text_1: Blood test that could predict arthritis risk
text_2: This release from the University of Oxford describes a new blood test that researchers there developed after zeroing in on the protein that collects in the joints of people with rheumatoid arthritis. The presence of the protein can predict the advance of rheumatoid arthritis many years before arthritis symptoms develop, according to the research findings published in the journal Annals of the Rheumatic Diseases. Among some of the 2,000 individuals who were part of the study, the protein, called tenascin-C, was found as many as 16 years before disease symptoms appeared. The release does a good job describing the science behind the test but may leave readers wondering, “What’s next?” That’s because we aren’t told when and where the test will be available and there’s no mention of early treatment strategies — what the options are, what they entail, how long it lasts and what it might cost. Most doctors screen for rheumatoid arthritis among patients presenting with joint symptoms. Tests to diagnose RA aren’t perfect but have gotten better over time. This news release highlights a new test that may be able to identify patients who have not yet been diagnosed. As such, it would be predicting future RA in patients who do not yet have symptoms or other findings such as arthritis changes on x-rays. Identifying patients with so-called “pre-RA” might appear to be a good thing, but it may not be as simple as implied in this news release. First, it is one thing to retrospectively examine whether blood samples performed years earlier can identify people we’ve already classified. The next logical step would be to prospectively see if we can take patients who don’t have any symptoms and use the test to say “positive or negative” and then wait to see if the test correctly predicts a future diagnosis. This is complicated by the need to say who should we use the test on. Everyone? Someone who may be at risk for other reasons? It isn’t clear and the news release doesn’t help us. Second, since no test is perfect and there inevitably will be false-positives, what does it mean to label someone as being likely to develop future RA if in fact they won’t? Third, even if the test is correct, it isn’t clear what to do with the results. Should we start treating these patients with medications to prevent future symptoms? If the treatments had no side effects, one could argue to do so. But we know that the treatments for RA all have side effects, some quite serious. For those with debilitating symptoms, the risks of such medications may be justified. But for someone who has no such symptoms, it isn’t as clear. One would like to see studies saying that use of this test result leads to better outcomes. No such data exists. Finally, there is no effort to state what would be the potential costs of using such a test in routine practice. One would not only need to consider the cost of the test itself, but also the downstream costs associated with treatment and the potential savings in terms of RA complications avoided.