Background: Fecal calprotectin (FC) is a reliable surrogate marker for inflammatory activity in IBD. Providing a patient with an option for self–monitoring of the disease has been proven to empower patients, increase adherence and help cut the costs of health care with increasing amount of IBD patients.
In this study, we validated a symptom index suitable for ulcerative colitis and colonic Crohn's disease. By combining the symptom index with a rapid semi-quantitative FC test, we constructed a new activity index based on the highest AUC:s, using histological remission as a reference. We also evaluated the correlation of the patient-reported influence of the IBD in the daily life, measured with a VAS scale, with the inflammation activity.
Methods: The disease activity of 72 patients with ulcerative colitis or colonic Crohn's disease was determined by endoscopic activity scores (SES-CD/UCEIS). The patients provided stool samples for determination of FC with an ELISA test and a rapid FC test (Prevent ID CalDetect, Preventis, Immunodiagnostics AG, Bensheim, Germany), and filled in a questionnaire about their symptoms during the last week.
Results: The results of the symptom index demonstrated a statistically significant correlation with the FC tests, histological inflammation activity and the VAS scale. The sensitivity and specificity of the new index in distinguishing inactive from active disease were comparable to those of FC. The specificity of the VAS scale in detecting histologically inactive disease was low, and no correlations were found between the VAS scale and FC or the histological inflammation activity.
For the combination index, the highest AUC for the histologically inactive disease was achieved using the following formula:
1.6 (if pIBD-SI is ≥2) + 1 (if CalDetect is 50–200) + 2.4 (if Caldetect is >200)
The sensitivity of the combination index to detect active inflammation was slightly superior to FC test alone.
Conclusions: The new symptom score and the combination index are simple non-invasive means for distinguishing remission or mild inflammation from active inflammation in colonic IBD. With the VAS scale we can pick up patients who need psychosocial support because of the disease burden, even if their IBD is in remission. With these new indices patients are able to monitor their disease activity at home, and contact the outpatient clinic only when needed.
 D'Haens et al. (2012), Fecal calprotectin is a surrogate marker for endoscopic lesions in inflammatory bowel disease, Inflamm Bowel Dis
 Jonefjäll et al. (2013), Characterization of IBS-like symptoms in patients with ulcerative colitis in clinical remission, Neurogastroenterology & Motility
 Puolanne et al. (2016), Rapid faecal tests for detecting disease activity in colonic IBD, Eur J Clin Invest