Blood Urea Nitrogen to Serum Albumin Ratio Is Associated with MASH and Significant Fibrosis: Report from a Turkish Biopsy-Proven MASLD Cohort

Background/Objectives: The blood urea nitrogen-to-serum albumin ratio (BAR) is a recently established index that has been associated with systemic inflammation. This study aimed to evaluate the association between BAR levels and histopathological findings in patients with biopsy-proven MASLD. Methods: A total of 425 biopsy-proven MASLD patients from the Turkish MASLD Biobank were included in the analysis. Histological assessments were performed according to the SAF/FLIP algorithm. The BAR was calculated as indicated. Results: The median age was 49 [19–71] and54% of the patients were male (n = 229). A total of 204 (48%) and 377 patients (88.7%) had significant fibrosis and metabolic dysfunction-associated steatohepatitis (MASH), respectively. BAR was significantly lower among patients with significant fibrosis [3.11 (0.21–9.41) vs. 3.41 (1.37–11.49), p = 0.002]. The same trend was observed among patients with MASH (3.2 [0.2–11.5] vs. 4.6 [1.9–8.7]), p < 0.001). Also, there is a decline beginning from F0 to F4 fibrosis (p = 0.014). In multivariate analysis, BAR remained an independent predictor after adjustment for confounders (OR 0.813, p = 0.020). BAR showed an AUROC of 0.586 (95% CI: 0.532–0.640) for predicting significant fibrosis. Conclusions: This is the first study to evaluate BAR levels in patients with biopsy-proven MASLD, demonstrating that BAR levels were inversely associated with the presence of significant fibrosis. These findings show an association between declining BAR levels and impaired liver health. However, the results should be interpreted cautiously owing to their suboptimal statistical performance.