Evidence have been supporting that histological activity of ulcerative colitis [UC] has relevance for the prediction of clinical outcomes in UC patients, such as clinical relapse. In this study, we aimed to compare two histological indexes – the continuous Geboes score [GS] and the Nancy index [NI] – regarding their definitions of histological remission and response, and to determine the ability of fecal calprotectin [FC] levels to discriminate between these histological statuses according to the NI.
A large cohort of UC patients [N=422] that was previously enrolled in other studies was analyzed.
GS and NI were shown to be strongly correlated [correlation coefficient: 0.882, p < 0.001], indicating high accordance in the classification of patients as having/not having histological remission and response. FC levels moderately correlated with NI regarding these histological statuses [correlation coefficient: 0.481, p < 0.001], moderately predicted the absence of remission defined by NI > 0 [area under the curve (AUC) 0.667 (95% CI 0.609-0.724)], and were good predictors of the absence of histological response defined by NI > 1 [AUC 0.825 (95% CI 0.777-0.872)]. The optimal FC cut-offs determined to predict the NI-defined histological remission and response were 91 μg/g and 106 μg/g, when maximizing the negative predictive value [NPV].
Due to the higher applicability of the NI, this study encourages the systematic use of this histological index to assess histological remission and response in UC patients.

Copyright © 2020 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.