P306 Faecal calprotectin is highly effective to detect endoscopic ulcerations in Crohn’s disease regardless of disease location

Abstract

As the reliability of fecal calprotectin (Fcal) remains debatable to detect endoscopic ulcerations in patients with isolated ileal Crohn’s disease (CD), we aimed to compare its performance to those observed in patients with colonic or ileocolonic location. Using a prospectively maintained database, we analysed all CD patients with Fcal measurement and ileocolonoscopy performed within one month with no therapeutic intervention during this interval. ROC curves were used to determine the best fecal calprotectin threshold to detect endoscopic ulcerations or lesions taking into account the clinical relevance and usual recommended indices (Youden, Liu and efficiency). Sensitivity, specificity, positive (PPV), and negative predictive values (NPV) were presented with 95% confidence intervals for each estimated threshold. The ROC curves were compared using DeLong et al. method. Sensitivity, specificity, PPV, NPV, and accuracy were compared two by two using test of proportions. Overall, 123 patients with CD were included. The baseline characteristics of the patients are presented in Table 1 according to disease location (40 patients in the L1 group and 83 in the L2-–L3 group). Baseline characteristics of the Crohn’s disease patients enrolled in this study (n = 123). The mean Fcal level was significantly higher in patients with endoscopic ulcerations in the L1 group (p = 0.025) and the L2-L3 group (p < 0.001). Using ROC curves, Fcal >200 µg/g and Fcal >250 µg/g were the best thresholds to detect endoscopic ulcerations in the L1 group (sensitivity = 75.0% [47.6–92.7], specificity = 87.5% [67.6–97.3], PPV = 80.0% [51.9–95.7] and NPV = 84.0% [63.9–95.5] and in the L2–L3 group (sensitivity = 84.1% [69.9–93.4], specificity = 74.4% [57.9–87.0], PPV = 78.7% [64.3–89.3] and NPV = 80.6% [64.0–91.8]), respectively. We compared the AUC between L1 and L2–L3 groups and we did not show any difference (0.89 vs. 0.84, respectively, p = 0.46). We also compared two-by-two sensitivity, specificity, PPV, NPV, and accuracy and we did not observe any significant difference (Table 2). Performance of fecal calprotectin to detect endoscopic ulcerations according to Crohn’s disease location (ileal vs. colonic or ileocolonic). Fcal is highly effective to detect endoscopic ulcerations regardless of CD location, but requires a lower cut-off value in patients with pure ileal involvement.