Abstract

Background and aims: Ulcerative colitis disease activity indices offer good statistical power but small changes in these indices may not be clinically important. There are no validated definitions of remission or of significant improvement for these indices. The use of clinically important end points would strengthen the validity of study outcomes. Our aims were to identify objective end points in standard disease activity indices for remission and for improvement in ulcerative colitis.

Methods: Sixty six consecutive patients with ulcerative colitis provided information about remission status and their disease activity. At a return visit 1–14 months later, these patients provided information about the change in their disease activity, and non-invasive indices were measured.

Results: Specific objective end points for determining remission with four standard indices and a quality of life instrument were determined (St Mark’s <3.5, ulcerative colitis disease activity index <2.5, simple clinical colitis activity index (SCCAI) <2.5, Seo <120, and inflammatory bowel disease quality of life index (IBDQ) >205). These cut offs also identified patients who met a regulatory definition of remission. Specific objective end points for clinical improvement in two non-invasive indices and a quality of life instrument were determined with good sensitivity and specificity (SCCAI decrease >1.5, Seo decrease >30, IBDQ increase >20).

Conclusions: We found specific cut off values for disease activity indices that identify patients who have significantly improved or achieved remission in an objective, sensitive, and specific manner. These cut offs should help in the interpretation of the outcomes of clinical trials in ulcerative colitis.