Rheumatoid arthritis (RA) is a chronic systemic disorder that strikes approximately 1% of the world's population.1,2 The onset is usually at a young age (15-45 years), and occurs more frequently in women than in men.3 The exact etiology of RA is not well understood, and the factors that initiate the inflammatory process are unknown, but it is clearly an autoimmune disease involving T-lymphocytes, B-lymphocytes, macrophages, and cytokines.3 The body's immune cells are unable to differentiate between self and nonself, and begin to target the joint tissue. T-lymphocytes produce proinflammatory cytokines and produce cytotoxic substances that lead to the erosion of bone and cartilage. Activated B-lymphocytes produce plasma cells, which form antibodies that attack joint tissues. Macrophages begin to release prostaglandins and cytotoxins to cause further injury and inflammation.3
RA is classically characterized by the presence of chronic inflammation and symmetric erosive synovitis, leading to joint deterioration and deformity. Early in the disease course, patients may develop vague, generalized symptoms such as fatigue, malaise, diffuse musculoskeletal pain, and morning stiffness in joints that lasts for longer than 30 minutes.4 In the majority of cases, these symptoms develop insidiously over weeks to months.4 The small joints of the hands, wrists, and feet are most likely to be involved and may appear swollen and feel warm to the touch. At later stages, joints of the fingers may become deformed because of the erosive effect of the disease on bones, tendons, and ligaments. RA patients occasionally have extra-articular involvement associated with their disease such as vasculitis, Sjögren, rheumatoid nodules, and pulmonary or cardiac complications.3
There are no specific laboratory tests that establish a diagnosis of RA, but several tests suggest the diagnosis.4 About 60% to 70% of RA patients will test positive for rheumatoid factor (RF), and approximately 25% of patients will test positive for antinuclear antibody (ANA). Erythrocyte sedimentation rates and C-reactive protein (CRP) levels may also be elevated, although these are nonspecific markers of inflammation. A complete blood count (CBC) may reveal anemia of chronic disease or thrombocytopenia.3
According to the American College of Rheumatology, a diagnosis of RA is made when patients meet four of the following seven criteria for at least 6 weeks: morning stiffness (lasting more than 1 hour), swelling in three or more joint areas, swelling in the hand or wrist joints, symmetrical arthritis, rheumatoid nodules, positive RF, and radiological changes (joint erosions or decalcifications).5
With time, RA can vary in activity and severity among individuals and within the same patient. For this reason is it important to assess disease duration, activity level, and prognostic factors for each patient. Disease duration is classified as "early" if it has persisted for <6 months, "intermediate" if for 6 to 24 months, and "long" if for >24 months. Several validated instruments (the RA Disease Activity Score and Simplified Disease Activity Index, to name two) are available to measure RA disease activity more objectively and consistently; these instruments ...