Table 1

Comparison of strengths and limitations of commonly used endoscopic scores

Score		Endoscopic activity reporting	Responsiveness to treatments	Prognostic value	Central reading
eMS	Pros	Gross classification of the gestalt of inflammation. Present standard for Drug Agencies (FDA, EMA).	Development focused at responsiveness. Extensively used over past 20 years in trials.	Limited data for a prognostic role in the literature.	Algorithms for central reading. Categorical score leads to easier algorithms for adjudication. Widely used over past 5 years.
eMS	Cons	Final score defined by worst lesion. Lacks precision for global burden of severity and extent of lesions. Lack of face validity Endoscopic features only post hoc defined. Limited spectrum at lower and higher spectrum of activity.	Lack of ability to highlight segmental healing. Lack of responsiveness due to limited range.	Not developed with prognostic intent.	Limited interobserver agreement. Inconsistencies between readers if insufficient washing of the mucosa. Data on impact of reader paradigms on eMS-based endpoints is missing.
UCEIS	Pros	Extensive characterisation and validation of elemental endoscopic lesions focused at agreement.	Better range than eMS.		Already used in some trials.
UCEIS	Cons	Lacks precision for global burden of severity and extent of lesions.	Lack of ability to highlight segmental healing. Limited use in clinical trials. Development not focused at responsiveness.	Not developed with prognostic intent.	Agreement and adjudication more complex for more granular scores as compared with categorical scores. Modest agreement on some lesions (eg, bleeding).
Rutgeerts	Pros	Clear-cut description of elemental lesions.		Development focused on prognosis. Prognostic value has been reproduced.	Central reading easy to implement Algorithms for eMS easily exportable to Rutgeerts’ score.
Rutgeerts	Cons	Not an activity measure. Does not evaluate endoscopic activity outside of the anastomotic site.	No responsiveness evaluation.	Developed for end-to-end anastomoses, never validated for side-to-side anastomoses. Limited interobserver agreement.	Limited interobserver agreement. No data on impact of read paradigm on outcome.
CDEIS	Pros	Developed and validated in order to precisely report disease activity.	Shown in few trials, even if not explicitly developed for responsiveness.		Used in clinical trials. Excellent inter-rater reliability.
CDEIS	Cons	Complexity. Exact weight of each variable to be better clarified. Unvalidated thresholds for remission and response. The definition of remission does not exclude the presence of ulcers.	Not developed with focus on responsiveness.	Limited prognostic value of the sum score.	Agreement and adjudication more complex for continuous scores as compared with categorical scores. Not developed for postoperative anatomy.
SES-CD	Pros	Developed and validated in order to precisely report disease activity. Possibility to easily exclude a given variable. Segmental and ulcer subscores can be calculated.	Shown in several trials, even if not explicitly developed for responsiveness.		Widely used in trials. Excellent inter-rater variability. Different reader algorithms available (fix or sliding scale for adjudication, paired reading …).
SES-CD	Cons	Relative complex. Exact weight of each variable to be better clarified. Unvalidated thresholds for remission and response.	Not developed with focus on responsiveness.	Limited prognostic value of sum score.	Agreement and adjudication more complex for more granular scores as compared with categorical scores. No adjustment for missing segments due to sum score. Not developed for postoperative anatomy.

CDEIS, Crohn’s Disease Endoscopic Index of Severity; EMA, European Medicines Agency; eMS, endoscopic Mayo Score; FDA, Food and Drug Administration; SES-CD, Simple Endoscopic Score for Crohn’s Disease; UCEIS, Ulcerative Colitis Endoscopic Index of Severity.