BACKGROUND Although achieving histologic remission in ulcerative colitis is established, the incremental benefit of achieving histologic remission in patients with Crohn disease (CD) treated to a target of endoscopic remission is unclear. We evaluated the risk of treatment failure in patients with CD in clinical and endoscopic remission by histologic activity status.

METHODS In a single-center retrospective cohort study, we identified adults with active CD who achieved clinical and endoscopic remission through treatment optimization. We evaluated the risk of treatment failure (composite of clinical flare requiring treatment modification, hospitalization, and/or surgery) in patients who achieved histologic remission vs persistent histologic activity through Cox proportional hazard analysis.

RESULTS Of 470 patients with active CD, 260 (55%) achieved clinical and endoscopic remission with treatment optimization; 215 patients with histology were included (median age, 33 years; 46% males). Overall, 132 patients (61%) achieved histologic remission. No baseline demographic, disease, or treatment factor was associated with achieving histologic remission. Over a 2-year follow-up, patients with CD in clinical and endoscopic remission who achieved histologic remission experienced a 43% lower risk of treatment failure (1-year cumulative risk: 12.9% vs 18.2%; adjusted hazard ratio, 0.57 [95% confidence interval, 0.35-0.94]) as compared with persistent histologic activity.

CONCLUSIONS Approximately 61% of patients with active CD who achieved clinical and endoscopic remission with treatment optimization simultaneously achieved histologic remission, which was associated with a lower risk of treatment failure. Whether histologic remission should be a treatment target in CD requires evaluation in randomized trials.