Background: Mucosal healing (MH) has been associated with improved outcomes in ulcerative colitis but factors associated with MH are not well defined.

Methods: Consecutive patients with ulcerative colitis in clinical remission (Mayo symptomatic subscore = 0) who had at least 1 colonoscopy since diagnosis from 6 centers were included. For patients who had at least 2 colonoscopies during follow-up, each colonoscopy was reviewed to define whether they had early MH (Mayo endoscopic subscore reduced to 0 within 3 yr of clinical remission). Factors associated with MH and early MH were determined using logistic regression.

Results: Two hundred thirty-seven patients with ulcerative colitis (mean age 50.39 ± 14.10 yr; 56.5% male) were included. Independent factors for MH were clinical remission >3 years (odds ratio [OR] 4.0; 95% confidence interval [CI], 1.2-13.1), mild/moderate mucosal inflammation (OR 3.3; 95% CI, 1.3-8.5), and immunosuppressant use (OR 4.6; 95% CI, 1.5-14.6). Among patients who had ≥2 of above factors, 74% achieved MH, whereas only 39% with <2 factors achieved MH (P < 0.001). Of patients in clinical remission <1 year, 1 to 3 years and >3 years, 30%, 45.9%, and 62.9% achieved MH, respectively. Immunosuppressant therapy was associated with early MH (P = 0.025). In multivariate analysis, patients with previous mild inflammation were more likely to achieve early MH than those with moderate/severe inflammation (OR 2.8; 95% CI, 1.2-6.2).

Conclusions: A longer disease remission, previous less severe mucosal inflammation, and immunosuppressant use are associated with MH. Severity of mucosal inflammation and use of immunosuppressant are also associated with early MH.