impact on how you treat PSC in a particular patient? For example, would certain therapeutic agents for PBC be contraindicated in a patient who presents with rheumatoid arthritis? Or vice versa?
AB: It does not. We will continue the same treatment for PBC with our standard-of-care medication. Currently, none of the medications used for PBC, such as ursodiol, are contraindicated in other autoimmune disorders, but it is important to look for other autoimmune disorders among all patients who have PBC.
GLN: The clinical endpoints for your research were decompensated cirrhosis and hepatocellular carcinoma. The study results showed no difference in event-free survival among patients with and without EHAIDs. But does the presence of an EHAID provide any assistance in risk stratification of patients, to help identify which are most likely to eventually require liver transplantation?
AB: Not really, no. Patients with PBC will be screened for these types of complications once they have clinical, radiological or histological evidence of cirrhosis, so the presence of EHAIDs does not really play a role in stratification.
GLN: Unlike primary sclerosing cholangitis (PSC), PBC is not often associated with inflammatory bowel disease (IBD). Did your research cast any light on why this difference exists between PSC and PBC, in regard to the frequency with which IBD occurs?
AB: For patients with PSC, the rate of underlying IBD has been estimated to be as high as 70%. The risk for IBD among patients with PBC is much lower, but still present—only 2% to 8% of patients with PBC develop IBD. However, patients with PBC have a higher incidence of celiac disease. In one study, the prevalence of celiac disease in patients with PBC was 6%. So this is definitely something that we need to pay attention to when treating patients with PBC.
GLN: What do you think is the most important takeaway from this research project?
AB: I think the most important thing for us to keep in mind is that once a patient has an autoimmune disorder, as clinicians we should always look for clinical, biochemical, and serological evidence to indicate whether the patient has another autoimmune condition. About 25% of patients with one autoimmune disease are likely to develop additional autoimmune disorders, so we have to be on the lookout for that.
Efe C, Murat Torgutalp M, Henriksson I. Extrahepatic autoimmune diseases in primary biliary cholangitis: prevalence and significance for clinical presentation and disease outcome. J Gastroenterol Hepatol. Published online August 13, 2020. https://doi.org/10.1111/jgh.15214