Histologic Healing Is More Strongly Associated with Clinical Outcomes in Ileal Crohn's Disease than Endoscopic Healing

BACKGROUND & AIMS: Deep remission, based on clinical remission and evidence of healing during endoscopic evaluation, are goals of medical treatments for Crohn's disease (CD). We investigated whether histologic healing is associated with outcomes of patients with CD ileitis. METHODS: We performed a retrospective study of 101 patients with CD (52% male) isolated to the terminal ileum who had a colonoscopy between September 2005 and June 2015. Our analysis included patients in clinical remission at colonoscopy who had biopsies collected from colon and ileum. The ileum was evaluated for endoscopic healing (no ulceration) and histologic evidence of healing (no active inflammation, erosions, ulceration, or neutrophil infiltration). We compared times of clinical relapse-free survival, medication escalation, corticosteroid use, or hospitalization secondary to disease activity between patients with and without histological and endoscopic healing, followed for a median 21 months. We identified factors associated with survival using Kaplan Meier analysis and Cox proportional hazard model. RESULTS: At ileo-colonoscopy, 63% of patients had endoscopic healing and 55% had histologic evidence of healing. The level of agreement between endoscopic and histologic activity was fair (62%, K = 0.2250, P = .0064). Forty-two patients had clinical relapse, 45 had medication escalation, 30 required corticosteroids, and 17 were hospitalized (3 required surgery). On multivariate analysis, only histologic healing was associated with decreased risk of clinical relapse (hazard ratio [HR], 2.05; 95% CI, 1.07-3.94; P = .031), medication escalation (HR, 2.17; 95% CI, 1.2-3.96; P = .011), and corticosteroid use (HR, 2.44; 95% CI, 1.17-5.09; P = .018). No factors were associated with hospitalization. CONCLUSIONS: In patients with ileal CD in clinical remission, histologic healing but not endoscopic healing is associated with decreased risk of clinical relapse, medication escalation, or corticosteroid use.