Comparative efficiency of leucine-rich alpha-2 glycoprotein and fecal calprotectin to assess endoscopic activity in Crohn’s disease: a prospective observational study

Abstract Background Endoscopic healing is a key therapeutic target for Crohn’s disease (CD). However, endoscopy is invasive, and simple, non-invasive biomarkers are needed to assess endoscopic healing. Although leucine-rich alpha-2 glycoprotein (LRG) and fecal calprotectin (FC) are indicators of inflammatory bowel disease activity, few studies have directly compared them for endoscopic disease activity in CD. We aimed to compare the ability of these markers to assess endoscopic remission in CD. Methods From October 2022 to December 2023, 100 patients with CD at Nagoya University Hospital were prospectively and consecutively enrolled. Endoscopic activity was assessed using the applied simple endoscopic score for Crohn’s disease (aSES-CD), incorporating small bowel lesions. The primary endpoint was the sensitivity of LRG and FC in endoscopic remission (aSES-CD ≤ 3), which was tested using McNemar’s exact test. Logistic regression analysis was used to identify factors associated with endoscopic remission. Results Overall, 84 patients were analyzed (79.8% male; median age 49.5 years). The receiver operating characteristic curve analysis yielded sensitivity/specificity values of 85.9%/90.0% for LRG and 70.3%/85.0% for FC, using cutoff values of 11 µg/mL (LRG) and 100 µg/g (FC) for endoscopic remission. Based on these values, a comparison of sensitivities between LRG and FC showed that LRG had significantly higher sensitivity (P = .013). In multivariate analysis, only LRG was an independent factor for endoscopic remission (odds ratio 3.016; 95% CI, 1.506-6.037). Conclusions Compared with FC, LRG shows a higher sensitivity for assessing endoscopic remission. LRG may serve as a useful biomarker for endoscopic activity in CD.