WASHINGTON -- Refuting a belief long held by many physicians, a Mayo Clinic study found that rheumatoid arthritis patients also can get gout. The research is among several studies Mayo Clinic is presenting at the American College of Rheumatology annual meeting in Washington. Researchers also found that gut bacteria has potential to treat autoimmune disorders, rheumatoid arthritis patients are at higher risk for cancer, broken bones put rheumatoid arthritis patients in greater danger of heart disease and death, and corticosteroids are a mainstay of rheumatoid arthritis treatment even as new drugs emerge.
VIDEO ALERT: A video interview with Dr. Matteson is available for journalists to download on the Mayo Clinic News Network
The gout study shows that, contrary to conventional wisdom, rheumatoid arthritis patients aren't immune to the nation's obesity-fueled gout epidemic, says lead author Eric Matteson, M.D., chair of the Division of Rheumatology at Mayo Clinic in Rochester, Minn. The two are distinct conditions, treated differently. Rheumatoid arthritis is an autoimmune disease in which the immune system mistakenly attacks tissues, inflaming joints. In gout, the body produces too much uric acid or has problems flushing it out, and urate crystals build up in joints, causing inflammation and intense pain.
The reason it was thought that rheumatoid arthritis patients didn't get gout likely had to do with the way rheumatoid arthritis used to be treated, Dr. Matteson says. Such patients used to be given aspirin in high doses, and that coincidentally helped their kidneys expel uric acid. Aspirin is no longer used much for rheumatoid arthritis, and that, combined with a rise in obesity, is likely fueling gout in rheumatoid arthritis patients, he says.
"It is probably true that flares of rheumatoid arthritis in some cases might have actually been flares of gout, and that the gout wasn't diagnosed; it wasn't realized that it was a coexistent problem," Dr. Matteson says. "Awareness that gout does exist in patients with rheumatoid arthritis hopefully will lead to better management of gout in those patients."
Researchers studied 813 patients diagnosed with rheumatoid arthritis between 1980 and 2007 and followed them as long as they were alive and in the county, until last April. The study used the Rochester Epidemiology Project, a National Institutes of Health-supported pool of Olmsted County, Minn., patient medical records from Mayo and other health care providers.
Twenty-two patients developed gout over the study period, most often in the big toe. Gout was more common in patients diagnosed with rheumatoid arthritis from 1995 on. The risk factors for gout were the same as in the general population: being overweight, being older and being male.
Other Mayo studies being presented at the rheumatology conference found that: