Reliability of the Endoscopic Ultrasound Ulcerative Colitis (EUS-UC) Score for Assessment of Inflammation in Patients With Ulcerative Colitis

Background and study aims: Endoscopic ultrasound (EUS) may be a useful modality for disease assessment and risk stratification in ulcerative colitis. We assessed the reliability of a newly developed EUS index of inflammation called the EUS-Ulcerative Colitis (EUS-UC) score.

Patients and methods: The EUS-UC score components include total wall thickness, hyperemia, and depth of inflammation (DOI). Three blinded expert endosonographers assessed EUS videos of 58 patients with UC in triplicate. Intra- and inter-rater reliability of the hyperemia and DOI component scores were estimated using intra-class correlation coefficients (ICCs). Total wall thickness reliability estimates could not be assessed in this study. The ICCs were compared to the original indices from which they were derived.

Results: For hyperemia, the inter-class ICC was “moderate” at 0.556 (95 % CI = 0.434-0.651) and the intra class ICC was “almost perfect” at 0.884 (95 % CI = 0.835-0.920). The newly defined hyperemia score performed better than the original index from which is was derived. The DOI inter-class ICC was “fair” at 0.335 (95 % CI = 0.201-0.464), and the intra-class ICC was “substantial” at 0.732 (95 % CI = 0.642-0.802). The DOI reliability estimates were similar to the original index from which it was derived.

Conclusions: The hyperemia component of the EUS-UC score performed significantly better than the original index from which it was derived, but the reliability of the DOI component was suboptimal. Intra-class correlation was excellent for both components. The EUS-UC score is a promising instrument for assessment of UC and further validation is required.