Correlation Between the Nancy Histopathology Index and Markers of Disease Activity in Pediatric Ulcerative Colitis

The Nancy Histological Index (NHI) was developed to assess histological disease activity in adult ulcerative colitis (UC) patients. However, data in pediatrics is limited. Our aim was to determine whether the NHI correlates with different indices of disease activity in pediatric UC patients. We retrospectively reviewed the NHI in rectal biopsies from 61 pediatric UC patients (median age 14.3 years), of whom 34 (55.7%) were newly diagnosed. The median Pediatric Ulcerative Colitis Activity Index (PUCAI) score among participants was 30 (interquartile range 5-55). Most patients exhibited an NHI of 3 (41/61, 67.2%) or 4 (8/61, 13.1%), reflecting moderate-severe histologic inflammation. A moderate positive correlation was identified between the NHI and PUCAI, fecal calprotectin, and Mayo endoscopic scores ( r = 0.60, 0.54, and 0.56 respectively, P ≤ 0.001), but not with CRP or albumin. These results indicate that the NHI has a modest correlation with clinical, laboratory and endoscopic indices of disease activity in pediatric UC patients.