Most baseline factors, including sex, age, BMI, related surgery, history of smoking or drinking, IBD type and clinical classification based on Montreal classification, perianal disease, disease activity, various laboratory results, prior use of biological agents, prior or concomitant medications use, duration of anti-TNF drug use, and time from the first anti-TNF dispensation to first ADA test or the end of follow-up, showed no significant difference between IBD patients with negative or positive ADA levels (Table 1). Here, TNF is linked to inflammatory bowel disease.