by Cooper B. Wilhelm
A recent study suggests that a new blood test for assessing rheumatoid arthritis (RA) disease activity and progress may be an effective boost to existing methods. The test, commercially available as Vectra DA, is not intended to replace current ways of assessing RA, but the test's developers believe it could give people with RA and their doctors more information so they can make better decisions. According to Jeffry R. Curtis, MD, MPH, one of the authors of the study, because Vectra DA traces the "mediators of inflammation that cause disease activity," it could someday be used to not only assess a person's RA activity, but to also get a sense of how effective a given treatment option may be in the long term, distinguish between different underlying causes of disease activity, and even predict a flare.
Doctors assess a person's RA by asking about symptoms, counting the number of inflamed or otherwise affected joints, and/or ordering one or more blood tests that measure the level of inflammation in the body. X-rays and ultrasound may also be used to look for signs of joint damage.
Researchers involved in the study published online by Arthritis Care and Research point out that while these methods are still important, they might miss more subtle RA activity in the joints or mistake the effects of a different condition for those of RA. According to Dr. Curtis, if someone had both RA and fibromyalgia, for example, both conditions might cause similar symptoms. Vectra DA, however, could help distinguish which condition was actually causing the flaring up and thus needed treating.
In a 2010 study, researchers used data from a study of 20 biomarkers — chemicals in the blood — in people undergoing different treatments for RA. The researchers identified 12 biomarkers that seemed to correlate with RA disease activity. In this new study, a team with some of the same researchers tested to see whether this new 12-biomarker algorithm method, called the multi-biomarker disease activity (MBDA) score, could determine the level of RA activity in a wide range of people, and also whether it could register changes in RA activity over time.
The researchers found that their combination of biomarkers had results similar to those of the Disease Activity Score 28-CRP except in the two smallest groups, both of which consisted of people lacking the two autoantibodies that serve as common indicators of active RA. The MBDA method also registered a change in symptoms earlier than the Disease Activity Score 28-CRP.
Although Dr. Curtis conceded that this study was still "quite foundational" and there is more research to be done based on his team's findings, he pointed to numerous ongoing studies testing potential applications of Vectra DA.
Dr. Curtis mentioned a study presented last year that suggests Vectra DA can predict future joint damage so that doctors can know ahead of time if a treatment that seems to work well enough now may still leave a person at risk in the long-term.
Ongoing research also seeks to confirm whether Vectra DA could be used for RA assessment in the place of MRI or x-rays, which can take time and be inconveniently located. There is also the possibility that studies will confirm Vectra DA's ability to predict flares so that doctors may prescribe drugs to lessen their intensity before they occur.
One limitation of the study was that many of researchers involved either received funding from, hold stock in, or are employees of the company that makes the test.
Last Reviewed on July 26, 2012
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