Predictors and outcomes of histological remission in ulcerative colitis treated to endoscopic healing.
Background: Clinical remission is the recommended treatment target in ulcerative colitis. The predictors and outcomes of achieving histologic remission within a treat-to-target paradigm are not well established. Aim: To evaluate the predictors and outcomes of achieving histologic remission in patients with ulcerative colitis treated-to-target of endoscopic healing (modified Mayo endoscopy score 0 or 1).
Methods: We conducted a retrospective cohort study in adults with active ulcerative colitis (modified Mayo endoscopy score 2 or 3), whose treatment was iteratively optimised to achieve endoscopic healing. We identified predictors of achieving histologic remission, and outcomes (risk of symptomatic relapse, and ulcerative colitis-related hospitalisation and/or surgery) of achieving histologic remission vs persistent histologic activity, using Cox proportional hazard analysis.
Results: Of the 411 patients with clinically active ulcerative colitis, 270 achieved endoscopic healing. Of the 270 patients, 55% simultaneously achieved histologic remission. Depth of endoscopic healing at final endoscopic assessment was the only independent determinant of histologic remission (modified Mayo endoscopy score 0 vs 1: odds ratio, 0.31 [95% confidence intervals, 0.18-0.52]). Over 28 months, achieving histologic remission was associated with a lower risk of clinical relapse (1-year cumulative risk: 18.7% vs 29.5%; adjusted hazard ratio, 0.56 [0.37-0.85]), and lower risk of hospitalisation (hazard ratio, 0.44 [0.20-0.94]). The incremental benefit of achieving histologic remission was observed only in patients achieving Mayo endoscopy score 1, but not Mayo endoscopy score 0.
Conclusions: In patients with active ulcerative colitis treated-to-target of endoscopic healing, 55% simultaneously achieved histologic remission. Histologic remission, particularly in patients achieving modified Mayo endoscopy score 1, was associated with favourable outcomes. Treating to a target of histologic remission over endoscopic healing requires prospective evaluation.