Prealbumin and Retinol-Binding Protein 4: The Promising Inflammatory Biomarkers for Identifying Endoscopic Remission in Crohn’s Disease

OBJECTIVE: Endoscopic remission is the primary therapeutic target and associated with clinical outcome in Crohn’s disease (CD). Non-invasive and accurate biomarkers are important in monitoring endoscopic remission frequently. Our study aimed at investigating the predictive capacity of prealbumin and retinol-binding protein 4 (RBP4) for identifying endoscopic remission. METHODS: From June 2018 to December 2020, 515 endoscopy procedures (332 in the training cohort and 183 in the validation cohort) were enrolled in this multicentre retrospective cohort study. Blood samples were collected for prealbumin or RBP4 testing with 7 days before the endoscopy. A simple Endoscopic Score for CD (SES-CD) was performed to evaluate endoscopic activity and defined endoscopic remission. The area under receiver operating characteristic curve (AUROC), sensitivity, specificity, positive predictive value and negative predictive value were performed to assess the predictive capacity of the biomarkers. RESULTS: Serum concentration of prealbumin and RBP4 was demonstrated to be higher in patients with endoscopic remission and significantly negatively correlated with SES-CD in the training cohort. The AUROC of prealbumin and specificity of prealbumin and RBP4 were larger than that of C-reactive protein in the training cohort and the validation cohort. The model combining prealbumin and faecal calprotectin had the largest AUROC (0.842 [95% CI: 0.775–0.908]). Furthermore, in both cohorts, prealbumin had a larger AUROC than C-reactive protein for identifying endoscopic remission in patients with anti-tumour necrosis factor therapy. CONCLUSION: Prealbumin and RBP4 were promising biomarkers for identifying endoscopic remission, especially in patients with anti-tumour necrosis factor therapy.