Arthritis causes 750,000 hospitalizations and 36 million ambulatory care visits annually within the United States which are estimated to cost $51 billion.
Arthritis is a disease of the joints that involves inflammation of one or more joints. Approximately 50% of Americans over 65 suffer from some form of arthritis (1). There are many forms arthritis, the most common form is osteoarthritis. Osteoarthritis is a result of trauma or infection of the joint, or simply old age (2). The other major form of arthritis is rheumatoid arthritis, which is an inflammatory disease of autoimmune origin. Arthritis is also commonly observed in patients with a a wide variety of other autoimmune diseases, including psoriasis, hepatitis, Lyme disease, Sjogren’s disease, Hashimoto’s thyroiditis, inflammatory bowel disease (including Crohn’s disease and ulcerative colitis), sarcoidosis, and systemic lupus erythematosus (3).
The major symptom of arthritis is joint pain, which is usually accompanied by swelling and inflammation. In the case of osteoarthritis the swelling and inflammation is often caused by damage to the joint, but in the case of rheumatoid arthritis, and the other inflammatory diseases, inflammation appears to be the primary cause of the swelling and pain (4-6).
Although only 9,500 deaths are attributed to arthritis annually, it causes 750,000 hospitalizations and 36 million ambulatory care visits annually within the United States. The total cost of arthritis in the US is estimated to be a total of $86 billion annually, with $51 billion of this attributable to medical costs alone. These figures make the cost of arthritis in both terms of human suffering and in pure financial terms abundantly clear (7-9).
While the causes of osteoarthritis are relatively obvious, the etiology of rheumatoid arthritis and the arthritis associated with the inflammatory diseases is less obvious. The disease appears to start as an inflammatory response that attacks the synovial membrane lining the articulated surfaces of the joints, causeing a thickening of this membrane, and eventually leading to the erosion of the joint cartilage. However, this process can move beyond joints and into other connective tissue within the body, including ligaments, tendons and even tissues like the eye (10). A long list of genetic changes have been associated with rheumatoid arthritis, most notably certain alleles of HLA-DR, a protein that plays a major role in the immune response. Most of the genes implicated in RA play some role in the immune system, suggesting that RA is primarily an immunological disease. The role of the external factor, however, should not be discounted, since the typical age of onset for RA is between 40 and 60 (11).