Assessment of the usefulness of imaging studies and biomarkers in the activity of Crohn’s disease

Aim
The aim of the study was to determine the suitability of available diagnostic methods, by means of comparison, for predicting disease activity, based on cost efficiency and sensitivity criteria.

Material and methods
In this study, we conducted analyses of 37 patients with Crohn’s disease (CD). CD was graded as “active” or “inactive” by adopting certain cut-off values for every marker. The main assumption was that methods used to grade CD severity do not give false positive results. The authors decided to measure the agreement between the methods by applying Cohen’s κ coefficient.

Results
Endoscopy shows the highest sensitivity, negative predictive value, and accuracy in detecting CD. In the case of both intestines, the sensitivity of endoscopy reached 93.9% and the accuracy 94.6%, while the sensitivity and accuracy of enterography and calprotectin were 51.5% vs. 71,9% and 56.8% vs. 72.2%, respectively. For the large intestine, the sensitivity and accuracy of endoscopy reached 100%. For the small intestine, endoscopy had 55% sensitivity and 75% accuracy, while enterography showed only 66.7% and 81.1%, respectively. The best agreement (77.1%, p = 0.005) was seen between endoscopy and calprotectin for full intestines. However, the value of Cohen’s  suggests that this agreement is moderate. The optimal cut-off value for calprotectin was 43 µg/g, and the ROC curve (AUC = 0.871) was large enough to conclude that calprotectin is a statistically significant (p < 0.001) indicator of CD activity.

Conclusions
Statistically significant compliance was shown only between colonoscopy and faecal calprotectin.