The Modified Mayo Endoscopic Score (MMES): A New Index for the Assessment of Extension and Severity of Endoscopic Activity in Ulcerative Colitis Patients

Background and aims: Current endoscopic activity scores for ulcerative colitis (UC) do not take into account the extent of mucosal inflammation. We have developed a simple endoscopic index for UC that takes into account the severity and distribution of mucosal inflammation. Methods: In this multicentre trial, UC patients undergoing colonoscopy were prospectively enrolled. For the Modified Score (MS), the sum of Mayo Endoscopic Subscores (MESs) for five colon segments (ascending, transverse, descending, sigmoid and rectum) was calculated. The Extended Modified Score (EMS) was obtained by multiplying the MS by the maximal extent of inflammation. The Modified Mayo Endoscopic Score (MMES) was obtained by dividing the EMS by the number of segments with active inflammation. Colon biopsies were obtained from the rectum and sigmoid, as well as from all inflamed segments, by standard methods. Clinical activity was scored according to the Partial Mayo Score (PMS). Biological activity was scored according to C-reactive protein (CRP) and faecal calprotectin (FC) levels. Histological activity was scored according to the Geboes Score (GS). Results: One hundred and seventy-one UC patients (38% female, median age 47 years, median disease duration 13 years) were included. The MMES correlated significantly with the PMS (r = 0.535), CRP (r = 0.238), FC (r = 0.730) and GS (r = 0.615) (all p < 0.001). Median MMES scores were significantly higher in patients with clinical, biological or histological activity (all p = 0.001) Conclusions: The MMES is an easy to use endoscopic index for UC that combines the severity analysis of the MES with disease extent, and correlates very well with clinical, biological and histological disease activity.