The role of calprotectin in predicting endoscopic post-surgical recurrence in asymptomatic Crohn's disease: a comparison with ultrasound.

BACKGROUND AND OBJECTIVES Faecal calprotectin is predictive of clinical relapse in inflammatory bowel disease and ultrasound is sensitive in detecting its post-surgical recurrence. However, no data regarding the role of calprotectin in predicting post-surgical recurrence in asymptomatic Crohn's disease are available. The aim of this study was to prospectively evaluate the role of calprotectin as a predictive marker for one year post-surgical endoscopic recurrence in comparison with ultrasound in patients with asymptomatic Crohn's disease. MATERIAL AND METHODS We consecutively enlisted 50 patients who had undergone a resection for Crohn's disease. Faecal calprotectin was analysed and ultrasound were performed at the third month, and a colonoscopy after one year. The sensitivity and specificity of these two techniques were evaluated using endoscopic findings as a golden standard. A Receiver Operator Curve (ROC) curve was plotted, in order to identify the best-cut off value for calprotectin. RESULTS 39 out of 50 patients were evaluated by performing a colonoscopy after one year; 19 patients had an endoscopic recurrence after one year. Calprotectin sensitivity and specificity were calculated for 5 different cut-off values; the best cut-off value for calprotectin sensitivity (63%) and specificity (75%) was > 200 mg/L. The US sensitivity and specificity at the third month were 26% and 90% respectively. CONCLUSIONS When performed three months after surgery ultrasound is more specific than calprotectin in predicting endoscopic recurrence. Faecal calprotectin at a dosage > 200 mg/L seems to have a better sensitivity than ultrasound. Values of calprotectin > 200 mg can be an indication to colonoscopy in the group of patients with negative ultrasound in order to detect early recurrence.