The American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) have announced the release of revised classification criteria for rheumatoid arthritis (RA). Classification criteria are the standard and accepted means by which researchers define people as having or not having a given disease, helping to standardize recruitment into clinical trials and other research studies. This allows for the study of treatments for RA at much earlier stages of the disease before joint damage occurs ultimately leading to better patient outcomes. Although not intended as criteria for diagnosis in clinical practice, with some additional research, classification criteria may be modified and adopted for such use.

RA is a chronic disease that causes pain, stiffness, swelling, and limitation in the motion and function of multiple joints. Although joints are the principal body parts affected by RA, inflammation can develop in the organs as well. An estimated 1.3 million Americans have RA, and the disease typically affects women twice as often as men.

The previous criteria were created in 1987. Since that time, new therapies have emerged that can prevent joint damage in people with RA. According to the lead author of the new criteria, the old criteria were a barrier to the study of treatments designed to prevent joint damage in RA, as many patients did not fulfill the criteria until the disease was well advanced.

The new diagnostic criteria for RA requires that at least one joint to be swollen, signaling the presence of synovitis, excluding joints typically involved in osteoarthritis (e.g., distal interphalangeal joints) and that symptoms are not better explained by another diagnosis such as lupus or gout. To be classified as “definite RA,” patients must receive a score of at least 6 of a possible 10. The scoring system takes into consideration the number and site/size of involved joints, laboratory tests of inflammation and autoimmunity, and symptom duration.

The 24-member expert panel also identified four additional criteria essential for determining the probability of a diagnosis of RA:

• The pattern and extent of joint involvement
• The acute phase response
• Serologic findings
• Duration of signs and symptoms of synovitis

An additional change since the 1987 RA classification criteria was the elimination of morning stiffness, since the panel determined that morning stiffness lasting more than 1 hour could not discriminate among the inflammatory arthritides, or even between inflammatory and noninflammatory arthritis. The presence of joint erosions on radiographs a late finding in RA was also omitted from the criteria because of its new emphasis on early diagnosis.

1. Neogi T, Aletaha D, Silman AJ, et al. The 2010 American College of Rheumatology/European League Against Rheumatism classification criteria for rheumatoid arthritis: phase 2 methodological report. Arthritis Rheum. 2010;62(9):2582-2591. Abstract available at: http://onlinelibrary.wiley.com/doi/10.1002/art.27580/abstract. Accessed August 12, 2010.

Posted in News Service
This entry was posted on Thursday, August 12th, 2010 at 12:00 pm.