Comparison of the Nancy Index With Continuous Geboes Score: Histological Remission and Response in Ulcerative Colitis.

Background And Aims: Evidence has 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 faecal calprotectin [FC] levels to discriminate between these histological statuses according to the NI.

Methods: A large cohort of UC patients [N = 422] who were previously enrolled in other studies was analysed.

Results: 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% confidence interval [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 maximising the negative predictive value [NPV].

Conclusions: 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.