Abstract: Background & Aims: Growing evidence suggests an increased prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) in the context of immune-mediated inflammatory diseases (IMIDs). We aimed to clinically and mechanistically characterize steatotic liver disease (SLD) in a prospective cohort of patients with IMID compared to controls. Methods: Cross-sectional, case-control study including a subset of patients with IMID. Controls from the general population were age-, sex-, type 2 diabetes-, and BMI-matched at a 1:2 ratio. SLD was established using controlled attenuation parameter. Liver biopsies were obtained when significant liver fibrosis was suspected. Total RNA was extracted from freshly frozen cases and analyzed by RNA-seq. Differential gene expression was performed with limma-voom. Gene set-enrichment analysis was performed using the fgsea R package with a preranked limma t-statistic gene list. Results: A total of 1,456 patients with IMID and 2,945 controls were included. Advanced SLD (liver stiffness measurement 9.7 kPa) (13.46% vs. 3.79%; p <0.001) and advanced MASLD (12.8% vs. 2.8%; p <0.001) prevalence were significantly higher among patients with IMID than controls. In multivariate analysis, concomitant IMID was an independent, and the strongest, predictor of advanced SLD (adjusted odds ratio 3.318; 95% CI 2.225-4.947; p <0.001). Transcriptomic data was obtained in 109 patients and showed 87 significant genes differentially expressed between IMID-MASLD and control-MASLD. IMID-MASLD cases displayed an enriched expression of genes implicated in pro-tumoral activities or the control of the cell cycle concomitant with a negative expression of genes related to metabolism. Conclusions: The prevalence of advanced SLD and MASLD is disproportionately elevated in IMID cohorts. Our findings suggest that IMIDs may catalyze a distinct MASLD pathway, divergent from classical metabolic routes, highlighting the need for tailored clinical management strategies. Impact and implications: The prevalence of steatotic liver disease with advanced fibrosis is increased in patients with immune-mediated inflammatory diseases, independent of classic metabolic risk factors or high-risk alcohol consumption. Transcriptomic analysis revealed a unique gene expression signature associated with cellular activities that are compatible with a liver condition leading to an accelerated and aggressive form of steatotic liver disease. Our findings underscore the importance of heightened screening for advanced liver disease risk across various medical disciplines overseeing patients with immune-mediated inflammatory diseases.
