P215 Correlation between small bowel capsule endoscopy and biomarkers in postoperative recurrence in Crohn's Disease. (21st January 2022) - Elosua Gonzalez, A
Abstract: Background: Endoscopic postoperative recurrence (POR) measured by the Rutgeert′s score is a strong predictor of clinical recurrence. Ileocolonoscopy is the gold standard in the diagnosis of POR by recent guidelines and is recommended within the first 6 to 12 months after surgery. After the initial ileocolonoscopy the monitoring is usually based on non-invasive test such as fecal calprotectin (FCP), imaging studies or small bowel capsule endoscopy (SBCE) since symptoms are not reliable of mucosal lesions. Our aim was to evaluate the accuracy of FCP and C-reactive protein (CRP) for detection of endoscopic recurrence measured by SBCE. Methods: We included all patients with known CD with previous ileocolonic resection followed in the Inflammatory Bowel Disease Unit of Hospital Universitario de Navarra from 01/01/2008 to 31/12/2019 in which a SBCE was performed. CRP was considered elevated if >5g/L. To avoid bias from disease activity in colon undetectable by SBCE, only L1 patients were included in this specific analysis. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and diagnostic Odds Ratio (DOR) were calculated. Receiver operating characteristic curve (ROC) and its area under the curve (AUC) were calculated with FCP and CRP. Results: A total of 113 SBCE procedures were performed for evaluation of POR but only 89 were L1 patients. CRP was available for all patients (16.9% elevated) and FCP for 66.3% within 3 months previous to SBCE. Patients with significant POR had a higher mean CRP (4.8 ± 6.6 vs 2.5 ± 5.2, p= 0.017) and FCP (176.3 ± 178 vs 86.3 ± 132, p= 0.04). Diagnostic performance for detecting ≥i2 in neoterminal ileum for CRP was: sensitivity 24.4 %, specificity 89.6%, PPV 66.7%, NPV 58.1%, DOR 2.8. Diagnostic accuracy was obtained for FCP levels of 50 µg/g, 100 µg/g, 150 µg/g and 200µg/g and shown on the table.CRP and FCP had an AUC of 0.7 (95% CI 0.56–0.84) and 0.7 (95% CI 0.56–0.84) respectively. Conclusion: FCP is an accurate surrogate marker of postoperative endoscopic recurrence. The FCP cut-off 100 µg/g appears to have the best overall accuracy.