Remission in trials of ulcerative colitis: What does it mean?

Measurement of disease activity in ulcerative colitis is critical in determining whether new therapies are effective, but there is no gold standard for measuring disease activity in ulcerative colitis. Not only is no single disease activity index widely accepted, but there is also no generally accepted definition of remission. Remission rates vary by as much as two-fold depending on the definition of remission. When two trials of 4.8 g mesalamine were evaluated according to the remission endpoint used for two trials of infliximab for active ulcerative colitis, apparent remission increased from 20.0% to 44.9%. Physicians and healthcare professionals should pay attention to the definition of remission being used as a measure of clinical efficacy in clinical trials. Interobserver variation in endoscopy scoring alone can influence the absolute remission rate by 10%-16%. Registration remission, which depends primarily on endoscopy and absence of rectal bleeding, is most subject to this influence. Clinical remission (absence of rectal bleeding and normal stool frequency) is used in clinical practice. Steroid-free remission is what matters to patients. The definition of remission needs to be validated if the results of clinical trials are to be compared.