Two validated scoring systems now exist, the UCEIS and UCCIS [17, 18]. Both have been shown to have good inter and intra-observer agreement, and the scores account for ≥80% of the variability seen in visual analogue scores. Neither score has yet created a formal definition of endoscopic remission, although an international group of IBD specialists favour the UCEIS and a score of 0/8 [19]. ECCO highlight these scores in recent guidelines [12]. It seems likely both academically and clinically that validated scores will in time replace non-validated ones. The responsiveness of the UCEIS appears to be an advantage over the Mayo Clinic endoscopy sub-score, especially for early-phase clinical trials [20]. This is partly because of the 9-point range in the UCEIS in contrast to the 4-point range in the Mayo Clinic sub-score, but also because the UCEIS does not allow overlapping items for each level. The Food and Drug Administration (FDA) and European Medicines Agency (EMA) in 2015 started taking an active interest in scoring systems and outcome measures in clinical trials for ulcerative colitis, especially with regard to the application of central reading [21].

UCEIS is a straightforward 0–8 point score developed for flexible sigmoidoscopy, scoring the worst affected area. It went through four phases of development and validation, using different cohorts of investigators and videos ranging from normality to acute severe colitis just before colectomy [17]. It should be noted that the first published paper used a range of 3–11 for the score [22], although this was later changed for convenience to 0–8. The UCEIS was developed with anchor points assessed for reproducibility between observers, and interestingly has dropped friability and granularity, both of which were difficult to define reproducibly. Three factors are scored; vascular pattern, bleeding, and erosions and ulcers (Table 29.1). The score is the simple sum of the level for each of the three variables, which makes it simple to use and to remember, although appropriate training is still needed. The scale is reproducible and responsive, and has been validated between international Western experts and community-based gastroenterologists, and is undergoing validation in Asia through the Asian Organisation of Crohn’s and Colitis (AOCC). Higher scores have been shown to correlate with worse clinical outcomes [23]; other, longer-term outcomes in relation to the UCEIS are under study, as well as its relationship to histopathology and impact of clinical details on scoring [24]. A UCEIS training tool has been developed (www.​ecco-ibd.​eu).

The UCCIS was based on the initial development of the UCEIS, but scores the entire colon in each of five colonic segments for vascular pattern, granularity, ulceration, and bleeding/friability. These scores are then each multiplied by a factor and added together to give a whole colon score from 0 to a maximum of 162 [18]. It is validated and correlated clinically with C reactive protein, albumin and haemoglobin. It offers the advantage of an assessment of whole-colon inflammatory burden, but is more cumbersome and requires full colonoscopy and a calculation to complete the score.