The purpose of this study is to estimate and compare the incidence of overall malignancy, serious infection, and opportunistic infections between new users of ustekinumab and new users of other biologic therapies among adult participants with Crohn's disease (CD) or ulcerative colitis (UC).

Inclusion Criteria:

• Adult men and women with CD or UC who are new users of ustekinumab or the comparator drugs during the study period
• Participants must have at least 1 year of enrollment history with the DoD EHR database immediately prior to new use (that is, exposure index date) of ustekinumab or the comparator drugs

Exclusion Criteria:

• Participants below 18 years of age on the exposure index date
• Participants who do not meet the definition for CD or UC prior to or on the exposure index date
• Participants with any records of human immunodeficiency virus (HIV) diagnosis, organ or tissue transplant, or malignancy (excluding non-melanoma skin cancer [NMSC]) at any time prior to or on the exposure index date
• Participants with a physician diagnosis of rheumatoid arthritis, ankylosing spondylitis, or psoriatic arthritis within 12 months prior to or on the exposure index date
• In the analysis of infection outcomes, participants diagnosed with the same infection of interest both within 60 days prior to or on the exposure index date and within 60 days after the exposure index date will be excluded

The study population will include participants with Crohn's Disease (CD) or Ulcerative Colitis (UC) who are new users of ustekinumab and new users of the comparator drugs which will be identified from the Department of Defense (DoD) Electronic Health Records (EHR) database.