Background: For closer follow up in the postoperative (postop) setting there is a tendency to use fecal calprotectin (FC) rather than colonoscopy in resected Crohn's Disease (CD) patients. The aim of the study was to find out whether there was a significant change between pre and post-procedure FC results, which might influence our clinical practice of stool sampling time.
Methods: For this purpose we prospectively gathered the data of CD patients who were referred to our endoscopy unit in the postop setting. Demographic data like age, age at diagnosis, and operation, sex, disease duration, postop follow up time, smoking status and procedure related factors like insertion-withdrawal time and total duration, Rutgeerts score, pre and post-procedure FC levels were all noted. All patients gave a stool sample 24 hours before and after colonoscopy and all of them had their bowel prepared with the same regimen using PEG. Biopsies were taken in none of the procedures as all of the patients had a firm diagnosis of CD and as no additional lesions were noted. FC was determined via ELISA.
Results: A total of 40 ileocecal resected CD patients (20F/20M)) were included, their mean age being 42.95±12.4 years, disease duration 143.63±83.94 mo. and postop. follow up time 80.9±70.8 mo. The median pre and post procedure FC levels were 144 μg/ml and 113 μg/ml disclosing no significant difference (Fig. 1) and no relation with colonoscopy duration. Seventeen of 40 patients (42%) had endoscopic relapse, and when relapses and non-relapses were analyzed separately the difference between pre- and post-colonoscopy FC levels remained insignificant. Of note was that four of 23 patients (17%) in remission and four of 17 patients with relapse (24%) had changing FC results from negative to positive or vice versa after colonoscopy. In the whole group, when FC cut-off was 50 μg/g 8 of 40 patients (20%) either changed to positive (6/8) or to negative (2/8) after the colonoscopy. When cut off was 100 μg/g nine of 40 (22%) patients' FC changed either to positive (4/40) or to negative (5/40) after the procedure.
Conclusions: The present study shows that pre and post-colonoscopy FC levels are not significantly different. However, one fifth of patients with alternating results using different cut-offs may suggest that it would be more appropriate not to collect stool samples immediately after colonoscopy for FC determination.