Lin YS, et al. - In patients with Crohn's disease (CD) undergoing abdominal surgery, researchers evaluated the impacts of pre-operative anti-tumour necrosis factor (TNF) therapy on post-operative complications within 30 days post-operatively. Via performing a systematic review with meta-analysis on articles found in MEDLINE, Embase, Cochrane Library, Scopus, and the International Clinical Trials Registry Platform until September 2018, 20 studies (7115 patients) have been involved. According to findings, patients with CD who have been pre-operatively exposed to anti-TNF agents have a higher risk of post-operative infectious complications vs those who have not been exposed to these agents, particularly in countries with high CD. They recommend postponing elective surgery or monitoring postoperatively these patients carefully.