TNF and ulcerative colitis: Abbreviations: Anti-TNF, anti- tumor necrosis factor; BMI, body mass index; C. difficile infection, Clostrideoides difficile infection; C. innocuum, Clostridium innocuum; CMV, cytomegalovirus; IBD, inflammatory bowel disease, OR, Odds Ratio; CI, confidence interval; UC, ulcerative colitis; UST, ustekinumab; VDZ, vedolizumab.