Background While there have been some case reports documenting concurrent cases of inflammatory bowel disease (IBD) and systemic lupus erythematosus (SLE), there is not a well-established direct correlation between IBD and SLE. The objective of the present study is to utilize a large national database to investigate the association between the prevalence of IBD and SLE.

Methods Data were obtained from the National Inpatient Sample (NIS) database for the year 2019. Patients aged 18 years and above with diagnoses of UC or CD with concurrent SLE were identified as UC-SLE and CD-SLE groups, respectively. The control groups were randomly selected from the list of NIS Database, excluding patients with UC or CD, and propensity-matched to UC or CD cases regarding sex and age, and were identified as non-UC SLE and non-CD SLE groups, respectively. A logistic regression model was used to estimate the association between SLE and either UC or CD in a multivariate analysis.

Results The study included 24925 UC patients and 42091 CD patients, with 124625 and 203135 age- and sex-propensity-matched controls, respectively (IDDF2024-ABS-0452 Table 1a, IDDF2024-ABS-0452 Table 1b). Overall, the proportions of patients with SLE among UC and CD patients were 0.75% and 1.14%, respectively. In the univariate analysis, UC was found not to be associated with SLE (OR 1.09, 95%CI 0.93-1.28, P=0.277) (IDDF2024-ABS-0452 Table 2), while CD was associated with SLE (OR 1.17, 95%CI 1.05-1.29, P=0.003). Also, in a multivariate logistic regression model, CD was found to be independently correlated with SLE (OR 1.21, 95%CI 1.09-1.34, P<0.001) (IDDF2024-ABS-0452 Table 3).

Conclusions Our study showed that CD, not UC, is associated with a higher risk of SLE. This finding highlights the importance of monitoring SLE in patients with CD.