One‐year clinical outcomes with biologics in Crohn's disease: transmural healing compared with mucosal or no healing

Summary Background While mucosal healing has been proved to predict relevant clinical outcomes in Crohn's disease (CD), little is known about the long‐term significance of transmural healing. Aims To prospectively assess the 1‐year clinical outcomes in CD patients achieving transmural healing following treatment with biologics, and to compare them with those in patients reaching only mucosal healing or no healing. Methods Observational longitudinal study, evaluating 1‐year outcomes in terms of steroid‐free clinical remission, rate of hospitalisation and need for surgery in a group of CD patients treated with anti‐tumour necrosis factor (TNF) alpha for 2 years. Bowel sonography was used in all patients to determine transmural healing. Results Of 218 patients who completed a 2‐year treatment course with anti‐TNF alpha, 68 (31.2%) presented transmural (plus mucosal) healing (bowel wall thickness ≤3 mm at bowel sonography), 60 (27.5%) mucosal healing only, and 90 (41.3%) did not achieve any intestinal healing. Transmural healing was associated with a higher rate of steroid‐free clinical remission (95.6%), lower rates of hospitalisation (8.8%) and need for surgery (0%) at 1 year compared to mucosal (75%, 28.3% and 10%, respectively) and no healing (41%, 66.6% and 35.5%, respectively) ( P < 0.001). Furthermore, transmural healing was associated with longer intervals until clinical relapse (HR, hazard ratio 0.87, P = 0.01), hospitalisation (HR 0.88, P = 0.002) and surgery (HR 0.94, P = 0.008) than mucosal healing. Also among patients discontinuing treatment with biologics, transmural healing predicted better clinical outcomes at 1 year than mucosal healing ( P = 0.01). Conclusions Transmural healing is an ambitious and powerful treatment goal associated, to a greater extent than mucosal healing, with improvement of all clinical outcomes. Additionally, transmural healing is associated with better long‐term clinical outcomes than mucosal healing also after discontinuation of biologics.