Serum leucine-rich alpha-2 glycoprotein as a predictive factor of endoscopic remission in Crohn's disease

Background and Aim The usefulness of fecal calprotectin (FC) and serum leucine-rich alpha-2 glycoprotein (LRG) assessing the activity of Crohn's disease (CD) remains to be fully demonstrated in Asia. The present study aimed to elucidate whether FC and LRG could predict endoscopic remission (ER) in Japanese patients with CD. Methods Between October 2018 and July 2021, we prospectively observed treatment courses of CD patients treated with biologic agents. The optimal cutoff values of Crohn's Disease Activity Index (CDAI), serum C-reactive protein (CRP), serum albumin (Alb), FC, and LRG levels for predicting ER at week 52 were calculated using receiver operating characteristic (ROC) curves. We also analyzed the correlations between the achievement of clinical remission (CR) or biomarker remission (BR) at week 12/24/52 and ER at week 52. Results Among 53 patients who completed 52 weeks of observation, 20 (37.7%) achieved ER at week 52. Using the calculated cutoff values, patients who achieved CR (CDAI <= 112) or BR (CRP <= 0.42 mg/dL, Alb >= 3.8 g/dL, FC <= 287 mu g/g, or LRG <= 13.6 mu g/mL) at week 12/24/52 had a higher ER rate at week 52. FC-BR at week 12/24 showed low sensitivity (0.58/0.60) but high specificity (0.78/0.74) for predicting ER; LRG-BR at week 12/24 also showed low sensitivity (0.68/0.74) but high specificity (0.87/0.78). However, FC-BR and LRG-BR at week 52 had improved sensitivity (0.80/0.84) while specificity remained (0.79/0.85). Conclusions From the early phase of biologic treatment, both FC and LRG had high specificity for predicting ER at week 52. LRG showed higher sensitivity than FC.