C-reactive protein fails to predict rheumatoid arthritis

Inflammatory marker remains a good way to monitor the disease's progress but not to diagnose it or determine who will develop it.

By Victoria Stagg Elliott, AMNews staff. Jan. 22, 2007.

A measurement of C-reactive protein, an indicator of acute inflammation, does not forecast who will develop rheumatoid arthritis, according to a study published last month.

Researchers from Brigham and Women's Hospital and Harvard Medical School in Boston worked with blood samples provided by 27,939 participants in the Women's Health Study, a randomized trial exploring the impact of aspirin and vitamin E on cancer and cardiovascular disease risk. Of this group, 90 received a diagnosis of rheumatoid arthritis that fit American College of Rheumatology guidelines. But after adjusting for age, body mass index, smoking and impact of the intervention this trial was studying, the disease's occurrence did not correlate with CRP measures.

"A single CRP level did not predict increased risk of RA," wrote the authors. Physicians responded that the study, published in the Dec. 11/25, 2006, Archives of Internal Medicine, highlighted this disorder's complicated nature. Specifically, many suspect that it has a variety of underlying mechanisms that translate to the same autoimmune response that destroys healthy tissue.

"It's a very individualized illness," said Adam Rindfleisch, MD, assistant professor of family medicine at the University of Wisconsin, Madison. "There are different inflammatory factors that come into play, and I think we will start to discover that there are a lot of different things that can be going on biochemically."