Anti-TNF therapies may reduce Alzheimer's risk among people with rheumatoid arthritis

Anti-TNF therapies commonly used to treat rheumatoid arthritis have been found to potentially reduce the risk of developing Alzheimer's dementia among people with rheumatoid arthritis, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Atlanta.

Rheumatoid arthritis is a chronic disease that causes pain, stiffness, swelling, and destruction of the joints. People with RA often experience limitation in the motion and function of multiple joints. Though joints are the principal body parts affected by RA, inflammation can develop in other organs as well. An estimated 1.3 million Americans have RA, and the disease typically affects women twice as often as men.

A complication of chronic inflammation in RA is amyloidosis, caused by excess deposits of amyloid proteins in different organs, which can cause harmful effects to the normal function of many organs. While people with Alzheimer's disease are found to have local deposits of a type of amyloid protein—beta-amyloid peptide—in the brain, the actual cause of Alzheimer's remains unclear.

Researchers recently set out to evaluate if there is a relationship between different treatments for RA and the incidence of Alzheimer's dementia. They reviewed medical and pharmacy claims data of over eight million subjects in the U.S. from a commercial database (Verisk Health). A total of 42,193 people with RA were identified. Each RA subject with newly diagnosed Alzheimer's dementia was compared to 10 people with RA who did not have Alzheimer's dementia (called "controls"). As researchers made these comparisons, they ensured they were comparing people of the same age, gender, and with the same use of methotrexate, a medication commonly used for RA. Researchers examined the exposure of these individuals to several drugs used to treat RA including sulfasalazine, prednisone, three anti-TNFs (infliximab, etanercept, and adalimumab) and rituximab.

A total of 165 RA subjects with Alzheimer's dementia were compared to 1,383 RA controls without Alzheimer's dementia. Researchers found that those who received anti-TNF treatment had a 55 percent reduction in risk of developing Alzheimer's dementia. This effect was not seen with other drugs used for treatment of RA, including sulfasalazine, prednisone and rituximab
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The researchers concluded that anti-TNF agents used to treat people with RA may be useful in reducing the development of Alzheimer's dementia, although the mechanisms need further investigation.

"In this study, the incidence of Alzheimer's disease was found to be lower in patients with rheumatoid arthritis who had been treated with anti-TNF agents," says Dr. Richard Chou, MD, PhD; assistant professor at Dartmouth Medical School and lead investigator in the study. "Although the cause of Alzheimer's disease is not known, the results suggest that TNF may play a role in its development."

TNF-antagonists (also called biologics or anti-TNF therapy) are a class of drugs that have been used since 1998. Overall, they have been given to more than 600,000 people worldwide. These drugs are given to lessen inflammation by interfering with a biologic substance called TNF that cause or worsen inflammation.

Patients should talk to their rheumatologists to determine their best course of treatment.