Fecal calprotectin measurement is a marker of short-term clinical outcome and presence of mucosal healing in patients with inflammatory bowel disease

AIM To evaluate the utility of fecal calprotectin (FC) in predicting relapse and endoscopic activity during follow-up in an inflammatory bowel disease (IBD) cohort. METHODS All FC measurements that were obtained during a 3-year period from patients with inflammatory bowel disease in clinical remission were identified. Data regarding the short-term (6 mo) course of the disease were extracted from the medical files. Exclusion criteria were defined as: (1) An established flare of the disease at the time of FC measurement, (2) Loss to follow up within 6 mo from baseline FC measurement, and, (3) Insufficient data on file. Statistical analysis was performed to evaluate whether baseline FC measurement could predict the short term clinical relapse and/or the presence of mucosal healing. RESULTS We included 149 [Crohn's disease (CD) = 113, Ulcerative colitis (UC) = 36, male = 77] IBD patients in our study. Within the determined 6-month period post-FC measurement, 47 (31.5%) had a disease flare. Among 76 patients who underwent endoscopy, 39 (51.3%) had mucosal healing. Baseline FC concentrations were significantly higher in those who had clinical relapse compared to those who remained in remission during follow up (481.0 mu g/g, 286.0-600.0 vs 89.0, 36.0-180.8, P < 0.001). The significant predictive value of baseline median with IQR FC for clinical relapse was confirmed by multivariate Cox analysis [HR for 100 mu g/g: 1.75 (95% CI: 1.28-2.39), P = 0.001]. Furthermore, lower FC baseline values significantly correlated to the presence of mucosal healing in endoscopy (69.0 mu g/g, 30.0-128.0 vs 481.0, 278.0-600.0, in those with mucosal inflammation, median with IQR, P < 0.001). We were able to extract cut-off values for FC concentration with a high sensitivity and specificity for predicting clinical relapse (261 mu g/g with AUC = 0.901, sensitivity 87.2%, specificity 85.3%, P < 0.001) or mucosal healing (174 mu g/g with AUC = 0.956, sensitivity 91.9%, specificity 87.2%, P < 0.001). FC was better than CRP in predicting either outcome; nevertheless, having a pathological CRP (> 5 mg/L) in addition to the cutoffs for FC, significantly enhanced the specificity for predicting clinical relapse (95.1% from 85.3%) or endoscopic activity (100% from 87.2%). CONCLUSION Serial FC measurements may be useful in monitoring IBD patients in remission, as FC appears to be a reliable predictor of short-term relapse and endoscopic activity.