TNF and inflammatory bowel disease: Sixth, although patients propensity scores matched by disease location (for CD), disease extent (for UC), disease duration, healthcare utilization, Charlson Comorbidity Index, as well as use of steroids, immunomodulators, and anti-TNF before index, we cannot rule out that nuances of IBD disease severity may have been imbalanced and may thus have impacted the risk of certain outcomes.