While associations are known to exist between primary biliary cholangitis (PBC) and many different types of thyroid disease (TD), a new study shows that the mere presence of thyroid disease does not have any bearing on the hepatic complications or progression of PBC.

“The prevalence of TD in PBC reportedly ranges between 7.24% and 14.4%, the most often encountered thyroid dysfunction being Hashimoto’s thyroiditis,” wrote the study’s authors, led by Annarosa Floreani, MD, of the University of Padua (Italy).

Dr. Floreani and her colleagues prospectively enrolled 376 patients from Padua and 545 patients from Barcelona, all of whom received a PBC diagnosis at some point between 1975 and 2015. Patients were all enrolled from an unnamed database and were followed up for 126.9 months, on average.

Of the 921 total patients enrolled, 150 (16.3%) had TD. The most common TD patients had were Hashimoto’s thyroiditis, which 94 (10.2%) individuals had; Graves’ disease, found in 15 (1.6%) patients; multinodular goiter, which 22 (2.4%) patients had; thyroid cancer, which was found in 7 (0.8%); and “other thyroid conditions,” which affected 12 (1.3%) patients. Patients from Padua had significantly more Graves’ disease and thyroid cancer than those from Barcelona: 11 (15.7%) versus 4 (5.0%) for Graves’ (P = .03), and 6 (8.6%) versus 1 (1.3%) for thyroid cancer (P = .03), respectively. However, no significant differences were found in PBC patients who had TD and those who did not, when it came to comparing the histologic stages at which they were diagnosed with PBC, hepatic decompensation events, occurrence of hepatocellular carcinoma, or liver transplantation rate. Furthermore, TD was not found to affect PBC survival rates, either positively or negatively.

“The results of our study confirm that TDs are often associated with PBC, especially Hashimoto’s thyroiditis, which shares an autoimmune etiology with PBC,” the authors concluded, adding that “More importantly … the clinical characteristics and natural history of PBC were much the same in the two cohorts, as demonstrated by the absence of significant differences regarding histological stage at diagnosis (the only exception being more patients in stage III in the Italian cohort); biochemical data; response to UDCA [ursodeoxycholic acid]; the association with other extrahepatic autoimmune disorders; the occurrence of clinical events; and survival.”

No funding source was reported for this study. Dr. Floreani and her coauthors did not report any financial disclosures relevant to this study.