Predicting mucosal healing in patients with ulcerative colitis in clinical remission using biomarkers: A single-center prospective pilot study

Treating ulcerative colitis (UC) requires mucosal healing (MH); however, clinical remission does not always involve MH. Fecal calprotectin (FC) is a useful marker to determine MH. Leucine-rich alpha-2 glycoprotein (LRG) and prostaglandin E-major urinary metabolite (PGE-MUM) have similar performance to FC and may also predict MH. No previous studies have provided a detailed comparative analysis of LRG, PGE-MUM, and FC. Herein, we investigated their associations with endoscopic activity and their potentials as predictors of MH. This single-center, prospective, observational study included patients with ulcerative colitis in clinical remission for >3 months (partial Mayo score ≤ 2) who were to undergo colonoscopy between July 2023 and June 2024. Endoscopic remission (ER) was defined as Mayo endoscopic score of 0, while histological remission (HR) was based on the Geboes score. Overall, 46 patients were enrolled, and all underwent colonoscopy; 20 (43%) had ER, and 9 (20%) had HR. The median LRG, PGE-MUM, and FC levels were significantly higher in patients without ER than in those who achieved ER (P < .05). The areas under the receiver operating characteristic curves of LRG, PGE-MUM, and FC for determining ER were 0.686 (95% confidence interval [CI]: 0.530-0.845), 0.695 (95% CI: 0.552-0.872), and 0.788 (95% CI: 0.658-0.919), respectively. The optimal cutoff value obtained from the receiver operating characteristic curve, LRG, PGE-MUM, and FC values for determining ER were 14.2 µg/mL, 30.6 μg/gCr, and 143 mg/kg, respectively. The areas under the receiver operating characteristic curves for LRG + FC and PGE-MUM + FC to determine ER were 0.800 (95% CI: 0.672-0.928) and 0.865 (95% CI: 0.764-0.966), respectively. LRG and PGE-MUM are potential biomarkers for determining ER in clinical remission. Combining LRG and PGE-MUM assessments with FC may improve the accuracy of confirming ER in ulcerative colitis, even during the remission phase.