Nov. 8, 2007 (Boston) -- People with rheumatoid arthritis (RA) who are overweight or obese may be less likely to go into remission when they are treated with a combination of conventional disease modifying anti-rheumatic drugs (DMARDs) and steroids than their thinner counterparts, a study shows.
But adding a biologic drug to the mix seems to help overweight and obese people with RA go into remission, reports researcher Marjatta Leirisalo-Repo, MD, PhD, a professor of rheumatology at Helsinki University Central Hospital in Helsinki, Finland.
The research was presented at the American College of Rheumatology Annual Scientific Meeting in Boston.
Affecting about 2.1 million Americans, RA is an autoimmune disease that occurs when the body attacks its own joints, causing pain, stiffness, swelling, and problems with mobility.
The new study included 100 people with recent-onset RA. Study participants received either combination therapy consisting of traditional DMARDs (methotrexate, sulfasalazine, hydroxychloroquine) along with steroids and either a dummy pill or the newer biologic drug Remicade.
The average age of participants was 46. They were grouped according to their body mass index (relation of weight to height). Being overweight is defined as a BMI of 25 to 29.9. A BMI that is 30 or higher is considered obese.
At the end of the 12-month study, 58% of participants with normal body weight on placebo plus combination therapy were in remission, compared with only 35% of those who were overweight and 25% of those who were obese.
By contrast, the effect of being overweight and going into remission was not seen in those study participants who were taking combination therapy and Remicade.
"Obesity (increasing body mass index) induces resistance to conventional anti-rheumatic drugs -- even in aggressive combination. [But Remicade] overcomes this resistance, probably due to its direct effect on inflammatory mediators," says Leirisalo-Repo.
RA Treatment for Overweight Patients
"People who are overweight have a lot of extra fat cells and those fat cells actually make proteins that are important for inflammation and important in the immune system," explains Eric Matteson, MD, a professor of medicine at the Mayo Clinic in Rochester, Minn.
For example, one such protein is tumor necrosis factor (TNF). This protein is a target of several drugs used to treat RA called TNF-blockers, including Remicade.
"If you are overweight, you have all this extra biochemical activity and the drugs we use have a hard time fighting against these inflammatory proteins," he says.
It's a double whammy if you are overweight and have RA, he says.
"People who are overweight have more trouble because their excess weight puts pressure on their joints, but also because their immune system is revved up more and fights against drugs," he tells WebMD.