Dr. Emery explained that, according to the ACR/EULAR criteria, the first step in determining if a patient has RA is using imaging to detect synovitis. The second step is to check for radiological erosion [indicative of more advanced disease], and the third uses a combination of variables to make the diagnosis, including joint involvement, serology, duration of synovitis, and acute phase reactants. According to the criteria, involvement of more than 10 joints, including small joints, has a very strong impact on a patient’s likelihood of having RA.
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Explore This IssueJuly 2013
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Dr. Emery said the criteria have removed the need for symmetry of joint involvement and presence of structural damage in order to diagnose patients and begin therapy. “If I told you that you had mild disease I think you’d want the best therapy,” he said. “You don’t not give antibiotics to a chest infection just because it’s not bilateral pneumonia.”
Being able to diagnose RA as an evolving disease is also positive for drug development, he said. “Drugs can now be developed and licensed at this early stage, whereas you used to have to call it pre-RA and I can tell you the FDA [Food and Drug Administration] was just not interested. Now it’s RA and they are.”
But the criteria aren’t perfect, Dr. Emery said. For example, imaging synovitis and erosion isn’t very straightforward. “For our typical patient, a middle-aged female with puffy hands, it’s extremely difficult to know if its synovitis or extraarticular soft tissue,” he said. “What you want to know is what’s in the joints and I think, ultimately, we should have imaging as part of our criteria.”
Dr. Emery referenced a study from 2010 that assessed the role of power Doppler ultrasound in an early inflammatory cohort and involved the development of a diagnostic algorithm for prediction of persistent inflammatory arthritis.2 Researchers found in that patients with one or two positive predictors, power Doppler ultrasound increases the probably of identifying persistent inflammation from 4%–27% to 69%–95%.
The study, he said, suggests the main role for ultrasound in diagnosed inflammatory arthritis is in patients who are seronegative.
Getting to Remission
Dr. Emery pointed out that the 2012 ACR recommendations set the target for disease activity as either remission or low disease activity.3 Getting there, however, is complicated.
For one, treating mild patients less aggressively may not be very effective. “If you allow methotrexate [MTX] to be given in the presence of inflammation eventually you can change the signaling molecules within the cells which make that individual much more resistant to later therapy,” he said.