P167 The variation of faecal calprotectin level within the first months after bowel resection is predictive of endoscopic postoperative recurrence in patients with Crohn’s disease

Abstract Background Early detection of postoperative recurrence (POR) remains a major concern in patients with Crohn’s disease (CD). We aimed to assess the performances of serial faecal calprotectin (Fcal) monitoring within the three first months following ileocolonic resection to predict CD endoscopic POR at 6 months. Methods In this multi-centre prospective study, CD patients who underwent ileocolonic resection were consecutively enrolled. Stools samples were collected at baseline, at 1 month (M1) and M3 to measure Fcal level. The stools samples were collected in the morning the day before the endoscopy to reduce intraindividual variation, and immediately stored at 4°C. Ileocolonoscopy was performed at M6. Endoscopic POR was defined as Rutgeerts’ index ≥ i2b (central reading). Results Overall, 48 patients were included. The main characteristics of these patients are detailed in Table 1. Among them, 18 patients (36%) presented with endoscopic POR (Rutgeerts score ≥ i2b) 6 months after surgery. We did not observe any significant difference between patients with or without early endoscopic POR (M6), respectively, regarding the level of Fcal at baseline (100 [50–190] vs. 166 [89–312] µg/g; p = 0.15), M1 (93 [48–104] vs. 100 [50–180] µg/g; p = 0.44) and M3 (100 [68–328] vs. 99 [50–100] µg/g; p = 0.28). Fcal kinetics during the first 3 months after surgery was significantly different between the patients with or without POR at M6 (p = 0.021). The relative variation (median) between the level of Fcal at baseline and M3 (ΔFcal M3-M0) was significantly higher in patients with endoscopic POR +60% [−47%–+217%] compared with those without POR −38% [−64%–0%] (p = 0.01). ΔFcal M3-M0 > +10% demonstrated the best performances to predict endoscopic POR at M6 (AUC = 0.73, sensitivity = 64.7% [41.1–82.7], specificity = 87.5% [68.0–96.3], negative predictive value = 77.8% [57.5–91.4] and positive predictive value = 78.6% [49.2–95.3]). Conclusions Fcal variation within the first months after ileocolonic resection is an accurate predictor of early endoscopic POR in CD patients.