The revised classification, announced this week by the American College of Rheumatology and the European League Against Rheumatism, will allow researchers to recruit patients for clinical trials earlier in the disease process, says Boston University associate professor of medicine and epidemiology Tuhina Neogi , MD , PhD.
It may also lead to earlier treatment of some patients with suspected rheumatoid arthritis (RA), she says, although that was not the purpose of the revision.
The new criteria appear in the September (2010) issue of Arthritis & Rheumatism.
"It is likely that this will be adopted into clinical practice, but many other factors must be considered for a diagnosis of rheumatoid arthritis," Neogi tells WebMD. "The rheumatologist has to take into account the patient's specific risk factors and a whole host of other things. The process is very nuanced."
Early RA Diagnosis Is Difficult
An estimated 1.3 million people in the U.S. have rheumatoid arthritis. The disease strikes twice as many women as men.
RA is a progressive disease, mainly characterized by inflammation of the lining of the joints, but it can also affect other organs.
Early diagnosis of RA is complicated by the fact that its symptoms mimic those of other common conditions including osteoarthritis, gout, lupus, and infection-related joint inflammation.
It has been almost 25 years since the classification criteria for RA has been updated. Since that time much has been learned about the disease and new treatments have been introduced that can prevent the joint damage and bone erosion characteristic of advanced RA.
Under the old classification system many patients did not meet the definition for RA until joint damage was evident.
"The goal of today's treatments is to keep people from reaching the point where they have bone erosion and joint deformities," Neogi says.
Morning Stiffness Not Specific to RA
Under the new system, patients with inflamed joint linings with no other obvious cause will be evaluated for RA using a 10-point analysis that includes such factors as symptom duration and the number and size of the joints involved.
A score of 6 or more out of 10 is needed for a classification of "definite RA."
The new classification system includes blood testing for the RA antibody ACPA, which is now widely used in clinical practice but did not exist when the old system was adopted, Neogi says.
Eliminated from the revised criteria: morning stiffness in the joints that lasts for at least one hour.
"Morning stiffness is seen in inflammatory arthritis, but it is not specific for RA," Neogi says. "It is not particularly helpful for predicting whether or not someone will end up with that diagnosis."
The new system will help researchers better assess new treatments to prevent joint damage by increasing the pool of patients eligible for clinical trials before joint damage occurs, senior author Gillian Hawker, MD, says in a news release.
He says the next logical step would be to use these classification criteria to develop diagnostic guidelines to aid in the diagnosis of RA.