Findings from a Mendelian randomization (MR) study have suggested a causal relationship between primary biliary cholangitis (PBC) and inflammatory bowel disease (IBD), underscoring the need for proactive prevention of PBC among individuals with IBD—particularly those with Crohn’s disease (CD).
Results of the current MR analysis were recently published in Gastroenterology Report.
Although a number of studies have shown that IBD may be associated with an elevated risk for PBC, a causal link between the two disorders remains to be elucidated. Exploring the relationship between the two conditions will help provide an enhanced understanding of their pathogenesis, thus improving management and treatment approaches for individuals with both of these diseases.
Published genome-wide association studies (GWASs) were used to collect genetic variant data from patients with PBC and IBD. The data regarding IBD were divided further into a discovery cohort and a validation cohort, based on the data source involved. A two-sample MR analysis was conducted that utilized the following methods to verify the causal relationship between IBD and PBC:
- Inverse variance weighting (IVW), which was the major focus
- MR-Egger
- Weighted median (WM)
- MR robust adjusted profile score (MR-RAPS)
- Maximum likelihood (ML)
A series of sensitivity analyses were performed as well, to confirm the reliability of the results.
Read more about PBC signs and symptoms
Results of the study revealed that in the discovery dataset, the IVW analysis showed a statistically significant association between IBD and PBC (odds ratio [OR], 1.114; P =.001). Additionally, the MR-RAPS analysis and the ML technique demonstrated results that were consistent with those derived from the IVW method (OR, 1.130; P =.007 and OR, 1.115; P =.011, respectively).
In the validation dataset, there were consistent findings reported with respect to the causal relationship between IBD and PBC via use of the IVW, MR-RAPS, and ML evaluations, with all three techniques recognizing IBD as being a risk factor for the development of PBC.
Based on the IVW method, CD was the most obvious IBD subtype linked to a statistically significant elevated risk for the development of PBC in both the discovery cohort and the validation cohort (OR, 1.068; P =.049 and OR, 1.082; P =.019, respectively).
Results of “[t]his study revealed that there is a close causal relationship between IBD and PBC, [in which] IBD can increase the incidence of PBC,” the authors explained. “It is necessary to identify and prevent the occurrence of PBC in patients with IBD, especially those with CD.”
