S12 Epidemiological Association Between SLE and Autoimmune Cholangiopathies: A National Inpatient Sample-Based Study

Introduction: Systemic lupus erythematosus (SLE) has been increasingly linked to autoimmune liver diseases such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC). Genetic and epidemiological evidence points to a bidirectional relationship between SLE and PBC, along with a heightened risk of SLE in patients with PSC. However, large-scale clinical data validating these associations remain limited. This study investigates the relationship between SLE and PBC/PSC using a national inpatient database. Methods: We conducted a retrospective cohort study using the National Inpatient Sample database from 2018 to 2022. Adult patients (≥18 years) with a diagnosis of SLE, PBC, or PSC were identified using ICD-10 codes. The prevalence of PBC and PSC among patients' hospitalizations with SLE was assessed. Categorical and continuous variables were analyzed using chi-square and t-tests, respectively. Multivariable logistic regression models adjusted for demographics, hospital characteristics, and comorbidities were used to assess associations. Results: A total of 62,445 PBC-related and 29,150 PSC-related adult hospitalizations were identified, with 3.03% and 1.09% of these cases, respectively, also diagnosed with SLE. Demographic differences between cohorts with and without SLE were not statistically significant. Multivariable logistic regression showed a strong association between SLE and both PBC and PSC after adjusting for confounders. The odds of SLE were over fourfold higher in PBC (adjusted odds ratio 4.13; 95% CI, 3.69–4.63; P < 0.001) and more than twofold higher in PSC (adjusted odds ratio 2.23; 95% CI, 1.67–2.98; P < 0.001). Age was positively associated with PBC and inversely with PSC, while female sex increased the odds of PBC and reduced the odds of PSC. Race, income, hospital factors, and comorbidities also influenced disease odds. Conclusion: The findings of this study reveal a significantly higher prevalence of SLE among patients hospitalized with PBC and PSC. Although the retrospective design and use of diagnostic coding may limit data accuracy, these results offer large-scale clinical validation of previously proposed genetic associations and emphasize the importance of proactive screening and multidisciplinary management of hepatobiliary autoimmune comorbidities in patients with SLE.