By Linda Rath | Updated April 28, 2022
Being overweight can worsen rheumatoid arthritis (RA) symptoms, cause other health problems, and may make certain arthritis medications less effective. About two-thirds of people with RA are overweight or obese, the same proportion as the general population. But when you have RA, excess body fat can create additional problems.
Why obesity is important
Your body fat doesn’t just take up space. It is an active organ that releases hormones called adipokines. Some affect glucose metabolism; Others play a role in your immune system and regulate your appetite. If you’re at a healthy weight, your fat cells primarily produce beneficial adipokines. But excess fatty tissue releases high levels of cytokines, proteins that can cause inflammation throughout the body. These are the same proteins produced by joint tissue in RA. In addition to causing other health problems, cytokines worsen existing joint inflammation.
Disease progression
Obese people have more pain and disability than thinner people. However, they also have less inflammation and slower disease progression, as seen on imaging tests. Part of the problem may be a disconnect between physical exam findings (such as swollen joint counts) and what shows up on ultrasound or MRI. A physical examination may not be a particularly reliable way to determine disease activity and progression in people who are overweight.
Other health problems
Obesity not only makes arthritis worse; It also causes other health problems. The same fat-related cytokines that attack joints significantly increase the chances of developing type 2 diabetes and heart disease. Inflammatory cytokines make it difficult for insulin to enter cells. This causes glucose to build up in the blood and eventually leads to diabetes.
Inflammation also causes plaque to form more quickly in the arteries of people with RA. This slowly narrows blood vessels, blocks blood flow and is the leading cause of heart attacks and strokes. People with RA already have a 50% higher risk of cardiovascular mortality than the general population, says Dr. Jon Giles, associate professor of medicine, researcher and rheumatologist at Columbia University Medical Center. “You don’t want to have fat that increases your risk of heart disease,” he says.
Response to treatment
Some research suggests that certain arthritis medications, especially tumor necrosis factor (TNF) blockers, such as infliximab (remicade) and adalimumab (Humira) medications do not work as well when people with RA are obese. Other studies have found no difference in the effectiveness of medications based on weight. And one large study, using a decade’s worth of data from more than 23,000 veterans with RA, reported that methotrexate and TNF blockers were less effective in underweight and normal-weight people than in those who were overweight. Since there have been no direct comparisons of different medications in RA patients who are obese, there is no way to explain these varied results. Still, some doctors may increase the dose of a drug like infliximab in obese patients. According to French researcher Eric Toussirot, MD, fat cells can adhere to medications like infliximab, rendering them non-functional.
However, obese patients with RA have worse outcomes, a higher risk of other chronic diseases, and a poorer quality of life than patients with normal weight.
