Faecal Myeloperoxidase as a Biomarker of Endoscopic Activity in Inflammatory Bowel Disease

BACKGROUND AND AIMS: Inflammatory bowel disease IBD, consisting of Crohn's disease CD and ulcerative colitis UC, is a relapsing-remitting illness. Treat-to-target IBD management strategies require monitoring of gastrointestinal inflammation. This study aimed to investigate faecal myeloperoxidase fMPO, a neutrophil granule enzyme, as a biomarker of IBD activity. METHODS: Prospectively recruited participants with IBD, undergoing ileocolonoscopy for disease assessment, provided biological samples and completed symptom questionnaires prior to endoscopy. fMPO, C-reactive protein CRP, and faecal calprotectin fCal were compared with validated endoscopic indices simple endoscopic score for CD and UC endoscopic index of severity. Receiver operating characteristic ROC curves assessed the performance of fMPO, CRP, and fCal in predicting endoscopic disease activity. Baseline biomarkers were used to predict a composite endpoint of complicated disease at 12 months need for escalation of biologic/immunomodulator due to relapse, steroid use, IBD-related hospitalisation, and surgery. RESULTS: A total of 172 participants were recruited 91 female, 100 with CD. fMPO was significantly correlated with endoscopic activity in both CD r = 0.53, p 26 µg/g were significantly more likely to reach the composite outcome at 12 months (hazard ratio [HR 3.71, 95% confidence interval CI 2.07-6.64, p < 0.01). CONCLUSIONS: Faecal myeloperoxidase is an accurate biomarker of endoscopic activity in IBD and predicted a more complicated IBD course during follow-up.