The association between bilirubin concentrations and inflammatory bowel disease: Insights from a systematic review and meta‐analysis

Abstract Background Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), poses a significant challenge to health care systems because of its chronic nature and increasing global prevalence. Effective management of IBD requires accurate diagnostic tools and biomarkers. This systematic review and meta‐analysis aimed to evaluate the relationship between bilirubin concentrations and IBD activity and outcomes. Methods A comprehensive search of electronic databases identified 11 studies that included 2606 subjects with IBD and 3607 healthy controls. Results Bilirubin concentrations were significantly lower in subjects with IBD when compared to controls (SMD = −0.96, 95% CI −1.21 to −0.70; p < .001). Although substantial heterogeneity was observed, sensitivity analysis confirmed the robustness of the results. Publication bias was detected, but subgroup analyses did not significantly alter the results. Meta‐regression showed that age was a significant factor influencing the association between bilirubin concentrations and IBD. Subgroup analyses showed a more pronounced reduction in bilirubin concentrations in subjects with CD than those with UC. Conclusion This study supports the potential utility of bilirubin as a biomarker in IBD, emphasizing the need for further research to validate its clinical significance.