Clinical Utility of the Neutrophil-to-Bilirubin Ratio in the Detection of Disease Activity in Ulcerative Colitis

BACKGROUND: Ulcerative colitis (UC) is a chronic relapsing remitting form of inflammatory bowel disease (IBD). Current disease monitoring includes evaluation of symptoms, fecal calprotectin, and colonoscopy. Due to limited availability of the latter two modalities in China, we sought a readily available, inexpensive, disease monitoring laboratory assessment. We recently identified a novel serological index (the neutrophil-to-bilirubin ratio, NBR) for monitoring disease activity in Crohn’s disease. However, the clinical significance has not been evaluated in UC. Here, we aimed to verify the hypothesis that NBR might be useful in monitoring clinical and endoscopic activity in patients with UC. METHODS: To test our hypothesis, we conducted a single-center, retrospective study including a total of 188 patients with UC and 145 non-IBD controls. NBR was calculated to determine its practical value in monitoring disease activity (including clinical and endoscopic activity). Disease activity of UC was determined by the partial Mayo score and the Mayo endoscopic score (MES) system. RESULTS: NBR was significantly higher in patients with UC than that in controls (12.10, IQR: 9.85–16.69 versus 5.06, IQR: 3.94–6.55; p < 0.001) and showed positive correlations with clinical and endoscopic disease activity in UC. Additionally, NBR was significantly lower in patients with endoscopic mucosal healing (MH) than that in those without endoscopic MH (8.81, IQR: 6.67–11.67 versus 13.51, IQR: 11.04–18.71; p < 0.001). Serial evaluation of NBR in a subset of patients demonstrated that NBR was significantly decreased during the MH stage compared with that during the endoscopically active stage. CONCLUSION: Our study suggests that NBR may be a promising candidate for assessing disease activity in UC, with potential for widespread clinical use and significant clinical implications.