Study: rheumatoid arthritis affects different joints in different ways

Researchers have found that rheumatoid arthritis afflicts different joints in different ways. That means that an effective treatment for arthritic hips may be less effective for swelling and pain in the knees.

“We showed that the epigenetic marks vary from joint to joint in diseases like rheumatoid arthritis,” said Gary Firestein, M.D., with the University of California, San Diego, and one of the study’s authors. “Even more importantly, the differences involved key genes and pathways that are designed to be blocked by new RA treatments. This might provide an explanation as to why some joints improve while others do not, even though they are exposed to the same drug.”

Findings could lead to different treatments

Firestein and colleagues in Pennsylvania and China touted two key findings of study, which focused on specialized cells that line the inside of joints:

• Rheumatoid arthritis uses different cellular and molecular processes than osteoarthritis. Rheumatoid arthritis is an autoimmune disorder, while osteoarthritis is caused by wear and tear on the joints.
• Rheumatoid arthritis has joint-specific effects.

The findings could influence how clinicians assess rheumatoid arthritis and treat it, and how they evaluate drugs, the researchers said.

“The clinical relevance of joint-specific pathways could be important when considering how drugs are tested in RA clinical trials,” they wrote. “Current metrics do not distinguish which joints respond; instead, only the total number of swollen and tender joints is counted. Thus, investigators could potentially overlook site-specific responses or patterns.”

The study is available here.

A widespread affliction

Rheumatoid arthritis occurs when the body’s autoimmune system, which defends against invaders like dangerous bacteria, mistakenly attacks the joints. It inflames the lining of multiple joints, causing pain, swelling, redness and sometimes deformity. There is no cure, but some drugs are used to treat pain and inflammation, and prevent deformities.

The Centers for Disease Control and Prevention estimates about 1.5 million U.S. adults have rheumatoid arthritis. The disease can cost between $61,000 and $122,000 over the course of a lifetime, the agency said.

Rheumatoid arthritis can substantially affect the lives of those who suffer from it. They are significantly more likely to change occupations, reduce work hours, lose their jobs or retire early, the CDC said.

More hopefully, the Arthritis Foundation says self-care can help people manage symptoms and improve their quality of life. The foundation recommends:

• Eating foods that are rich in antioxidants, which can help control and reduce inflammation
• Resting when joints are painful, swollen or stiff
• Exercising with low-impact aerobics and activities to promote muscle-strengthening and flexibility
• Using heat and cold therapies, from taking warm baths to soothe stiff and painful joints to applying ice to areas causing acute pain
• Using supplements such as turmeric or fish oil, but only after discussing them with your health care provider

The Arthritis Foundation describes the causes, symptoms and treatment of rheumatoid arthritis here. The Centers for Disease Control and Prevention offers a more clinical backgrounder here.

If you have arthritis, talk with your health care provider about the best way to manage your condition. If you don’t have a provider, you can find one here.