P112 CORRELATION OF FECAL CALPROTECTIN TO COLONOSCOPIC FINDINGS FOR DETECTION OF RECURRENCE OF CROHN’S DISEASE IN THE POST-OPERATIVE SETTING AT A SINGLE ACADEMIC CENTER

Introduction Patients with Crohn’s disease (CD) who undergo a first surgery are at higher risk of having a subsequent surgery in light of recurrence of disease. Significant evidence suggests that a postoperative colonoscopy evaluating recurrence at the anastomosis using the Rugeerts score (RS) can predict risk of repeat surgery. Given the invasive nature of colonoscopy, there has been increasing interest in using noninvasive biomarkers to predict disease recurrence. Studies have shown variability in the operating characteristics of the fecal calprotectin (FC) assay with sensitivities and specificities for detecting recurrence ranging widely from 48–95 and 58–79%, respectively. A recent meta-analysis demonstrated a pooled sensitivity of 70% when using an optimal FC cut-off of 150 ug/g. We sought to delineate how FC correlates with RS at our institution and to identify a cutoff for significant recurrence. Methods We performed a retrospective review of adult patients with CD who underwent ileocecectomy followed by a colonoscopy within 18 months of surgery, with the additional inclusion of FC testing within 2 weeks of the colonoscopy. Patients were identified at our institution via ICD 9 and 10 codes and the electronic medical record. The primary outcome of interest was a comparison of mean FC for those without endoscopic recurrence (defined as RS i0-i1) to those with significant endoscopic recurrence (defined as RS i2-i4). Other variables assessed included gender, disease location and phenotype, and extent of surgery (Table 1). Results A total of 12 patients met the inclusion criteria. 7 patients (58.3%) were female. Age at time of surgery ranged from 21 to 73 years (mean 37.9). Only 1 patient (8.3%) had a nonstricturing, nonpenetrating phenotype. After surgery, 11 patients were on biologic or combination therapy and 1 patient was not on any medical therapy. 5 patients (42%) demonstrated endoscopic recurrence by RS with mean FC of 883.7 ug/g, as compared to mean FC of 83.6 ug/g for those without recurrence. There was a positive correlation between FC and RS with a Spearman’s rank correlation coefficient of 0.86 (p = 0.0004). Conclusions Our results demonstrate a strong correlation between FC and RS. Using a cutoff for FC of 150 ug/g, we demonstrate sensitivity and specificity of 100%. This further supports the possibility of using FC as a surrogate to possibly defer colonoscopy in those post-operative CD patients with low FC. Study limitations include the retrospective nature and small sample size, recognizing that in years past FC was not as readily available or used in this setting. Future considerations include larger, prospective studies looking at FC and other noninvasive biomarkers in this post-operative setting.