Systemic lupus erythematosus (SLE) is a chronic, autoimmune disease that has a wide variety of physical manifestations, including neuropsychiatric features. Bipolar disorder (BD) is a chronic, episodic illness, that may present as depression or as mania. The objective of this study was to investigate the association between SLE and BD using big data analysis methods.

Patients with SLE were compared with age- and sex-matched controls regarding the prevalence of BD in a cross-sectional study. Chi-square and t-tests were used for univariate analysis and a logistic regression model was used for multivariate analysis, adjusting for confounders. The study was performed utilizing the chronic disease registry of Clalit Health Services medical database.

The study included 5018 SLE patients and 25,090 matched controls. BD was found in a higher prevalence among SLE patients compared to controls (0.62% vs. 0.26%, respectively, P<0.001). BD patients had a greater prevalence of smokers compared to non-BD patients (62.5% vs 23.5%, respectively, P<0.001). In a multivariate analysis, smoking and SLE were both found to be significantly associated with BD.

SLE was found to be independently associated with BD. These findings may imply that an autoimmune process affecting the central nervous system among SLE patients facilitates the expression of concomitant BD.