Prognostic significance of endoscopic remission in patients with active ulcerative colitis treated with oral and topical mesalazine: a prospective, multicenter study.

Background: It has been recommended that the treatment of active ulcerative colitis (UC) should be continued until complete healing of endoscopic lesions. However, the evidence supporting this recommendation is scanty. Aims of the present study were to assess the rate of patients with active UC who achieve clinical but not endoscopic remission after treatment with oral plus topical mesalazine and to compare the rate of relapse in patients with clinical/endoscopic remission and those with only clinical remission.

Methods: Patients with active mild or moderate UC were eligible. All patients received mesalazine, 4 g/day orally and 2 g/day per rectum for 6 weeks. Those achieving clinical remission underwent colonoscopy: afterwards, all received maintenance treatment with oral mesalazine, 2 g/day orally for 1 year. Clinical remission was defined as normal frequency of bowel movements with formed stools, no abdominal pain, and no blood in the stools. Endoscopic remission was defined as normal-appearing mucosa or only mild redness and/or friability, without either ulcers or erosions.

Results: In all, 81 patients were enrolled. Sixty-one (75%) achieved clinical remission. Endoscopic activity was still present in five (8%). The cumulative rate of relapse at 1 year was 23% in patients with clinical and endoscopic remission and 80% in patients with only clinical remission (P < 0.0001).

Conclusions: Persistence of endoscopic activity is quite infrequent in patients with active UC achieving clinical remission after a 6-week treatment with oral plus topical mesalazine, but is a very strong predictor of early relapse.