Causal relationship between primary sclerosing cholangitis and systemic lupus erythematosus: a bidirectional Mendelian randomization study.

ABSTRACT

BACKGROUND: Observational studies have found a link between two autoimmune diseases, namely, primary sclerosing cholangitis (PSC) and systemic lupus erythematosus (SLE). However, the relationship remains unclear. METHODS: Bidirectional Mendelian randomization (MR) analysis and statistical methods, including inverse variance weighting, weighted median, and MR-Egger tests, were performed using data from genome-wide association studies to detect a causal relationship between PSC and SLE. Sensitivity analyses were subsequently performed to assess the robustness of the results. Univariate MR methods were also investigated. RESULTS: Results of MR analysis suggested that PSC was associated with an increased risk for SLE (odds ratio 1.33, 95% confidence interval 1.10-1.61, P=0.0039) However, SLE had no significant causal relationship with PSC. CONCLUSION: Results of MR analysis revealed that patients with PSC were at an increased risk for SLE, which provides new insights into the relationship between these two autoimmune diseases.