Assessment of the Correlation between Endoscopic Activity and Histological Activity in Ulcerative Colitis Patients

OBJECTIVE: The aim of this study was to assess the concordance between the Rachmilewitz endoscopic activity index (EAI) and the Harpaz histopathological activity scoring system (HSS), which are used for evaluating the disease activity of ulcerative colitis (UC). SUBJECTS AND METHODS: This study included 109 patients with UC. Based on the disease extent, patients were divided into two groups as left-sided colitis and pancolitis. Patients were grouped as inactive, mild, moderate and severe depending on the Rachmilewitz EAI and Harpaz HSS. Kendal's tau and kappa (κ) statistics were used to assess the agreement between endoscopic and histopathological scores. A receiver operating characteristic (ROC) curve was also analyzed to evaluate the sensitivity and specificity of endoscopic scores to predict inactive histopathological disease. RESULTS: In the left-sided colitis group, there were slight and poor agreements in the inactive endoscopic subscores (ESS) with inactive Harpaz HSS (κ: 0.598, p < 0.001) and moderate ESS with moderate Harpaz HSS (κ: 0.236, p = 0.046). There was no agreement between mild ESS and mild Harpaz HSS and between severe ESS and severe Harpaz HSS (κ: 0.071, p = 0.573 and κ: 0.160, p = 0.151, respectively). In the pancolitis group, there was no significant agreement between inactive, mild, moderate and severe ESS and the equivalent Harpaz HSS grades (κ: −0.194, p = 0.187; κ: 0.125, p = 0.397; κ: 0.148, p = 0.175 and κ: 0.174, p = 0.153, respectively). The ROC curve showed that the ESS indicating inactive disease had a low sensitivity to predict histologically inactive disease. CONCLUSION: The concordance between the endoscopic and histopathological indices was poor. Using both scores in the follow-up of patients with UC is necessary for treatment planning.