Standardized Definition of Mild to Moderate Ulcerative Colitis Needed

Ulcerative colitis
ulcerative colitis, inflammatory bowel disease, IBD, UC
Researchers performed a systematic review of clinical trials to assess the need for a consensus on the definition of mild to moderate, active ulcerative colitis.

A systematic review published in the United European Gastroenterology Journal found that a consensus in the definition of mild to moderate, active ulcerative colitis (UC) is needed.

Researchers searched Pubmed/Embase and Scopus databases from January 2000 to January 2022 for randomized controlled trials that enrolled patients with mild to moderate UC. Of 3038 studies identified, researchers included a total of 39 in the review. Of those, 84.6% evaluated the efficacy of 5-aminosalicylic acid. The pooled study population comprised 12,046 patients. Together, the studies used a combination of 6 UC disease activity assessments.

To define mild to moderate disease, the most frequent definition was made using the UC Disease Activity Index (UCDAI; 41%) instrument. Four cutoffs to define mild to moderate activity using UCDAI were observed. The most common cutoff was a UCDAI of at least 4 and less than or equal to10 plus a sigmoidoscopy score of at least 1 and a Physician’s Global Assessment (PGA) score of 2 or lower, which was used in 9 studies.

The next most common definition relied on the Clinical Activity Index (CAI) score, in which 11 studies had 5 different CAI cutoffs to define moderate to severe disease. The most common was CAI greater than 4 in 6 studies.

The least employed instrument was the Mayo Clinic Score (MCS), which was used in 1 study, defining moderate to severe disease as MCS greater than or equal to 5 plus rectal bleeding subscore of at least 1 and Mayo Clinic Endoscopic Subscale of at least 2.

Study limitations include the high heterogeneity observed among the included studies, in part due to the discrepancies in disease activity definitions and time spans between studies.

The study authors concluded, “This review found substantial heterogeneity in the scoring indexes used and their definitions of mild to moderate active UC. Similar definition of mild to moderate active UC should be considered to minimize heterogeneity and ensure validity of future randomized controlled trials. The definition of mild to moderate active UC should combine clinic and endoscopic evaluation, in line with the current trend of making evaluations more objective and standardized.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Caron B, Jairath V, D’Amico F, et al. Definition of mild to moderate ulcerative colitis in clinical trials: A systematic literature review. United European Gastroenterol J. Published online August 27, 2022. doi:10.1002/ueg2.12283