Circadian RA Study in Rheumatoid Arthritis Subjects

Rheumatoid arthritis (RA) is a chronic and debilitating disease. However, the symptoms of RA show variation over the course of the day, with worsening symptoms in the morning. This worsening of symptoms in the morning is correlated with an increase in inflammation in the body. Biologic therapies, such as Enbrel (etanercept), appear to improve energy, pain and quality of life in patients with RA, and these changes may occur before a doctor is able to detect changes during the patient's physical examination. It is possible that a patient's response to biological agents can be rapidly determined by assessing circadian activity (also called "rest-activity circadian rhythms" or RAR). Currently, wrist actigraphy bands, which are worn for a period of time, can reliably provide information about RAR. Wrist actigraphy bands are small electronic devices worn on the wrist (similar to a watch) that records the subject's level of activity throughout the day. Studies in osteoarthritis and in rheumatoid arthritis have found subjects with joint pain to have significant differences in RAR, and disrupted RAR has been associated with disease activity. This study will provide information about 24-hour circadian activity rhythms before and after 3-4 weeks of Enbrel treatment in study subjects with active rheumatoid arthritis. The study will assess patients who are starting on Enbrel that has been prescribed by their doctor.