Fecal Calprotectin More Accurately Predicts Endoscopic Remission of Crohn's Disease than Serological Biomarkers Evaluated Using Balloon-assisted Enteroscopy

Background: Fecal calprotectin (FC) has emerged as a reliable surrogate marker of endoscopic remission in Crohn's disease (CD), which has been mainly evaluated using ileocolonoscopy. We conducted this study to clarify the predictability of FC level for predicting endoscopic remission using balloon-assisted enteroscopy (BAE) findings in patients with CD and compare with that of conventional serological biomarkers. Methods: Patients with CD scheduled to undergo BAE were prospectively enrolled, and fecal and blood samples collected before the procedures. We used a modified simple endoscopic score for CD, in which the parameter "presence of narrowing" was removed from conventional simple endoscopic score for CD. Endoscopic remission was defined as modified simple endoscopic score for CD 0 to 2. Results: Seventy BAE procedures were performed in 53 patients with CD and evaluated. The area under the curve in receiver operating characteristic curve analysis of FC to predict endoscopic remission was 0.93, with an optimal cut-off value of 252.9 mg/g, and 96% sensitivity and 83% specificity, which was higher than that for C-reactive protein, albumin, white blood cell count, and platelet count (0.76, 0.66, 0.39, and 0.65, respectively). The area under the curve of FC for predicting endoscopic remission was high in patients with ileal and ileocolonic disease location (0.86 and 0.96, cut-off values 204.2 and 253.7 mg/g, respectively), and also higher than the area under the curve values of serological markers. Conclusions: BAE findings showed that FC was more accurate for predicting endoscopic remission in CD than C-reactive protein, albumin, white blood cell count, and platelet count. Even in small-bowel CD, FC may be a more reliable surrogate marker of endoscopic remission than serological biomarkers.