An Observational Study of Lymphoma in Patients With Rheumatoid Arthritis or Crohn's Disease.

This is an observational (review of records), retrospective (research activity that is performed after the events under the study have occurred), registry study where data was collected from 3 different registries sponsored or supported by Centocor. Registries are Centocor-sponsored Therapy Resource Evaluation and Assessment Tool (TREAT™) Registry of Crohn's Disease, and in the following two Centocor-supported registries the Consortium of Rheumatology Researchers of North America, Inc. (CORRONA) registry and the Infliximab RA Registry, a subset of the National Database Registry of Rheumatoid Arthritis (NDBRRA) and of the National Databank for Rheumatic Diseases (NDB). A registry is data collection in a real life physician-patient setting. Physicians prescribe medications for rheumatoid arthritis and/or Crohns disease in accordance with their usual clinical practice and then record this information and provide it to Centocor. For this registry study, Centocor collected data from 3 registries to evaluate the risk of getting lymphoma if you have rheumatoid arthritis and/or Crohns disease and you have taken infliximab. Patients who were in one of the 3 registries and had rheumatoid arthritis and/or Crohns disease and did not take infliximab were also evaluated. This registry study does not involve the use of any investigational drugs.