Assessment of bidirectional relationships between systemic lupus erythematosus and anxiety disorder: A two-sample Mendelian randomization study.

Background: Observational studies have demonstrated that there was a significant correlation between systemic lupus erythematosus (SLE) and anxiety disorder, but the causal relationship between them is not so clearly established. This study aims to reveal the potential causal link between SLE and anxiety disorder.

Methods: Summary statistical data of SLE and anxiety disorder were from two large-scale genome-wide association studies (GWAS) of European ancestry, followed by a bidirectional two-sample Mendelian randomization (MR) analysis. The inverse variance-weighted (IVW) method was used as the main method to evaluate causal effects, while MR-Egger, weighted median, simple mode, and weighted mode were supplementary methods. Outliers were excluded by MR-pleiotropy residual sum and outlier (MR-PRESSO). Cochran's Q test, MR-Egger intercept test, and leave-one-out analysis were used to evaluate the stability of the results.

Results: According to the results of IVW, we did not observe that there was a statistically significant causal association between genetically predicted SLE and the risk of anxiety disorder (OR = 1.000, 95%CI = 0.992 to 1.008, =.997). Conversely, there were no causal effects between anxiety disorder and SLE risk (OR = 1.000, 95%CI = 0.992 to 1.008, = .997). A similar result was obtained by supplementing the MR method. In addition, sensitivity analysis indicated high stability of the result.

Conclusion: Bidirectional two-sample MR study does not support the causal relationship between SLE and anxiety disorder.