Researchers used to believe that certain treatments for rheumatoid arthritis prevented patients from developing gout - another type of painful arthritis.
However, a recent study showed patients with rheumatoid arthritis can get gout.
"Get tested for arthritis if you have joint pain."
"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," said lead author Eric Matteson, MD, of the Mayo Clinic.
"Awareness that gout does exist in patients with rheumatoid arthritis hopefully will lead to better management of gout in those patients," he said.
Gout and rheumatoid arthritis are two different diseases that are treated differently. Rheumatoid arthritis is an autoimmune disease, meaning the immune system mistakenly attacks healthy tissues. These attacks cause joint pain and inflammation.
Gout occurs when the body makes too much uric acid or cannot flush out uric acid. When this happens, uric acid forms crystals in the joints that cause inflammation and pain.
In addition, gout has been linked to obesity.
Researchers believed patients with rheumatoid arthritis did not get gout because they took high doses of aspirin - a drug that treats pain but also happens to help the kidneys flush out uric acid.
Today, aspirin is not as commonly used to treat rheumatoid arthritis as it was before.
According to Dr. Matteson, the drop in aspirin use combined with a rise in obesity may be why more rheumatoid arthritis patients are developing gout.
For their study, Dr. Matteson and colleagues looked at 813 patients diagnosed with rheumatoid arthritis between 1980 and 2007. The participants were followed until their death or April 2012.
Over the course of the study, 22 patients (2.7 percent) developed gout. Gout became more common in these patients after 1995.
Rheumatoid arthritis patients had the same risk factors for gout as those without rheumatoid arthritis. These factors included being overweight, being older and being male.
While this study showed that only a small number of rheumatoid arthritis patients developed gout, it still suggests that it is possible to get gout with rheumatoid arthritis. The research was presented at the American College of Rheumatology's annual scientific meeting. As such, the study has yet to be peer-reviewed for publication in a scientific journal.