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P221 Crohn’s disease activity evaluation based on imaging studies and biomarkers

G. Piotrowicz*1, J. Kowerzanow2, M. Kaszubowski3, E. Szurowska4, G. Rydzewska5

1Self-Dependet Health Care Unit of Ministry of Interior, Gastroenterology, Gdansk, Poland, 2Self-Dependent Health Care Unit of Ministry of Interior, Gastroenterology, Gdansk, Poland, 3Technical University of Gdansk, Economy, Gdansk, Poland, 4Medical University of Gdansk, Radiology, Gdansk, Poland, 5Central Clinical Hospital of the Ministry of Interior of Warsaw, Gastroenterology, Warsaw, Poland

Background

Crohn’s disease (CD) is a chronic condition with variable course.1 Available grading systems include clinical assessment using CDAI scale, imaging studies, and biomarkers.2 The aim of this study is to determine the suitability of available diagnostic methods, by means of comparison, for predicting disease activity, based on cost efficiency and sensitivity criteria.

Methods

In this study, we conducted analyses of 19 patients, with CD. CD was graded as ‘active’ or ‘inactive’ by adopting certain cut-points for every marker. The main assumption of presented analyses was that methods of CD severity grading (endoscopy, SES-CD scale; MRI enterography; DWI ADC; and calprotectin) do not give false positive results. As well, none of these methods was considered a reference method. Authors also decided to measure the agreement between the methods by Cohen’s kappa coefficient and compare them with the CDAI method.

Results

Summary of analysis is presented in Table 1. Endoscopy provides the highest sensitivity, NPV and accuracy in detection of CD activity overall, and in each intestine separately. In case of both intestines, sensitivity of endoscopy reached 93.7% and accuracy 94.7%, as well as enterography with sensitivity 37.5% (accuracy 47.4%), and calprotectin with sensitivity 60.0% (accuracy 64.7%). For the large intestine, endoscopy, sensitivity and accuracy reached 100%, which means there were no cases when enterography detected activity of disease and endoscopy did not. For the small intestine, endoscopy had 70% sensitivity and 84.2% accuracy, whereas the enterography, respectively, only 50% and 73.7%. The best agreement (70.6%) from all pairs of methods and the only 1 that turned out to be statistically important (p = 0,043) was between endoscopy and calprotectin for both intestines. However, value of Cohen’s kappa suggests that this compatibility is rather moderate. The optimal cut-off point for calprotectin level came in at 43 for both techniques (tangent and Youdens indexes).

Table 1 Sensitivity, NPV, and accuracy for presented Methods

MethodSensitivity fraction (ratio)NPV fraction (ratio)Accuracy fraction (ratio)
Endoscopy93.7% (15/16)75% (3/4)94.7% (18/19)
Enterography37.5% (6/16)23.1% (3/13)47.4% (9/19)
Calprotectin60.0% (9/15)25% (2/8)64.7% (11/17)
Endoscopy (small intestine)70% (7/10)75% (9/12)84.2% (16/19)
Enterography (small intestine)50% (5/10)64,3% (9/14)73,7% (14/19)
Endoscopy (large intestine)100% (13/13)100% (6/6)100% (19/19)
Enterography (large intestine)23.1% (3/13)37.5% (6/16)47.4% (9/19)

Conclusion

Comparison of diagnostic methods between each other in the study population showed that the only compatible methods were endoscopy and calprotectin level. This result suggests that activity evaluation based on faecal calprotectin can be used to monitor the course of disease and to optimise the therapy. The presented analysis is a preliminary report, as the study is ongoing.

References

[1] Kaser A, Zeissig S, Blumberg RS. Inflammatory bowel diseases. Annu Rev Immunol 2010;28:573–621.

[2] Rogler G, Aldeguer X, Kruis K, et al. Concept for a rapid point-of-care calprotectin diagnostic test for diagnosis and disease activity monitoring in patient with inflammatory bowel diseases: expert clinical opinion. J Crohn’s Colitis 2013;21(6):360–66.